JP2001197506A - Image coder and image decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To considerably reduce the number of bits required for coding an image signal or a shape signal without being almost accompanied with degradation in image quality. SOLUTION: The image coder of this invention is provided with a change pixel detector 2 that receives an input signal 1 and detects a pixel whose binary pixel value changes, a change pixel prediction device 4 that reads a reference image stored in a memory 3 to predict a change pixel of the input signal, a difference calculator 5 that subtracts an output of the change pixel prediction device 4 from an output of the change pixel detector 2, and a difference round- off device 7 that compares a permissible value (e) with prediction error D and outputs a value (x) with a minimum required bit number for coding with the value (x) denoted by D-e<=x<=D+e. The coder uses a difference between the detected change pixel and the predicted change pixel and a preset permissible value 6 to select a correction difference to minimize the code length of the error (difference) in the predicted error below the permissible value and outputs the selected correction difference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image encoding device and an image decoding device, and more particularly to an improvement in encoding efficiency in an image signal encoding process.

[0002]

2. Description of the Related Art Image coding has a long history, and ITU-T
Excellent standardization proposals such as H.261, ITU-T H.263, and ISO MPEG1 / 2 have been established. The image coding method is roughly classified into a coding method using orthogonal transform, and a prediction coding method using a prediction function to code an error from a predicted value. Although the coding method using the orthogonal transform is complicated in calculation, it is possible to perform coding with better image quality than predictive coding when obtaining a coded signal with a small number of bits. DCT (Discrete Cosine Transform) is used in a general encoding method using orthogonal transform such as JPEG and MPEG. It is known that DCT can be encoded with a small number of bits, but multiplication with high bit accuracy is required, which complicates the calculation.
The problem is that reversible encoding is not possible. Therefore, the DCT operation cannot be used in the field where reversibility is required.

[0003] On the other hand, predictive coding is characterized in that calculations are simple and lossless coding is also possible. As an image coding method having reversibility, MMR (Modified Modified Read) used in facsimile
Is famous. This is CCITTRec.T6 "Facsimilie Codi
ng Schemes and Coding Control Functions for Group
4 Facsimile Apparatus ", which uses a variable length horizontal difference value between the pixel value change point of the immediately preceding encoded scan line and the pixel value change point of the uncoded scan line. The MMMR (Modified MMR), which is a further improvement of this MMR, is adopted as an evaluation model of MPEG4 (ISO / IEC JTC / SC29 / WG11N1277, July
1996).

On the other hand, if the image signal is separated for each object and the shape of each separated object is handled as an arbitrary shape, and the image signal is handled,
Images can be manipulated or synthesized on a per-object basis, leading to efficient signal transmission. Also, in applications where the number of bits is restricted, by using such information, it becomes possible to selectively transmit and record important objects with priority. However, in the related art, encoding of an object having an arbitrary shape has not been considered. Then, standardization of encoding of an image signal having an arbitrary shape in ISO MPEG4 is progressing. MPEG4 now VM
An evaluation model called 3.0 (described in ISO / IEC JTC1 / SC29 / WG11 N1277) has been created, which is the only image encoding method known at present that can encode image signals having arbitrary shapes. Has become.

[0005] An image signal of an arbitrary shape generally includes shape information indicating the shape of an object and pixel value information (color information), which is a pixel value inside the object. As the shape information, each pixel value is significant (inside the shape)
Binary shape information indicating whether the image is insignificant (outside the shape) or transparency information indicating a ratio of each pixel (a ratio at which the object obscures the background) when combined with another image can be used. . When there are only two types of transparency, 0% and 100%, the shape information and the transparency information match, so that an image signal of an arbitrary shape can be expressed by two pieces of binary shape information and pixel value information.

FIG. 53 is a diagram for explaining such information. When synthesizing the image of the fish shown in FIG. 53 (a) with another image, the transparency information indicates what ratio is used by using each pixel of the image. FIG. 53 (a)
The values of the transmittance information in the horizontal scanning line direction indicated by dotted lines in FIG.
This is shown in FIG. The outside of the fish is completely transparent. Here, for convenience, transparency 0 is defined as completely transparent, so that the value of the transparency information outside the fish is 0, whereas the value inside the fish is non-zero.

[0007] FIG. 53 (c) shows that the transparency information is binarized assuming that the transparency is two types of 0 and non-zero.
In FIG. 53 (c), a pixel having a non-zero transparency requires encoding of pixel value information, but a pixel having a transparency of 0 does not require pixel value information. The quantified transparency information is very important. On the other hand, FIG.
The component of the transparency information that cannot be represented by binary information is multi-valued information called gray scale, and the shape information represented as multi-valued information has the same waveform coding Can be performed.

In image coding, intra-screen (frame) coding based on spatial correlation and inter-screen (frame) coding based on temporal correlation are selectively used or used together. . When performing inter-picture coding, a motion in an adjacent picture is detected, and the motion is compensated for the motion. Generally, a motion vector is used for motion compensation. In VM3.0 mentioned above,
Intra-screen coding and inter-screen coding are adaptively switched in block units, and motion compensation similar to MPEG1 / 2 is performed to improve coding efficiency.

As described above, when an image composed of shape information and pixel value information is encoded, the shape information used for synthesizing the image is calculated using the motion vector of the pixel value information. Compensation coding can improve the coding efficiency compared to coding shape information directly.
/ IEC Reported in JTC1 / SC29 / WG11 N1260 March 1996. When performing motion detection and motion compensation, the shape information is separated into a binary shape information component and a multi-value information component, and the same waveform encoding is performed on the multi-value information component together with the pixel value information. Was considered efficient and was treated as such.

[0010]

As described above, the following problems exist in the conventional image coding and the accompanying image decoding. As described above, MMR coding is a typical example of lossless (lossless) coding. However, since it is lossless, the compression rate is greatly improved by allowing visually insignificant image quality deterioration. It is impossible. Also, MMR is an intra-screen encoding technique, and does not consider the improvement of the compression ratio using correlation between screens. The MMR and the improved method MMMR use only the difference between the change point of the current scan line and the change point of the immediately preceding scan line, and the connection (correlation) as a straight line in the vertical direction is redundant. Not sufficiently removed. Therefore, when the change in pixel value is along the scanning line, the coding efficiency is high, but when the change is not along the scanning line, the coding efficiency is low. Also, MMR and MMMR have a horizontal encoding mode that does not use any vertical correlation in order to encode pixels that cannot be encoded as a difference value of a change point of the immediately preceding scan line. This horizontal coding mode also has room for further improvement in efficiency by utilizing the correlation in the vertical direction.

Furthermore, in the conventional MMR or MMMR, it is not possible to reproduce an image hierarchically by decoding a part of a bit stream, and encoding is performed by another method capable of hierarchical image reproduction. There is a drawback that the efficiency is low and the number of coded bits increases, and there is no coding method that enables effective hierarchical image reproduction. Further, when an image composed of shape information and image information is encoded by motion compensation, conventionally, motion compensation was performed on the shape information using the same motion vector as the image information. In such a case, the motion vector of the image information and the motion vector of the shape information generally do not coincide with each other so that the figure drawn on the sphere moves while the shape does not change. Therefore, it is a problem of the conventional encoding method that good encoding cannot be performed in such a case.

As described above, in VM3.0, the coding efficiency is improved by adaptively switching between intra-frame coding and inter-frame coding in block units. Judgment for image conversion is determined based on pixel value information, as in the case of adaptive switching in MPEG1 / 2.
It has been difficult to properly and efficiently encode shape information having a property greatly different from that of pixel value information. The present invention has been made in view of such a point, and an image encoding apparatus capable of efficiently encoding an image signal, and appropriately decoding the efficiently encoded signal. It is an object of the present invention to provide an image decoding device capable of performing such operations.

[0013]

An image encoding apparatus according to the present invention (claim 1) uses a binary image signal as an input signal and encodes a pixel whose pixel value changes in the input signal. An apparatus, wherein a changed pixel detecting means for detecting a pixel whose pixel value changes, and outputting the detected changed pixel as a detected changed pixel, and a pixel whose pixel value of an encoded and decoded pixel changes. A prediction unit that predicts a change pixel of the input signal and outputs the predicted pixel as a prediction pixel; a difference between the detected change pixel and the prediction change pixel; And a value within a range determined based on the preset allowable value and the difference value D, and a value that minimizes the code length when encoded. Select some D 'and correct this A rounding means for outputting a binary value, a decoding means for decoding a binary image signal from the corrected difference value D 'and the predicted changed pixel, and an encoding means for coding the corrected difference value D' It is provided with.

An image encoding apparatus according to the present invention (claim 2) is an image encoding apparatus which receives a binary image signal as an input signal and encodes a pixel whose pixel value of the input signal changes. A pixel change means for detecting a pixel whose pixel value changes, and outputting the detected change pixel as a detected change pixel, based on the pixel whose pixel value changes, of the encoded and decoded pixels in the frame. A first predictor for predicting a changed pixel of the input signal and outputting the predicted pixel as a first predicted pixel; calculating a difference between the detected changed pixel and the first predicted pixel; A first difference value calculating unit that outputs the calculated difference as a first difference value D, and, based on a pixel whose pixel value changes, of the coded and decoded pixels in the reference frame, with motion compensation, Input above A second prediction means for predicting a changed pixel of the signal and outputting the predicted pixel as a second predicted pixel, calculating a difference between the detected changed pixel and the second predicted pixel, and calculating the calculated difference Is output as a second difference value D ″, and the first difference value D
And the second difference value D ″, calculate the code length when each is encoded, compare the calculation results and select the one with the shorter code length. A mode selecting means for outputting either the "first" or "second" as the encoding mode, the selected first differential value D or the second differential value D ", and the mode selecting means outputting Encoding means for encoding the encoding mode.

An image coding apparatus according to the present invention (claim 3) is an image coding apparatus which receives a two-dimensional binary image signal as an input signal and codes pixels whose pixel values of the input signal change. A changed pixel detecting means for detecting a pixel whose pixel value changes, and outputting the detected changed pixel as a detected changed pixel; and scanning the image signal in the horizontal direction, thereby encoding and decoding the pixels. Based on the pixel of which the pixel value changes, predict the change pixel of the input signal,
A first outputting the predicted pixel as a first predicted pixel
And a difference between the detected changed pixel and the first predicted pixel, and calculates the calculated difference as a first difference value D
A first difference value calculating unit that outputs a pixel value of the input signal based on a pixel of which the pixel value of the coded and decoded pixel changes by scanning the image signal in the vertical direction. And predicting the predicted pixel as a second
A second prediction means that outputs the predicted pixel as a predicted pixel, a second difference that calculates a difference between the detected change pixel and the second predicted pixel, and outputs the calculated difference as a second difference value D ″ Value calculating means, calculating a code length when each of the first difference value D and the second difference value D ″ is coded, and comparing the calculation results to shorten the code length. And a mode selecting means for outputting either “first” or “second” as the encoding mode in response to the selection, and the selected first difference value D or second difference Encoding means for encoding the value D "and the encoding mode output by the mode selecting means.

An image encoding apparatus according to the present invention (claim 4) is an image encoding apparatus which receives a multivalued image signal as an input signal and encodes a pixel whose pixel value of the input signal changes. Detecting a pixel whose pixel value changes to a predetermined value or more,
A changed pixel detecting unit that outputs the detected pixel as a detected changed pixel, and predicts a changed pixel of the input signal based on a pixel having a changed pixel value of the coded and decoded pixel. , A difference value calculating means for calculating a difference between the detected change pixel and the predicted pixel, and outputting the calculated difference as a difference value D. An encoding unit for encoding the pixel value of the changed pixel, and a decoding unit for decoding a multi-valued image signal from the difference value D and the pixel value of the changed pixel.

The image coding apparatus according to the present invention (claim 5) uses an image signal consisting of a transmittance signal indicating a ratio at the time of combining images and a pixel value signal as an input signal, and refers to a reference image. An image encoding apparatus that encodes the input signal by comparing a pixel value signal of the input signal with a pixel value signal of the reference image to detect a motion vector of the pixel value signal. Motion vector detecting means, first motion compensating means for performing motion compensation on the pixel value signal of the reference image using the motion vector of the pixel value signal, and outputting a compensated pixel value signal, and pixel value of the input signal First difference value calculating means for calculating a difference between the signal and the compensated pixel value signal and outputting a first difference value; and a first encoding means for encoding the first difference value Means, a transparency signal of the input signal, and the reference image A second motion vector detecting unit that compares the transparency signal with the transparency signal to detect a motion vector of the transparency signal, and performs motion compensation on the transparency signal of the reference image using the motion vector of the transparency signal; A second motion compensating means for outputting a compensation transmittance signal; a second value for calculating a difference value between the two from the transmittance signal of the input signal and the compensation transmittance signal; and outputting a second difference value. Means for calculating the difference value of
A second encoding unit that encodes the second difference value; and a third encoding unit that encodes a motion vector of the pixel value signal and a motion vector of the transparency signal. is there.

According to a sixth aspect of the present invention, in the image encoding apparatus according to the fifth aspect, the second motion vector detecting means is detected by the first motion vector detecting means. The motion vector of the transmittance signal is detected by comparing the transmittance signal of the input signal and the transmittance signal of the reference image near the motion vector.

According to a seventh aspect of the present invention, in the image encoding apparatus according to the fifth aspect, the first motion vector detecting means is detected by the second motion vector detecting means. In the vicinity of the motion vector, the pixel value signal of the input signal is compared with the pixel value signal of the reference image to detect a motion vector of the pixel value signal.

[0020] In the image encoding apparatus according to the present invention (claim 8), in the image encoding apparatus according to claim 5, the third encoding means includes: a motion vector of the pixel value signal;
A difference value between the motion vector of the transmittance signal and the motion vector of the pixel value signal is encoded.

According to a ninth aspect of the present invention, in the image encoding apparatus of the fifth aspect, the third encoding means includes a motion vector of the transparency signal,
A difference value between the motion vector of the transmittance signal and the motion vector of the pixel value signal is encoded.

An image coding apparatus according to the present invention (claim 10) is a block-shaped image signal comprising a shape signal indicating whether the shape of an object and a pixel value of each pixel is significant, and a pixel value signal. An image encoding apparatus that encodes the input signal with reference to a reference image, using the image signal having the shape as an input signal, and comparing a pixel value signal of the input signal with a pixel value signal of the reference image. A first motion vector detecting means for detecting a motion vector of the pixel value signal; and a motion compensation of the pixel value signal of the reference image using the motion vector of the pixel value signal, and outputting a compensated pixel value signal. First motion compensating means, a first difference value calculating means for calculating a difference between the two from the pixel value signal of the input signal and the compensated pixel value signal, and outputting a first difference value; A first encoding of the first difference value Encoding means, a shape signal of the input signal, and a shape signal of the reference image, a second motion vector detection means for detecting a motion vector of the shape signal, and a shape signal of the reference image, From the second motion compensating means for performing motion compensation using the motion vector of the shape signal and outputting a compensation shape signal, the shape signal of the input signal, and the compensation shape signal, a difference value between the two is calculated, Second difference value calculating means for outputting a second difference value, second coding means for coding the second difference value, a motion vector of the pixel value signal, and a motion vector of the shape signal And a third encoding means for encoding

[0023] In the image encoding apparatus according to the present invention (claim 11), in the image encoding apparatus according to claim 10, the second motion vector detecting means is detected by the first motion vector detecting means. In the vicinity of the calculated motion vector,
The shape signal of the input signal is compared with the shape signal of the reference image to detect a motion vector of the shape signal.

According to a twelfth aspect of the present invention, in the image encoding apparatus according to the tenth aspect, the first motion vector detecting means is detected by the second motion vector detecting means. In the vicinity of the calculated motion vector,
The pixel value signal of the input signal is compared with the pixel value signal of the reference image to detect a motion vector of the pixel value signal.

According to a thirteenth aspect of the present invention, in the image encoding apparatus according to the tenth aspect, the third encoding means includes a motion vector of the pixel value signal and the shape vector. It encodes a difference value between the motion vector of the signal and the motion vector of the pixel value signal.

According to a fourteenth aspect of the present invention, in the image encoding apparatus according to the tenth aspect, the third encoding means includes a motion vector of the shape signal and the shape signal. And a difference value between the motion vector of the pixel value signal and the motion vector of the pixel value signal.

[0027] In the image coding apparatus according to the present invention (claim 15), in the image coding apparatus according to claim 10, the shape signal of the input signal indicates that all pixel values are significant. The compensation shape signal obtained by motion-compensating the shape signal of the reference image using the motion vector of the pixel value signal detected by the first motion vector detection means indicates that all pixel values are significant. In some cases, or the shape signal of the input signal indicates that the pixel values are not all significant, and the motion vector of the pixel value signal detected by the first motion vector detection means is used to generate the reference image. If the compensated shape signal obtained by motion-compensating the shape signal indicates that all pixel values are not significant, the second vector detecting means does not detect a motion vector of the shape signal, and With motion vector of the detected pixel value signal in the vector detecting means, in which it is assumed that the motion vector of the shape signal.

[0028] An image coding apparatus according to the present invention (claim 16) is the image coding apparatus according to claim 10, wherein the motion vector of the pixel value signal detected by the first motion vector detecting means is used. Comparing the compensated shape signal obtained by motion-compensating the shape signal of the reference image with the shape signal of the input signal, and when the difference of the comparison result is smaller than a preset allowable value, the first vector detecting means No motion vector of the value signal is detected, and the motion vector of the shape signal detected by the second vector detection means is used as the motion vector of the pixel value signal.

[0029] In an image encoding apparatus according to the present invention (claim 17), in the image encoding apparatus according to claim 10, the third encoding means outputs the input signal in the immediately preceding input signal. When the motion vector of the shape signal of the signal is coded, the difference value between the motion vector of the shape signal coded immediately before and the motion vector of the shape signal detected from the input signal is coded. It is.

[0030] In the image encoding apparatus according to the present invention (claim 18), in the image encoding apparatus according to claim 10, the third encoding means outputs the input signal in the immediately preceding input signal. When the motion vector of the pixel value signal of the signal has been encoded, encodes a difference value between the motion vector of the immediately preceding pixel value signal and the motion vector of the pixel value signal detected from the input signal. It is what it was.

[0031] In the image encoding apparatus according to the present invention (claim 19), in the image encoding apparatus according to any one of claims 10 to 18, the input signal is a composite signal for synthesizing a plurality of images. Transparency information including information indicating a ratio;
When the image information is composed of image information, the transparency information is the shape signal, and the image information is the pixel value signal.

[0032] In the image encoding apparatus according to the present invention (claim 20), in the image encoding apparatus according to any one of claims 10 to 18, the input signal may be a synthesizing signal for synthesizing a plurality of images. Transparency information including information indicating a ratio;
In the case of being composed of image information, the transparency information is separated into a binary signal representing only a shape and a residual shape signal which is another signal, and the separated binary signal is converted into the shape signal. A signal, wherein the separated residual shape signal and the image information are used as the pixel value signal.

The image coding apparatus according to the present invention (claim 21) is characterized in that shape information indicating whether the pixel value of each pixel of the object is significant, and transparency information indicating the combination ratio of each pixel of the object. And an image signal comprising an image signal composed of at least one of the pixel value information and the pixel value information as an input image signal, wherein pixels that spatially and temporally match the input image signal as one group. Blocking means for integrating and outputting the information as blocked information, and a predetermined encoding mode for each of the shape information, the transparency information, and the pixel value information blocked by the blocking means. A first encoding unit that selects an encoding mode from among the encoding modes, and encodes each of the encoding modes in the selected encoding mode. Second encoding means for collectively encoding the mode identification information indicating the selected mode for each of the reports, wherein the output of the first encoding means and the output of the second encoding means are provided. Are encoded outputs.

The image coding apparatus according to the present invention (claim 22) is characterized in that shape information indicating whether the pixel value of each pixel of the object is significant, and transparency information indicating the composition ratio of each pixel of the object. And an image signal comprising an image signal composed of at least one of the pixel value information and the pixel value information as an input image signal, wherein pixels that spatially and temporally match the input image signal as one group. Blocking means for integrating and outputting as blocked information, and the shape information and the transparency information blocked by the blocking means are coded from a predetermined coding mode. A first encoding unit that selects a mode and encodes each of the selected encoding modes, and one of the encoding modes selected by the first encoding unit. In the encoding mode, a second encoding unit that encodes the pixel value information blocked by the blocking unit, and each of the shape information, the transmittance information, and the pixel value information, A third encoding unit that encodes the mode identification information indicating the selected mode collectively, the first encoding unit output, the second encoding unit output, and the third code The output of the encoding means is an encoded output.

The image coding apparatus according to the present invention (claim 23) is characterized in that shape information indicating whether the pixel value of each pixel of the object is significant, and transparency information indicating the combination ratio of each pixel of the object. And an image signal comprising an image signal composed of at least one of the pixel value information and the pixel value information as an input image signal, wherein pixels that spatially and temporally match the input image signal as one group. Blocking means for integrating and outputting the information as blocked information, and for the pixel value information blocked by the blocking means, selecting an encoding mode from a predetermined encoding mode, Encoding in the encoded encoding mode
And second encoding for encoding the shape information information and the transparency information which are blocked by the blocking means in the encoding mode selected by the first encoding means. Means, the shape information,
The transparency information, and, for each of the pixel value information, mode identification information indicating the selected mode,
And third encoding means for encoding together, wherein the output of the first encoding means, the output of the second encoding means, and the output of the third encoding means are encoded outputs. is there.

According to a twenty-fourth aspect of the present invention, in the image encoding apparatus according to any one of the twenty-first to twenty-third aspects, the predetermined encoding mode includes intra-screen encoding and screen encoding. It is assumed to be inter-coding.

According to a twenty-fifth aspect of the present invention, in the image coding apparatus according to the twenty-second or twenty-third aspect, the second coding means is the first coding means. When the selected encoding mode is intra-screen encoding, intra-frame encoding is selected.

According to a twenty-sixth aspect of the present invention, in the image encoding apparatus according to any one of the twenty-first to twenty-third aspects, the predetermined encoding mode is such that: It is assumed to be the number.

The image encoding apparatus according to the present invention (claim 27) is the image encoding apparatus according to claim 22 or 23, wherein the second encoding means is the first encoding means. The number of motion vectors in the selected encoding mode is selected as the encoding mode.

[0040] According to an image coding apparatus of the present invention (claim 28), in the image coding apparatus of any one of claims 21 to 23, the predetermined coding mode includes a quantization step change, and It is assumed that there is no change in the quantization step.

The image encoding apparatus according to the present invention (claim 29) is the image encoding apparatus according to claim 22 or 23, wherein the second encoding means is the first encoding means. When the selected encoding mode has no quantization step change, no quantization step change is selected.

An image encoding apparatus according to the present invention (claim 30) is an image encoding apparatus which inputs and encodes a two-dimensional image signal composed of a plurality of pixels. A first changed pixel detecting unit that detects a pixel whose pixel value changes by scanning in a predetermined direction, and outputs the detected first changed pixel; A second changing pixel detecting unit that detects a pixel whose pixel value changes by scanning in a predetermined direction and outputs the detected second changing pixel, and encodes and decodes a pixel, A third changing pixel detecting means for detecting a pixel whose pixel value changes by scanning in a predetermined direction and outputting the detected third changing pixel; the second changing pixel and the third changing pixel The first change based on the pixel A modified pixel predictor for predicting a pixel and outputting the predicted predicted changed pixel; calculating a difference between the first changed pixel and the predicted changed pixel; outputting the calculated changed pixel difference value Prediction error calculating means to
Prediction error encoding means for encoding the changed pixel difference value to generate an encoded signal.

The image coding apparatus according to the present invention (claim 31) is the image coding apparatus according to claim 30, wherein the second changed pixel detecting means and the third changed pixel detecting means are: The pixel values of the second changed pixel and the third changed pixel are the same as the pixel values of the first changed pixel.

The image coding apparatus according to the present invention (claim 32) is the image coding apparatus according to claim 30, wherein the second changed pixel detecting means and the third changed pixel detecting means are: The predetermined scanning direction is the same as the predetermined scanning direction of the first changed pixel detection unit.

The image coding apparatus according to the present invention (claim 33) is the image coding apparatus according to claim 30, wherein the difference between the second pixel and the changed pixel predicted by using the second changed pixel. It is assumed that three changed pixels are coded.

An image coding apparatus according to the present invention (claim 34) is the image coding apparatus according to claim 30, wherein the second changed pixel, the third changed pixel, and the first changed pixel are different. It is assumed that it is on the scanning line.

The image coding apparatus according to the present invention (claim 35) is the image coding apparatus according to claim 30, wherein the changed pixel predicting means is configured such that the second changed pixel is x in the m-th scanning line. In the pixel position, the third change pixel corresponds to the n-th scanning line.
When it is at the y-th pixel, the k-th pixel
It is assumed that the pixel is predicted to be the y- (xy) * (nk) / (mn) th pixel of the scanning line.

An image coding apparatus according to the present invention (claim 36) is an image coding apparatus for inputting and coding a two-dimensional image signal composed of a plurality of pixels. Detecting a pixel whose pixel value changes by scanning in a predetermined direction, changing pixel detecting means for outputting the detected detected changed pixel, and predicting a changed pixel from encoded and decoded pixels; A change pixel prediction means for outputting a predicted change pixel predicted, a prediction error calculation means for calculating a difference between the detected change pixel and the predicted change pixel, and outputting the calculated change pixel difference value; A prediction error encoding unit that encodes the changed pixel difference value when the value of the pixel difference value is smaller than a predetermined value and outputs a difference value encoded signal; In some cases, just before From the coded changed pixel, the number of pixels that are located between the detected changed pixel and the pixel positions that can be coded by the prediction error coding unit are calculated, and the calculated number of pixels is coded. And a pixel number encoding unit that outputs a pixel number encoding signal, wherein the prediction error encoding unit and the pixel number encoding unit include the difference value encoding signal and the pixel number encoding signal. Perform encoding that can be uniquely identified.

The image coding apparatus according to the present invention (claim 37) is the image coding apparatus according to claim 36, wherein said prediction error coding means and said pixel number coding means are characterized by: The predetermined value to be compared with the value is set using the number of pixels of the scanning line.

An image encoding apparatus according to the present invention (claim 38) is an image encoding apparatus which receives a two-dimensional shape signal representing an area where a pixel representing an object is present and encodes the shape signal. Means for extracting a significant area that is a rectangular area including pixels representing the object from the input shape signal, and outputting a significant area range that is a range of the extracted significant area; Blocking means for dividing a signal into blocks consisting of a plurality of pixels, and for each block output by the blocking means, determine whether or not to include the significant region, and if it is determined to include the significant region, And a shape encoding unit that encodes at least the significant region of the block and outputs a shape-encoded signal, wherein the significant region range and the shape-encoded signal are used as encoded signals. Than it is.

The image coding apparatus according to the present invention (claim 39) is the image coding apparatus according to claim 38, wherein the shape coding means comprises: The minimum rectangular area including the significant area is extracted, and only the inside of the extracted rectangular area is encoded.

An image encoding apparatus according to the present invention (claim 40) is an image encoding apparatus which encodes the two-dimensional image signal by inputting a two-dimensional image signal composed of a plurality of pixels, Is separated into at least two image signals, an image signal separating unit that outputs the separated image signals as two or more partial image signals, and at least one of the partial image signals is selected as a target partial image signal. ,
A first image signal encoding unit that encodes the selected target partial image signal and outputs a first encoded signal; and the partial image signal based on the image signal obtained by decoding the first encoded signal. Prediction probability calculating means for predicting a non-target partial image signal in the image signal excluding the target partial image signal, calculating a probability that the prediction is successful, and outputting the calculated prediction probability; and Means for determining the priority of decoding according to the prediction probability calculated by the means, and encoding the non-target partial image signal using an encoding method corresponding to the determined priority path. Encoding means.

[0053] In the image coding apparatus according to the present invention (claim 41), in the image coding apparatus according to claim 40, the second image signal coding means preferentially gives a pixel having a small prediction probability. Thus, the priority of the decoding is determined so as to be decoded.

[0054] In the image encoding apparatus according to the present invention (claim 42), in the image encoding apparatus according to claim 40, the prediction probability calculating means is configured to execute the above-described target coding when neighboring pixel values are the same. The probability of hitting is large, and when the neighboring pixel values are different, the probability of hitting is reduced.

An image decoding apparatus according to the present invention (Claim 43) is an image decoding apparatus which receives an encoded signal and decodes the encoded signal. A decoding unit that obtains a difference value, and outputs the obtained difference value as a decoding difference value, using the obtained encoding mode as a mode signal, and a pixel of the coded and decoded pixel in the frame First prediction means for predicting a changed pixel of the input signal based on a pixel whose value changes, and outputting the predicted pixel as a first predicted pixel; and a coded and decoded pixel in a reference frame. A second prediction unit that predicts a changed pixel of the input signal based on a pixel whose pixel value changes, with motion compensation, and outputs the predicted pixel as a second predicted pixel; When indicating the frame prediction,
Adding means for adding the decoding difference value to the first prediction pixel, and when the mode signal indicates reference frame prediction, adding the decoding difference value to the second prediction pixel. Is used as the change pixel.

An image decoding apparatus according to the present invention (Claim 44) is an image decoding apparatus which receives an encoded signal and decodes the encoded signal. Decoding means for obtaining a difference value, outputting the obtained difference value as a decoding difference value using the obtained coding mode as a mode signal, and scanning the image signal in the horizontal direction to perform coding. First prediction means for predicting a changed pixel of the input signal based on a pixel having a changed pixel value of a decoded pixel, and outputting the predicted pixel as a first predicted pixel; Is scanned in the vertical direction to predict a changed pixel of the input signal based on a pixel whose pixel value of the coded and decoded pixel changes, and outputs the predicted pixel as a second predicted pixel Do (2) adding the decoding difference value to the first prediction pixel when the mode signal indicates the prediction of the horizontal scanning, and adding the decoding difference value when the mode signal indicates the prediction of the vertical scanning. Adding means for adding the decoded difference value to the second predicted pixel, wherein the output of the adding means is a changed pixel.

An image decoding apparatus according to the present invention (claim 45) is an image decoding apparatus for receiving a coded signal and decoding the coded signal by decoding the coded signal to obtain a difference value,
A decoding unit that obtains a pixel value of the changed pixel, outputs the obtained difference value as a decoded difference value, and outputs the obtained pixel value of the changed pixel as a decoded pixel value, and a pixel value of the decoded pixel. Based on the changing pixel, predicting a changed pixel of the input coded signal, predicting means for outputting the predicted pixel as a predicted pixel, adding the decoded difference value and the predicted pixel, and The image processing apparatus further includes an adding unit that outputs a result as a corrected difference value, and an image decoding unit that obtains a multilevel image signal by a decoding process from the corrected difference value and the decoded pixel value.

An image decoding apparatus according to the present invention (claim 46) is an image decoding apparatus for inputting and decoding an encoded signal, and for decoding a difference value of a pixel value signal from the encoded signal. First decoding means for converting the encoded signal into a decoded pixel value difference value, outputting a decoded signal difference value from the coded signal, and outputting the decoded signal as a decoded transmittance difference value; Third decoding means for decoding the motion vector of the pixel value signal and the motion vector of the transparency signal from the encoded signal, and outputting a decoded pixel value motion vector and a decoded transparency motion vector; Of the pixel value signal is subjected to motion compensation using the decoded pixel value motion vector,
First motion compensating means for outputting the result of the motion compensation as a compensated pixel value signal, adding the decoded pixel value difference value and the compensated pixel value signal, and outputting the sum as a decoded pixel value signal And a first adding means for outputting a pixel value signal of the reference image, and a transparency signal of the reference image, which will be described later, being motion-compensated using the decoded transparency motion vector. A second motion compensating means for outputting as a degree signal, adding the decoded transmittance difference value and the compensated transmittance signal, outputting the result of the addition as a decoded transmittance signal, And a second adding means for outputting as a signal.

The image decoding apparatus according to the present invention (claim 47) is the image decoding apparatus according to claim 46, wherein the third decoding means comprises: a motion vector of a pixel value signal;
Decode the difference value of the motion vector to obtain a decoded pixel value motion vector and a decoded motion vector difference value, and add the decoded pixel value motion vector and the decoded motion vector difference value to obtain the decoded transparency motion vector. It is something that was taken.

[0060]

Embodiments of the present invention will be described below. Embodiment 1 FIG. The image coding apparatus according to the first embodiment of the present invention performs efficient coding by selecting a difference value having a short coding length within a predetermined range when performing predictive coding. is there. FIG. 1 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes an input signal, which is input to the image encoding device as a binary image signal. Reference numeral 2 denotes a change pixel detector which detects a pixel whose pixel value changes with respect to the input signal 1 and outputs the detected change pixel. Reference numeral 3 denotes a memory that temporarily stores encoded and decoded image signals used as reference images. Reference numeral 4 denotes a change pixel predictor which predicts a change pixel output from the change pixel detector 2 based on a pixel whose pixel value of the reference image changes, and outputs a predicted change pixel. As a prediction method that can be used by the changing pixel predictor 4, for example, based on a strong vertical correlation of a two-dimensional image signal, a representative that predicts that a changing pixel exists at the same horizontal position as a changing pixel of a scanning line at an upper position is used. For example, a predictive method can be used. Reference numeral 5 denotes a difference value calculator which calculates a difference value between the changed pixel detected by the changed pixel detector 2 and the predictor 4.
Calculate D. Reference numeral 6 denotes a value e which is preset as an allowable value of the rounding error and is provided to the difference value rounder. Reference numeral 7 denotes a difference value rounder which corrects the difference value D within a range defined by the allowable value e and outputs a corrected difference value D '.
Reference numeral 8 denotes an encoder, which encodes a difference value. Reference numeral 9 denotes an encoded signal output from the encoder 8. Reference numeral 11 denotes a difference value adder, which outputs a corrected difference value D 'output from the difference rounder 7;
The predicted change pixel output from the change pixel predictor 4 is added. Reference numeral 10 denotes a changing pixel decoder, and a difference value adder 11
The binary pixel value is decoded by using the addition result output from.

The operation of the image coding apparatus according to the first embodiment configured as described above will be described. When an input signal 1 which is a binary image signal is input to the apparatus, the change pixel detector 2 receives the input signal 1 and detects a pixel whose binary pixel value changes. On the other hand, the changed pixel predictor 4 reads the reference image stored in the memory 3 and predicts a changed pixel in the input signal. The changed pixel detector 2 outputs the detected result to the difference value calculator 5 as a detected changed pixel, and the changed pixel predictor 4 outputs the predicted result to the difference value calculator 5 as a predicted changed pixel. Then, the difference value calculator 5 subtracts the predicted change pixel from the detected change pixel to obtain a difference value D corresponding to the prediction error of the changed pixel. The difference value calculator 5 outputs the difference value D to the difference value rounder 7. The difference value rounder 7 includes a predetermined allowable value e,
The difference value D 2 corresponding to the prediction error output from the difference value calculator 5 is compared. If the difference value D does not exceed the allowable value e, the value x satisfies De ≦ x ≦ D + e. , A value x that minimizes the number of bits when the value x is encoded is obtained and output as a modified difference value D ′. On the other hand, when the difference value D corresponding to the prediction error exceeds the allowable value e, a corrected difference value D ′ is obtained based on the allowable value e and is output to the encoder 8. Then, the modified difference value D ′ is encoded by the encoder 8 to become an encoded signal 9. The corrected difference value D ′ output from the difference value rounder 7 is also output to the difference value adder 11. In the difference value adder 11, the corrected difference value D ′ is added to the predicted change pixel output from the change pixel predictor 4 to calculate a change pixel of the pixel value. Is output. The changed pixel decoder 10 decodes the pixel value of each pixel from the decoded pixel indicated by the output of the changed pixel predictor 4 to the pixel of the changed pixel input from the difference value adder 11. It is stored in the memory 3. Thus, the content stored in the memory 3 is used as a reference image.

The above operation will be specifically described with reference to FIG. FIG. 2 is a model of a binary image signal, in which each pixel value is represented by a rectangular shape of white and black (fine hatched lines).
Here, for the sake of simplicity, the processing procedure will be described assuming that one pixel is sequentially processed. FIG. 2A shows an input signal, which scans from the upper left to the right, and the process proceeds to the lower right. A pixel whose pixel value changes (white → black or black → white) on one line (scanning line) is a change pixel. Pc in FIG. 2B is the last pixel that has been encoded,
u is assumed to be a changing pixel in the scanning line at the upper position, and a coarse hatched portion represents a pixel that has not been encoded yet. The changed pixel detector 2 checks a changed pixel whose pixel value changes for a part of the input signal shown in FIG. 2A which has not been coded as shown in FIG.
P1 is detected, and this is used as a detected change pixel.
Output to

On the other hand, the change pixel predictor 4 predicts a change pixel by the above-described method, and changes the change pixel Pu of the upper scanning line.
Pixel P0 is predicted at the same horizontal position as above, and is output to difference value calculator 5 as a predicted change pixel. The difference value calculator 5 outputs D = 1 to the difference rounder 7 as a difference value between the detected change pixel P1 and the predicted change pixel P0. Here, the settings of the image encoding device according to the first embodiment include:
It is assumed that encoding is performed to assign a code with a shorter code length as the difference value from P0 is smaller. And the rounding error tolerance e
It is assumed that 1 has been given. Since the difference between P1 and P0 obtained by the difference value calculator is equal to or smaller than e, the difference value rounder 7 outputs
D "= 0. As a result, the changed pixel is rounded,
Since the pixel value is subjected to the decoding process, the encoded and decoded pixel values are as shown in FIG.

On the other hand, when the input signal is as shown in FIG. 2D, as shown in FIG. 2E, the difference indicated by the difference between the predicted change pixel P0 and the detected change pixel P1 is obtained. Since the value D is 2, the difference value D exceeds the allowable value e in this case. Therefore, the difference value rounder 7 calculates the prediction error (difference value)
Is corrected based on the allowable value e so as not to exceed the allowable range, and the difference value −1 corresponding to the changed pixel P2 is output. As a result, the encoded and decoded pixel values are as shown in FIG. As described above, the image encoding device according to the first embodiment includes the difference value rounder 7 and uses the difference value between the detected changed pixel and the predicted changed pixel, and the preset allowable value 6. For a prediction error equal to or less than the allowable value, a corrected difference value that minimizes the code length of the error (difference value) is selected and output. The number of necessary bits can be greatly reduced. The coded signal 9 obtained by the image coding device according to the first embodiment can be decoded by a normal image decoding device.

Embodiment 2 The image coding apparatus according to Embodiment 2 of the present invention performs processing by adaptively switching between coding based on prediction using the frame and coding based on prediction with motion compensation using a reference frame. is there. FIG. 3 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 2 of the present invention. In the figure, 2
Reference numeral 0 denotes a motion compensator, which performs motion compensation on the image signal of the encoded and decoded reference frame to generate a reference pixel value. Reference numeral 21 denotes a mode selector, which compares a difference value obtained when the prediction based on the image signal of the frame is performed with a difference value obtained when the prediction is performed based on the image signal of the reference frame, and performs encoding. Is selected as the encoding mode. Reference numeral 22 denotes a switch which selects and outputs a difference value corresponding to the encoding mode selected by the mode selector 21. Reference numerals 1 to 9 are the same as in FIG. 1 and the description is the same as in the first embodiment;

The operation of the thus configured image encoding apparatus of the second embodiment will be described. When an input signal 1 which is a binary image signal is input to the apparatus, the input signal 1 is input to a changing pixel detector 2 and a memory 3
Is stored in the memory 3 and is used as an encoded and decoded reference image in the frame. The change pixel detector 2 receives the input signal 1
Is input, a pixel whose binary pixel value changes is detected. The changed pixel detector 2 outputs the detected result to the difference value calculators 5a and 5b as a detected changed pixel. On the other hand, the changed pixel predictor 4a reads out the encoded and decoded reference image of the frame stored in the memory 3, predicts the changed pixel based on the input signal, and uses the result as a predicted changed pixel to calculate the difference. Output to the value calculator 5a. Then, the difference value calculator 5a subtracts the predicted change pixel from the detected change pixel to obtain a difference value D. Output D of difference value calculator 5a
Is equivalent to the prediction error of the changed pixel predicted based on the encoded and decoded pixels in the frame, and the difference value calculator 5a compares the difference value D with the mode selector 21 and the switch 22. Output to

The motion compensator 20 performs motion compensation on the coded and decoded image of the reference frame stored in the memory 3, and the change pixel predictor 4 b uses the input pixel based on the motion-compensated pixel. A changed pixel of the signal is predicted, and the result is output to the difference value calculator 5b as a predicted changed pixel.
The difference value calculator 5b subtracts the predicted change pixel from the detected change pixel to obtain a difference value D ". Output of the difference value calculator 5b
D "corresponds to the prediction error of the changed pixel predicted with the motion compensation based on the encoded and decoded pixels in the reference frame, and the difference value calculator 5b calculates the difference value
D "is output to the mode selector 21 and the switch 22.
The mode selector 21 compares the code length (the number of bits required for coding) of each of the difference value D and the difference value D ″ input from the difference value calculators 5a and 5b, A prediction method capable of encoding with a smaller number of bits is selected, and the identification signal is output as an encoding mode.If the mode selector 21 determines that the code length when encoding the difference value D is short, Encoding mode "this frame"
Is determined to have a short code length when the difference value D ″ is encoded, the encoding mode “reference frame” is output to the switch 22 and the encoder 8a.

The switching unit 22 responds to the output of the mode selector 21 to change the difference value D output from the difference value calculator 5a in the encoding mode “the current frame” to the encoding mode “reference frame”. For example, the difference value D "output from the difference value calculator 5b is output to the encoder 8b.
The encoding mode selected by the mode selector 21 is encoded,
The encoder 8b encodes the output difference value and outputs the encoded difference values as encoded signals 9a and 9b, respectively. The encoding performed by the image encoding apparatus according to the second embodiment is lossless encoding that does not involve a rounding error. As described above, the input image signal 1 is stored in a memory as a pixel value that has been encoded and decoded up to a changed pixel. 3 is stored.

The above operation will be specifically described with reference to FIG. FIG. 4 is a model of a binary image signal in which each pixel value is represented by white and black rectangles, similarly to FIG. 2 used for description in the first embodiment. Similarly to the above, for simplicity of description, the processing procedure will be described assuming that one pixel is sequentially processed. 4A shows an input signal, and FIG. 4B shows an image signal of a reference frame. FIG. 4C is a diagram for explaining prediction based on the frame. P1 is a detected changed pixel detected by the changed pixel detector 2 as in the first embodiment. It is assumed that Pc is a decoded final pixel position, Pu is a pixel having a change in the pixel value of a scanning line at an upper position, and a coarse hatched portion represents a pixel that has not been encoded yet. Change pixel predictor 4
a performs prediction using a correlation based on the changed pixel Pu of the scanning line at the upper position using the same method as the prediction of the changed pixel in the first embodiment, and is at the same horizontal position as Pu.
Let P0 be a predicted change pixel based on the frame.

Assuming that the image signal of the reference frame in FIG. 4B has been subjected to motion compensation by the motion compensator 20, the changed pixel predictor 4b obtains a predicted changed pixel Pr. Therefore, the difference value D by the difference value calculator 5a is P1 and P0
And the difference value D "by the difference value calculator 5b.
Is 0, which is the difference between P1 and Pr. As for the setting of the image coding apparatus according to the second embodiment, similar to the first embodiment, if coding is performed to assign a code having a shorter code length as the difference value from P0 is smaller, the difference between P1 and P0 is assumed. Will result in a shorter code length when coding the difference between Pr and P1 than when coding. Therefore, the selection of the mode selector 21 results in a “reference frame” that outputs the difference value D ″, and the encoding mode “reference frame” and the difference value D ″ are encoded, and the image of the second embodiment is encoded. Fig. 4E shows a decoding result obtained by decoding the encoded signal, which is an encoded signal output from the encoding device.

As described above, in the image coding apparatus according to the second embodiment, the memory 3, the change pixel predictors 4a and 4b
, Difference value calculators 5a and 5b, and a motion compensator 20, the prediction based on the frame and the prediction with motion compensation based on the reference frame are performed. And the difference between the detection result and
Mode selector 21, switcher 22, encoder 8
a and 8b, the difference between the prediction based on the frame and the prediction based on the motion-compensated reference frame is compared, and the code having the minimum code length is selected and the code is selected. Therefore, by utilizing the pixel correlation between frames, the number of bits required for encoding can be significantly reduced. In the image coding apparatus according to the second embodiment, it is assumed that the input signal 1 is input in units of blocks and the coding mode is selected in units of blocks, that is, based on the prediction by the frame in units of blocks. By encoding and reference frame,
It is possible to adaptively switch between coding based on prediction accompanied by motion compensation, and the above-described effects are obtained.
In the image coding apparatus according to the second embodiment, the changed pixel detector 2, the changed pixel predictors 4a, and 4b output the distance (the number of pixels) to the changed pixel. Is a change pixel, and "0" is a binary signal indicating two states of "the next pixel is not a change pixel".
And "1", and the difference value calculators 5a and 5b may calculate the difference value of the binary signal. However, in this case, instead of encoding the distance as described above, the outputs of the difference value calculators 5a and 5b are encoded for each pixel of the input signal 1. With such a setting, the outputs of the changed pixel detector 2 and the changed pixel predictors 4a and 4b are binary, so that the effect that the encoding process can be simplified can be obtained.

Embodiment 3 The image decoding device according to the third embodiment of the present invention provides a coded signal efficiently coded by the image coding device according to the second embodiment,
It performs appropriate decryption. FIG. 5 is a block diagram illustrating a configuration of an image decoding apparatus according to Embodiment 3 of the present invention. In the figure, 30a and 30b are coded signals corresponding to the coded signals 9a and 9b in FIG.
A signal obtained by coding the coding mode and a signal obtained by coding the difference value. Decoders 31a and 31b decode a signal obtained by coding the coding mode and a signal obtained by coding the difference value to obtain a prediction mode signal and a decoded difference value. Reference numeral 32 denotes a switch that switches the predicted value of the changed pixel in accordance with the prediction mode signal acquired by the decoder 31a. 34 is a decoded image signal. The memory 3, the changing pixel decoder 10, and the difference value adder 11 are the same as those in FIG. 1, and the motion compensator 20 is the same as that in FIG. The description is omitted here because it is similar.

The operation of the image decoding apparatus according to the third embodiment shown in FIG. 5 configured as described above will be described. In the image coding apparatus according to Embodiment 2, the signal 9a obtained by coding the selected coding mode is the input signal 3
0a is input to the image decoding apparatus according to the third embodiment, and is decoded by the decoder 31a, thereby obtaining a prediction mode signal indicating the “current frame” or the “reference frame”. The decoder 31a outputs the prediction mode signal to the switch 32. In the image encoding device according to the second embodiment, the signal 9b obtained by encoding the selected difference value is input to the image decoding device according to the third embodiment as an input signal 30b, and is decoded by the decoder 31b. As a result, a decoding difference value is obtained. The decoder 31b adds the decoded difference value to the difference value adding means 11
Output to

On the other hand, the changed pixel predictor 4a reads out the decoded reference image of the frame stored in the memory 3, predicts the changed pixel based on the image signal, and predicts the result based on the frame. It outputs to the switch 32 as a changed pixel. Further, the motion compensator 20 performs motion compensation on the decoded image of the reference frame stored in the memory 3, and the change pixel predictor 4b calculates a change pixel of the input signal based on the motion compensated pixel. And outputs the result to the switch 32 as a predicted change pixel based on the reference frame.

The switching unit 22 that has output the respective predicted changed pixels from the changed pixel predictors 4a and 4b performs switching according to the input prediction mode signal. Therefore, if the input prediction mode signal indicates the “current frame”, the switch 22 changes the change pixel predictor 4.
If the input prediction mode signal indicates a "reference frame", a predicted change pixel based on the reference frame output from the change pixel predictor 4b is selected. And outputs the result to the difference value adding means 11.

The difference value adding means 11 calculates a changed pixel by adding the decoded difference value obtained from the decoder 31b to the predicted changed pixel obtained from the switch 22 and calculates the changed pixel. Output to the decoder 10. The changed pixel decoder 10 decodes a pixel value between the predicted changed pixel of the changed pixel prediction unit 4 a and the changed pixel obtained from the difference value adding unit 11 based on the changed pixel. The result of this decoding is input to and stored in the memory 3, and is also used as the decoded image signal 34 in the third embodiment.
Is output from the image decoding device. For example, when the coded signal described with reference to FIG. 4 in the second embodiment is used as an input signal, a decoding result shown in FIG. 4E is obtained.

FIG. 6 is a block diagram showing a configuration of an image decoding apparatus according to an application of the third embodiment. The difference from the image decoding device shown in FIG. 5 is that the switching device 33 has two difference value adding means 11a and 11b.
The point is that the output of the difference value adding means 11a and 11b is switched instead of the output of the change pixel prediction means 4a and 4b. Even in such a configuration, it is possible to appropriately decode the coded signal output from the image coding apparatus according to Embodiment 2 in accordance with the coding mode at the time of the coding. Further, a similar effect can be obtained even when a plurality of changing pixel decoders 10 are provided and the position of the switch is set to a position for receiving the outputs of the plurality of changing pixel decoders 10.

As described above, in the image decoding apparatus according to the third embodiment, the decoder 31a for decoding the coded signal in the coding mode and the decoder 31b for decoding the coded signal of the difference value A changing pixel prediction unit 4a for predicting a changing pixel based on the frame,
It comprises a changing pixel predicting unit 4b for predicting a changing pixel with motion compensation, a difference value adding unit 11 for performing a decoding process based on the predicted changing pixel, and a changing pixel decoder 10, and is obtained by the decoder 31a. In accordance with the prediction mode to be performed, the switch performs switching, in the prediction mode corresponding to the encoding mode at the time of encoding, decoding using the prediction value based on the frame, and the prediction value based on the reference frame. The decoding to be used is adaptively switched, and the coded signal efficiently coded in the second embodiment can be appropriately decoded.

In the second and third embodiments,
A plurality of frames may be prepared as reference frames, and three or more prediction modes may be used. Also, in the third embodiment, when an encoding mode is selected in units of blocks and an encoded signal is processed, a signal is input in units of blocks, and a prediction mode is acquired for each block. By performing processing corresponding to the encoding mode, it is possible to appropriately decode.

Embodiment 4 The image encoding apparatus according to Embodiment 4 of the present invention performs processing by adaptively switching between encoding based on prediction by horizontal scanning and encoding based on prediction by vertical scanning. FIG. 7 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 4 of the present invention. In the figure, 40a and 40b are horizontal scanners, and 41a and 41b are vertical scanners. Other symbols are the same as those in FIG. 3 and the description is the same as in the second embodiment, and thus will not be repeated here.

The operation of the thus configured image encoding apparatus according to the fourth embodiment will be described. When an input signal 1, which is a binary image signal, is input to the apparatus, the input signal 1 is scanned in the horizontal direction by a horizontal scanner 40a and input to a changing pixel detector 2a, and a vertical scanner 41a
Is scanned in the vertical direction and is input to the changing pixel detector 2b. Further, the input signal 1 is also input to the memory 3 and is stored in the memory 3 to be used as an encoded and decoded reference image in the frame. The change pixel detector 2a receives the input signal 1 scanned in the horizontal direction as an input, and detects a pixel whose binary pixel value changes. The change pixel detector 2b receives an input signal 1 scanned in the vertical direction as an input and detects a pixel whose binary pixel value changes. The changed pixel detectors 2a and 2b use the detection result as a detected changed pixel as the difference value calculators 5a and 5b.
b.

On the other hand, the horizontal scanner 40b reads the encoded and decoded reference image of the frame stored in the memory 3 and scans it in the horizontal direction to change the pixel.
To enter. The change pixel predictor 4a predicts a change pixel,
The result is output to the difference value calculator 5a as a predicted change pixel. Then, the difference value calculator 5a subtracts the predicted change pixel from the detected change pixel to obtain a difference value Dh by horizontal scanning. The output Dh of the difference value calculator 5a corresponds to the prediction error of the changed pixel predicted by the horizontal scanning, and the difference value calculator 5a compares the difference value Dh with the mode selector 21 and the switch 22. Output to On the other hand, the vertical scanner 41b reads out the encoded and decoded reference image of the frame stored in the memory 3, scans in the vertical direction, and inputs it to the change pixel predictor 4b. The changed pixel predictor 4b predicts a changed pixel and outputs the result to the difference value calculator 5b as a predicted changed pixel. Then, the difference value calculator 5b subtracts the predicted change pixel from the detected change pixel, and obtains a difference value Dv by vertical scanning. Difference value calculator 5b
Is equivalent to the prediction error of the changed pixel predicted by the vertical scanning, and the difference value calculator 5b
The difference value Dv is output to the mode selector 21 and the switch 22.

The mode selector 21 calculates the difference value Dh and the difference value Dv input from the difference value calculators 5a and 5b.
The code length (the number of bits required for encoding) when each is encoded is compared, a prediction method that can be encoded with a smaller number of bits is selected, and the identification signal is output as an encoding mode. When the mode selector 21 determines that the code length when encoding the difference value Dh is short, the mode selector 21 determines that the encoding mode is “horizontal direction” and that the code length when encoding the difference value Dv is short. Outputs the encoding mode “vertical direction” to the switching unit 22 and the encoder 8a. Switch 22
Corresponds to the output of the mode selector 21, the difference value Dh output from the difference value calculator 5 a in the coding mode “horizontal direction”, and the difference value calculator 5 b in the coding mode “vertical direction”. Is output to the encoder 8b.
The encoder 8a encodes the encoding mode selected by the mode selector 21, and the encoder 8b encodes the output difference value and outputs the difference values as encoded signals 9a and 9b, respectively.

The encoding by the image encoding apparatus according to the fourth embodiment is lossless encoding without rounding error.
As described above, the input image signal 1 is stored in the memory 3 as a pixel value obtained by encoding and decoding the pixels up to the changed pixel. FIG. 8 is a block diagram of the image encoding apparatus according to the fourth embodiment.
FIG. 5 is a diagram for explaining scanning direction switching. The image signal has a correlation in the horizontal and vertical directions, and even in the image coding method according to the related art, compression has been achieved by utilizing such a correlation. Then, regarding the use of the correlation according to the conventional technique, encoding is performed based on only the correlation in either the horizontal direction or the vertical direction, for example, as seen in the case of MMR. . However, when the image is partially viewed, one of the horizontal and vertical correlations may be stronger than the other. For example, when the correlation in the horizontal direction is stronger than the correlation in the vertical direction as shown in FIG. 8, the prediction error of the pixel whose pixel position is changed becomes smaller based on the prediction in the horizontal direction than on the prediction in the vertical direction. , It is possible to further improve the coding efficiency. Therefore, by changing the scanning direction according to the nature of the image and switching between the vertical prediction and the horizontal prediction, the coding efficiency can be greatly improved.

As described above, in the image coding apparatus according to the fourth embodiment, the horizontal scanners 40a and 40b, the vertical scanners 41a and 41b, and the change pixel detectors 2a and 2b are used.
b, the memory 3, the change pixel predictors 4a and 4b,
With the provision of the difference value calculators 5a and 5b, prediction by horizontal scanning and scanning prediction in the vertical direction are performed, and a difference value between each predicted value and a detection result is obtained. By providing the selector 21, the switch 22, and the encoders 8a and 8b, the difference between the prediction by horizontal scanning and the prediction by vertical scanning is compared, Since the minimum length can be selected and encoded, the number of bits required for encoding is greatly reduced by utilizing local changes in the horizontal correlation and vertical correlation of an image. be able to.

In the image coding apparatus according to the fourth embodiment as well, it is assumed that the input signal 1 is input in block units, and that the coding mode is selected in block units. The coding based on the prediction based on the scanning and the coding based on the prediction based on the vertical scanning can be adaptively switched, and the above-described effects are obtained. Also, in the image coding apparatus according to the fourth embodiment, similarly to the second embodiment, the changed pixel detector 2,
It is also possible that the change pixel predictors 4a and 4b do not output the distance (the number of pixels) to the change pixel but output a binary signal indicating the change state of the pixel. It is possible to reduce.

Embodiment 5 An image decoding device according to the fifth embodiment of the present invention provides a coded signal efficiently coded by the image coding device according to the fourth embodiment,
It performs appropriate decryption. FIG. 9 is a block diagram showing a configuration of an image decoding apparatus according to Embodiment 5 of the present invention. In this figure, reference numerals 40b and 41b are the same as those in FIG. 7, and other reference numerals are the same as those in FIG. 5, and the description is the same as that of the fourth and third embodiments, respectively. .

The operation of the image decoding apparatus according to the fifth embodiment configured as described above will be described. In the image coding apparatus according to the fourth embodiment, the signal 9a obtained by coding the selected coding mode is input to the image decoding apparatus according to the fifth embodiment as an input signal 30a, and is decoded by the decoder 31a. As a result, a prediction mode signal indicating “horizontal direction” or “vertical direction” is obtained. The decoder 31a switches the prediction mode signal to the switch 32
Output to In the image encoding device according to the fourth embodiment, the signal 9b obtained by encoding the selected difference value is input to the image decoding device according to the fifth embodiment as an input signal 30b, and is decoded by the decoder 31b. As a result, a decoding difference value is obtained. The decoder 31b outputs the decoded difference value to the difference value adding means 11.

On the other hand, the horizontal scanner 40b reads the encoded and decoded reference image of the frame stored in the memory 3 and scans it in the horizontal direction to change the pixel.
To enter. The change pixel predictor 4a predicts a change pixel,
The result is output to the switch 22 as a predicted change pixel. On the other hand, the vertical scanner 41b reads out the encoded and decoded reference image of the frame stored in the memory 3, scans in the vertical direction, and inputs it to the change pixel predictor 4b. The change pixel predictor 4b predicts a change pixel and outputs the result to the switch 22 as a predicted change pixel.

The switching unit 22, which has output the respective predicted changed pixels from the changed pixel predictors 4a and 4b, switches according to the input prediction mode signal. Accordingly, if the input prediction mode signal indicates the “horizontal direction”, the switching unit 22 determines the predicted change pixel based on the horizontal scanning output from the change pixel predictor 4a and the input prediction mode signal If it indicates “vertical direction”, the predicted change pixel based on the vertical scanning output from the change pixel predictor 4 b is selected and output to the difference value adding means 11.

The difference value adding means 11 calculates a changed pixel by adding the decoded difference value obtained from the decoder 31b to the predicted changed pixel obtained from the switch 22, and calculates the result as a changed pixel. Output to the decoder 10. The changed pixel decoder 10 decodes a pixel value between the predicted changed pixel of the changed pixel prediction unit 4 a and the changed pixel obtained from the difference value adding unit 11 based on the changed pixel. The result of this decoding is input to and stored in the memory 3, and is used as the decoded image signal 34 in the fifth embodiment.
Is output from the image decoding device.

As described above, in the image decoding apparatus according to the fifth embodiment, the decoder 31a for decoding the coded signal in the coding mode and the decoder 31b for decoding the coded signal of the difference value are provided. A changing pixel prediction unit 4a for predicting a changing pixel based on horizontal scanning, a changing pixel prediction unit 4b for predicting a changing pixel based on vertical scanning, and a difference value adding unit for performing a decoding process based on the predicted changing pixel 11 and the changing pixel decoder 10, and the switch performs switching in accordance with the prediction mode obtained by the decoder 31a, so that in the prediction mode corresponding to the encoding mode at the time of encoding, The decoding using the prediction value based on the horizontal scanning and the decoding using the prediction value based on the vertical scanning are adaptively switched to perform decoding efficiently. It is possible to properly decode the Goka signal.

In the fifth embodiment, an image decoding apparatus having a configuration similar to the configuration shown in FIG. 5 in the third embodiment has been described. However, in the third embodiment, an image decoding apparatus shown in FIG. It is also possible to adopt a configuration that conforms to the configuration, or a configuration in which the switch receives the output of the changing pixel decoder, as described in the embodiment. Decryption can be performed. Also, in the fifth embodiment, when an encoding mode is selected in units of blocks and an encoded signal is processed, a signal is input in units of blocks, and a prediction mode is acquired for each block. By performing the processing corresponding to the encoding mode, it is possible to appropriately decode.

Embodiment 6 FIG. The image coding apparatus according to the sixth embodiment of the present invention efficiently codes a multi-level image signal. FIG. 10 is a block diagram showing a configuration of an image encoding device according to Embodiment 6 of the present invention. In the figure, an input signal 1a is input as a multi-level image signal to the image coding apparatus according to the sixth embodiment. 8a and 8b are encoders. As described above, the point that a multi-level signal is input and processed and the point that the configuration is provided with two encoders are different from the first embodiment, and the other points are the same as those in FIG. Since it is the same as the first embodiment, the description is omitted here.

The operation of the image coding apparatus according to the sixth embodiment configured as described above will be described. When the input signal 1a is input, the changing pixel detector 2 calculates the pixel value of the final encoding / decoding position with respect to the multi-valued input signal,
The pixel value of the position subsequent to the position is compared with the pixel value, and “change” or “no change” is determined for each pixel. Then, the number of changed pixels, which is the number of pixels determined to be “changed”, is calculated, and the number of changed pixels is compared with a predetermined value. Here, it is assumed that the predetermined value is 60. A pixel which has been determined to be “changed” and whose number of changed pixels is equal to or greater than 60 is determined to be a changed pixel, and the pixel value and position of the changed pixel are used as a detected changed pixel as a difference value calculator 5 and a changed pixel decoder 10. , And to the encoder 8a.

The changed pixel predictor 4 reads the encoded and decoded reference image of the frame stored in the memory 3 and predicts a changed pixel based on the read reference image, and uses this prediction as a predicted changed pixel. Difference value calculator 5, Difference value adder 1
1 and output to the changing pixel decoding means. The difference value calculator 5 outputs a difference value obtained by subtracting the predicted change pixel from the detected change pixel to the encoder 8b and the difference value adder 11. The difference value adder 11 adds the input prediction change pixel and the difference value and outputs the result to the change pixel decoder 10. The change pixel decoder 10 determines the pixel value and the change up to the change pixel based on the input. The pixel value of the pixel is decoded and stored in the memory 3. The encoders 8a and 8b encode the input pixel values of the changed pixels and the difference values, respectively, and
a and 9b are output. Thus, the sixth embodiment
In the image coding apparatus according to the first embodiment, in the same configuration as in the first embodiment, the presence or absence of a change is checked for each pixel,
By calculating the number of pixels that are determined to be “changed”, and determining the pixels whose number is equal to or greater than the threshold value to be determined to be “changed” as changed pixels, not only the binary image but also multi-valued Similar encoding can be performed on an image.

Embodiment 7 FIG. An image decoding apparatus according to the seventh embodiment of the present invention is to decode a coded signal coded by the image coding apparatus according to the sixth embodiment to obtain a multi-valued image signal. . FIG. 11 is a block diagram showing a configuration of an image decoding device according to Embodiment 7 of the present invention. In the figure, a decoder 31a decodes a coded signal obtained by coding a pixel value of a changed pixel, and a decoder 31b decodes a coded signal obtained by coding a prediction difference value. . The other parts are the same as those in FIG.

The operation of the image decoding apparatus according to the seventh embodiment, configured as described above, will be described. In the image coding apparatus according to the sixth embodiment, the signal 9a obtained by coding the pixel value of the changed pixel is input to the image decoding apparatus according to the seventh embodiment as an input signal 30a,
By decoding at a, a decoded pixel value is obtained, and this decoded pixel value is input to the changing pixel decoder 10. In the image coding apparatus according to Embodiment 6, the signal 9b obtained by coding the prediction difference value is the input signal 30b.
Is input to the image decoding apparatus according to the seventh embodiment, and is decoded by the decoder 31b to obtain a decoding difference value. The decoding difference value is input to the difference value adder 11.

On the other hand, the changed pixel predictor 4 reads the decoded reference image stored in the memory 3, predicts a changed pixel based on the image signal, and uses the result as a predicted changed pixel to decode the changed pixel. And a difference value adder 11. The difference value adder 11 adds the input predicted change pixel and the difference value, and outputs the result to the change pixel decoder 10.
The changing pixel decoder 10 decodes the pixel value up to the changing pixel and the pixel value of the changing pixel based on the input, outputs the decoded value as the multi-valued image signal 34, and stores it in the memory 3. As described above, in the image decoding device according to the seventh embodiment, the decoder 31a that decodes the encoded signal obtained by encoding the pixel value of the changed pixel and the encoding that encodes the prediction difference value With the provision of the decoder 31b for decoding the signal, the multi-level image signal is obtained by appropriately decoding the coded signal coded by the image coding apparatus according to the sixth embodiment. Becomes possible.

Embodiment 8 FIG. The image coding apparatus according to the eighth embodiment of the present invention uses an image signal composed of a transmittance signal indicating a ratio when combining images and a pixel value signal as an input signal, It encodes the signal. FIG. 12 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 8 of the present invention. In the figure, reference numeral 60a denotes a pixel value signal, and 60b denotes a transmittance signal, which constitutes an image signal, and is input to the image encoding apparatus according to the eighth embodiment as an input signal. Reference numeral 61 denotes a memory which temporarily stores data such as an encoded and decoded image signal used as a reference image. 62a and 62b are motion detectors that perform motion detection on the reference image and output a motion vector.
63a and 63b are motion compensators, which perform motion compensation on the image signal of the encoded and decoded reference frame to generate a reference pixel value. 64a and 64b are difference value calculators that calculate the difference between the input signal and the signal with motion compensation and output the difference value. Encoders 65a and 67b encode motion vectors. 67a
And 65b are encoders for encoding the difference values. 6
6a and 68b are coded signals obtained by coding motion vectors. 67a and 65b are coded signals obtained by coding the difference values.

The operation of the image coding apparatus according to the eighth embodiment configured as described above will be described. The image signal includes a pixel value signal 60a and a transmittance signal 60b.
This is input to the image encoding device according to the eighth embodiment. Here, the transmittance signal is a signal shown in FIG. 53 (b) used in the description of the related art, and represents a ratio at which each pixel is combined when combined with another image. Things. The pixel value signal 60a is stored in the memory 61, the motion detector 6
2a and the difference value calculation means 64a, and the transmittance signal 60b is input to the memory 61, the motion detector 62b, and the difference value calculation means 64b.

The motion detectors 62a and 62b perform motion detection by comparing the input signal with the coded pixel value of the reference image read from the memory 61, and calculate the respective signals. Get the motion vector of the signal. The motion vector of the pixel value signal obtained by the motion detector 62a is output to the encoder 65a, the motion compensator 63a, and the memory 61. Motion compensator 6
3a reads the pixel value indicated by the motion vector of the pixel value signal from the memory 61 and outputs the motion compensation value of the pixel value signal to the difference value calculator 64a.

The difference value calculator 64a calculates the input pixel value signal,
The difference value of the motion compensation value is obtained by calculation, and is output to the encoder 67a. The motion vector of the pixel value signal is encoded by an encoder 65a to become an encoded signal 66a,
The difference value is encoded by the encoder 67a to generate an encoded signal 68.
a. Similarly, the motion vector of the transmittance signal acquired by the motion detector 62b is output to the encoder 67b, the motion compensator 63b, and the memory 61. Motion compensator 63
b performs motion compensation on the transmittance signal and outputs the obtained motion compensation value to the difference value calculator 64a. Then, the difference value calculator 64b outputs the obtained difference value to the encoder 67a as in the case of 64a. Similarly to the pixel value signal, the motion vector of the transparency signal is encoded by an encoder 67b to become an encoded signal 68b, and the difference value is encoded by an encoder 65b to become an encoded signal 66b. The eighth embodiment is an example of lossless encoding, in which an encoded input signal is stored in a memory 61 and used for encoding a subsequent image signal (not shown).

As described above, in the image coding apparatus according to the eighth embodiment, the motion detector 62a for processing the pixel value signal 60a, the motion compensator 63a, the difference value calculator 64a, the encoder 65a, and the code And the transmittance signal 60
b, a motion detector 62b, a motion compensator 63b,
Difference value calculator 64b, encoder 65b, and encoder 6
7b, it is possible to separately perform motion detection on each of the pixel value signal 60a and the transmittance signal 60b to obtain a motion vector, and perform motion compensation.

As described in the description of the prior art, in the conventional image coding, when an image composed of shape information and pixel value information is encoded, the shape information used for synthesizing the image is as follows. In order to improve coding efficiency, motion compensation coding of shape information is performed using a motion vector of pixel value information. Therefore, when encoding a signal such as the input image signal according to the eighth embodiment, the motion compensation encoding of the transparency signal is performed using the motion vector of the pixel value signal. However, although the transmittance signal is a signal indicating the shape of the object, its motion vector does not always match the motion vector of the pixel value signal. An example is the case where the shape of the rotating disk is unchanged, but the pattern drawn on the disk moves. Therefore, in such a case, since the difference between the motion vector of the pixel value signal and the motion vector of the transparency signal is large, the motion error when the motion compensation of the transparency signal is performed using the motion vector of the pixel value signal is performed. Becomes large, the coding length of the difference value becomes long, and the coding efficiency decreases.

On the other hand, the image coding apparatus according to the eighth embodiment performs motion compensation on the transparency signal by using a motion vector detected separately from the motion vector of the pixel value signal. The input transparency signal can be more accurately approximated by the motion compensation signal, and the motion compensation error is reduced, so that the coding efficiency is improved. In the image coding apparatus according to the eighth embodiment as well, it is assumed that the input signal is input in units of blocks, and the settings can be made such that motion compensation and coding are performed in units of blocks. .

Embodiment 9 FIG. The image coding apparatus according to the ninth embodiment of the present invention, similarly to the eighth embodiment, takes an image signal including a transmittance signal and a pixel value signal as an input signal,
This input signal is encoded with reference to a reference image. FIG. 13 is a block diagram showing a configuration of an image encoding device according to Embodiment 8 of the present invention. In the figure,
The reference numerals are the same as those in FIG. 12, and the description is the same as in the eighth embodiment. In the image coding apparatus according to the ninth embodiment, the motion detector 62a for the pixel value signal 60a outputs the obtained motion vector of the pixel value signal to the motion detector 62b for the transparency signal 60b, and the motion detector 62b
Is different from the image coding apparatus according to the eighth embodiment in that the motion detection of the transmittance signal is performed in the vicinity of the motion vector of the input pixel value signal.

The operation of the image coding apparatus according to the ninth embodiment is the same as that of the eighth embodiment except that the motion detector 62a performs the above-described output and the motion detector 62b performs the above-described detection. The operation is similar to that of the first embodiment. As described above, in the image encoding device according to the ninth embodiment, the
The motion detector 62a for the pixel value signal 60a outputs the motion vector of the acquired pixel value signal to the motion detector 62b for the transmittance signal 60b, and the motion detector 62b Since the motion detection of the transmittance signal is performed in the vicinity of the motion vector, the motion detection of the pixel value signal is used for the motion detection of the transmittance signal.

Although the motion vector between the pixel value signal and the transmittance signal may be greatly different from each other as in the example shown in the eighth embodiment, they are almost the same in many images. Therefore, when detecting the motion vector of the transparency signal, if the motion vector of the transmittance signal is detected only in the vicinity of the motion vector of the pixel value signal, it is necessary for the motion detection as compared with the case where the motion vector of the transparency signal is performed completely independently. It is possible to reduce the number of necessary calculations. As compared with the case where motion detection is performed independently of the pixel value signal, the number of selectable motion vectors is limited, so that the motion compensation error of the transmittance signal slightly increases, but the ratio is slightly small. is there. Therefore, in the image coding apparatus according to the ninth embodiment, similar to the eighth embodiment, by performing appropriate motion compensation on each signal,
The encoding efficiency can be improved, and the number of calculations for motion detection can be reduced.

In the image encoding apparatus according to the ninth embodiment, the motion vector of the pixel value signal is used to detect the motion of the transparency signal. However, the image encoding apparatus according to the eighth embodiment shown in FIG. The motion detector 62b for the transparency signal 60b outputs the motion vector of the acquired transparency signal to the motion detector 62a for the pixel value signal 60a based on the configuration of the conversion device, and the motion detector 62a In the vicinity of the motion vector of the degree signal, it is also possible to perform the motion detection of the pixel value signal, and to detect the motion of the pixel value signal, it is also possible to adopt a configuration in which the result of the motion detection in the transparency signal is used, Again, the number of calculations for motion detection can be reduced. Further, it is similar to the eighth embodiment in that encoding can be performed in block units by setting.

Embodiment 10 FIG. Embodiment 10 of the present invention
, As in the eighth and ninth embodiments, takes an image signal composed of a transmittance signal and a pixel value signal as an input signal, and encodes the input signal with reference to a reference image. Things. FIG. 13 shows Embodiment 10 of the present invention.
1 is a block diagram illustrating a configuration of an image encoding device according to the present invention.
In the figure, reference numeral 70 denotes a motion vector difference calculator that obtains a difference vector between a motion vector of a pixel value signal obtained from the motion detector 62a and a motion vector of a transmittance signal obtained from the motion detector 62b. . Encoder 6
7b encodes the motion vector of the transparency signal in the eighth embodiment, but in the tenth embodiment, the difference value calculator 70b encodes the motion vector.
Encodes the difference vector of the motion vector acquired by.
Other symbols are the same as those in FIG. 12, and the description is the same as in the eighth embodiment. Regarding the operation of the image coding apparatus according to the tenth embodiment, the motion detectors 62a and 62b output the motion vector to the difference value calculator 70, and the difference value calculator 70 Gasifier 67b
, And the operation is the same as that of the eighth embodiment except that the encoder 67b encodes the difference vector of the motion vector.

As described above, the image coding apparatus according to the tenth embodiment has a configuration in which the motion vector difference value calculator 70 is added based on the configuration of the image coding apparatus according to the eighth embodiment. Instead of encoding the motion vector of the transparency signal, a difference vector between the motion vector of the pixel value signal and the motion vector of the transparency signal is encoded. As described in the ninth embodiment, since the motion vectors of both signals often have a correlation, if the difference vector between the motion vectors of both signals is encoded, the frequency of occurrence of the difference vector is concentrated near the zero vector. As a result, by performing variable length coding in which a code having a short code length is assigned to a difference vector near the 0 vector, coding efficiency is improved, and coding can be performed with a smaller number of bits.

In the image coding apparatus according to the tenth embodiment, instead of coding the motion vector of the transparency signal, the difference vector between the motion vectors of the two signals is coded. It is also possible to output the difference vector obtained by the unit 70 to the encoder 65b instead of the encoder 67b. Instead of encoding the motion vector of the pixel value signal, it is possible to encode the difference vector of the motion vector of both signals. Thus, a similar effect can be obtained. Further, it is similar to the eighth embodiment in that encoding can be performed in block units by setting.

Embodiment 11 FIG. Embodiment 11 of the present invention
The image decoding apparatus according to the present invention performs appropriate decoding on the encoded signal efficiently encoded by the image encoding apparatus according to the eighth embodiment. FIG. 15 is a block diagram showing a configuration of an image decoding device according to Embodiment 11 of the present invention. In the figure, 82a and 82b are:
This is a coded signal corresponding to the coded signals 68a and 66b in FIG. 12, and is a signal obtained by coding a difference value between each of the pixel value signal and the transmittance signal. 80a and 80b
Is a coded signal corresponding to the coded signals 66a and 68b in FIG. 12, and is a signal obtained by coding the motion vector of each of the pixel value signal and the transmittance signal. Decoders 83a and 83b decode the coded signals of the difference values of the pixel value signal and the transmittance signal, and output decoded difference values of the pixel value signal and the transmittance signal. 81
Decoders a and 81b decode the coded signals of the motion vectors of the pixel value signal and the transparency signal, and output decoded motion vectors of the pixel value signal and the transparency signal. Reference numeral 61 denotes a memory which temporarily stores data such as an encoded and decoded image signal used as a reference image. 63a and 63b are motion compensators that perform motion compensation using decoded motion vectors. 84
Reference numerals a and 84b denote difference value adders, which perform addition processing using the decoded difference values. 85a and 85b are decoded image signals.

The eleventh embodiment configured as described above
The operation of the image decoding apparatus according to the above will be described. In the image coding apparatus according to the eighth embodiment, signals 68a and 66b obtained by coding the difference values between the pixel value signal and the transmittance signal are used as the input signals 82a and 82b in the image decoding according to the eleventh embodiment. Input to the device and decoded by decoders 83a and 83b,
The decoded difference values of the pixel value signal and the transmittance signal are output to difference value adders 84a and 84b. Further, in the image encoding device according to Embodiment 8, the pixel value signal,
66a and 68b obtained by encoding the motion vector of each of the input signals 80a and 80b
Is input to the image decoding apparatus according to the eleventh embodiment, and is decoded by the decoders 81a and 81b.
Pixel value signal, and the decoded motion vector of the transparency signal,
It is output to the motion compensators 63a and 63b.

The motion compensators 63a and 63b store the pixel values indicated by the input motion vectors in the memory 6 respectively.
1 and performs motion compensation, and outputs the motion compensation value to the difference value adders 84a and 84b. The difference value adders 84a and 84b respectively perform an addition process on the input decoded difference value and the motion compensation value, and
5a and 85b, and the memory 61
Will be stored.

As described above, in the image decoding apparatus according to the eleventh embodiment, the decoder 81a, the decoder 83a, and the motion compensator 63 for processing the coded signal of the pixel value signal.
a, a difference value calculator 84a, a decoder 81b for processing an encoded signal of a transparency signal, and a decoder 83b, a motion compensator 63b, and a difference value calculator 84b, so that a pixel value signal Of the coded signals 80a and 82a and the coded signals 80b and 82b of the transparency signal can be separately decoded, and an image signal can be obtained by performing appropriate decoding. Becomes possible.

In the image decoding apparatus according to the eleventh embodiment, the coded signal obtained by the image coding apparatus according to the eighth embodiment is decoded. Similarly, the encoded signal obtained in can be appropriately decoded. Further, in the eighth or ninth embodiment, for an encoded signal input and encoded in block units,
By inputting in block units and setting for decoding, decoding can be performed appropriately.

Embodiment 12 FIG. Embodiment 12 of the present invention
The image decoding apparatus according to the present invention performs appropriate decoding on the encoded signal efficiently encoded by the image encoding apparatus according to the tenth embodiment. FIG. 16 is a block diagram showing a configuration of an image decoding device according to Embodiment 12 of the present invention. In the figure, reference numeral 86 denotes a motion vector difference value adder, which performs a process of adding a decoded motion vector and a decoded difference motion vector. The other reference numerals are the same as those in FIG. 15 and the description is the same as in the eleventh embodiment.

The twelfth embodiment constructed as described above
The operation of the image decoding apparatus according to the above will be described. The decoder 81a converts the decoded motion vector of the pixel value signal obtained by decoding the input signal 80a into a motion compensator 63a.
And the motion vector difference value adder 86
Also output to The decoder 80b does not receive the coded signal of the motion vector of the transparency signal as in the case of the eleventh embodiment, but the coded signal 68b of the differential motion vector of the tenth embodiment (see FIG. 14) is input, and the decoder 80b obtains a difference vector instead of obtaining the motion vector of the transparency signal by decoding as in Embodiment 11, and obtains the decoded differential motion vector Is output to the difference value adder 86. Since the decoded difference motion vector to be output is a difference vector between the motion vector of the pixel value signal and the motion vector of the transparency signal,
The difference vector is added to the decoded motion vector of the pixel value signal by the difference value adder 86, so that the motion vector of the transparency signal is obtained. The motion vector of the decoded transparency signal is calculated by the motion compensator 63b.
Is output to

The other operations are the same as the processing in the image decoding apparatus according to the eleventh embodiment. The decoded signal 85a of the pixel value signal and the decoded signal 85b of the transparency signal are output from the apparatus. As described above, the image decoding apparatus according to the twelfth embodiment has a configuration in which the motion vector difference value adder 86 is added based on the configuration of the image decoding apparatus according to the eleventh embodiment. And the decoded difference vector can be added, and the output coded signal of Embodiment 10 that outputs the coded signal of the difference vector as the coded signal can be appropriately decoded. Note that, as in the eleventh embodiment, it is possible to cope with the case where encoding is performed in block units in the tenth embodiment by setting.

Embodiment 13 FIG. Embodiment 13 of the present invention
The image coding apparatus according to the above, the shape signal indicating whether the shape of the object and the pixel value of each pixel is significant, and a pixel value signal, a block-shaped image signal having a shape as an input signal, reference This input signal is encoded with reference to an image. FIG. 17 shows Embodiment 13 of the present invention.
1 is a block diagram illustrating a configuration of an image encoding device according to the present invention.
In the figure, reference numeral 60a denotes a pixel value signal, and 60b denotes a shape signal, which constitute an image signal, and are respectively input as input signals to the image encoding apparatus according to the eighth embodiment. Decoders 69a and 69b decode the coded signals of the difference values output from the encoders 67a and 65b. Reference numerals 75a and 75b denote difference value adders, which add the decoded difference value to the motion compensation value and store the result in the memory 61. The other reference numerals are the same as those in FIG. 12 and the description is the same as in the eighth embodiment, so that the description is omitted here.

The thirteenth embodiment configured as described above
The operation of the image coding apparatus according to the first embodiment will be described. The block-shaped image signal having a shape, which is an input signal, is input to the image encoding apparatus according to the thirteenth embodiment as a pixel value signal 60a and a shape signal 60b. Here, the shape signal is the one shown in FIG. 53 used in the description of the related art, and is the binary information shown in FIG. 53 (c) or the multi-value information shown in FIG. 53 (d). In the case of multi-value information, it is the same as the transmittance signal in the eighth embodiment. In the image coding apparatus according to the thirteenth embodiment, the pixel value signal and the shape signal are coded by the same processing as in the eighth embodiment, and the coded signal 66a of the motion vector of the pixel value signal and the pixel An encoded signal 68a of the difference value of the value signal, an encoded signal 66b of the motion vector of the shape signal, and an encoded signal 68b of the difference value of the shape signal are obtained.

In the device according to the eighth embodiment, the coded signal is input to the memory 61. In the thirteenth embodiment, the coded difference values are supplied to the decoder 69, respectively.
a, and 69b, and the difference value adder 75a,
And 75b, and the difference value adders 75a and 75b
At b, the motion compensation values output from the motion compensators 63a and 63b are added to the sum and then input to the memory 61. Therefore, the reference image used for encoding is different from that of the eighth embodiment in that the reference image is encoded and decoded, and a motion compensation value is added.

As described above, in the image coding apparatus according to the thirteenth embodiment, based on the configuration of the image coding apparatus according to the eighth embodiment, the decoders 69a and 69b and the difference value adders 75a and 75b Is added to reduce the motion compensation error, as in the eighth embodiment, to improve the coding efficiency and to cause a slight increase in the processing load. However, by using a more appropriate signal that has been encoded and decoded as a reference image and to which a motion compensation value has been added, it is possible to further reduce the motion compensation error. The coded signal output by the image coding apparatus according to the thirteenth embodiment can be appropriately decoded by the image decoding apparatus according to the eleventh embodiment, as in the eighth embodiment. .

Embodiment 14 FIG. Embodiment 14 of the present invention
As in the thirteenth embodiment, the image encoding apparatus according to the first embodiment uses an image signal composed of a shape signal and a pixel value signal as an input signal, and encodes the input signal with reference to a reference image. FIG. 18 is a block diagram showing a configuration of an image encoding device according to Embodiment 14 of the present invention. In the figure, the reference numerals are the same as those in FIG. 17, and the description is the same as in the thirteenth embodiment. In the image coding apparatus according to the fourteenth embodiment, similar to the ninth embodiment, the pixel value signal 60a
, A motion detector 62a for the transmittance signal 60b
b, and the motion detector 62b differs from the image coding apparatus according to the thirteenth embodiment in that the motion detector 62b detects the motion of the transmittance signal in the vicinity of the motion vector of the input pixel value signal. .

The operation of the image coding apparatus according to the fourteenth embodiment is the same as that of the thirteenth embodiment except that the motion detector 62a performs the above-described output and the motion detector 62b performs the above-described detection. The operation is similar to that of the first embodiment. As described above, in the image coding apparatus according to the fourteenth embodiment, based on the configuration of the thirteenth embodiment, the motion detector 62a for the pixel value signal 60a uses the motion vector of the acquired pixel value signal as the motion for the shape signal 60b. The motion signal is output to the detector 62b, and the motion detector 62b performs the motion detection of the shape signal in the vicinity of the motion vector of the input pixel value signal. By using the result of motion detection in the pixel value signal for the detection, the number of calculations for motion detection can be reduced. Note that the configuration in which the motion vector of the pixel value signal is detected in the vicinity of the motion vector of the shape signal is similar to that of the ninth embodiment, and is obtained by the image encoding device of the fourteenth embodiment. As in the thirteenth embodiment, the coded signal can be decoded by the image decoding apparatus according to the eleventh embodiment.

Embodiment 15 FIG. Embodiment 15 of the present invention
Is an image encoding apparatus that encodes an input image signal composed of a shape signal and a pixel value signal with reference to a reference image, as in the thirteenth and fourteenth embodiments. It is. FIG. 19 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 15 of the present invention. In the figure, a motion vector difference calculator 70 is the same as that of the tenth embodiment shown in FIG. Also, the encoder 67b encodes the difference vector of the motion vector acquired by the difference value calculator 70 as in the tenth embodiment. Other symbols are the same as those in FIG. 17, and the description is the same as that of the thirteenth embodiment.

As for the operation of the image coding apparatus according to the fifteenth embodiment, the motion detectors 62a and 62b output the motion vector to the difference value calculator 70, and
0 is the same as that of the tenth embodiment in that the difference vector is obtained and output to the encoder 67b, and the encoder 67b encodes the difference vector of the motion vector. Same as 13. As described above, in the image coding apparatus according to Embodiment 15, Embodiment 13
By adding a motion vector difference value calculator 70 based on the configuration of the image encoding device of the above, instead of encoding the motion vector of the shape signal, the motion vector of the pixel value signal and the motion Encode the difference vector with the vector. Therefore, as in the tenth embodiment, by performing variable-length coding, it is possible to further improve coding efficiency.

It is to be noted that, in place of encoding the motion vector of the pixel value signal, the difference vector can be encoded as in the tenth embodiment. Also, the coded signal output by the image coding apparatus according to the fifteenth embodiment can be appropriately decoded by the image decoding apparatus according to the twelfth embodiment, as in the tenth embodiment. .

Embodiment 16 FIG. Embodiment 16 of the present invention
The image encoding apparatus according to the first embodiment encodes an image signal including a shape signal and a pixel value signal as an input signal and encodes the input signal with reference to a reference image, as in the thirteenth to fifteenth embodiments. is there. FIG. 20 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 16 of the present invention. In the figure, reference numeral 90 denotes a motion detection determiner which inputs an input shape signal 60b and a motion vector of a pixel value signal output from the motion detector 62a, and performs motion compensation of a shape signal by the motion vector of the pixel value signal. Whether the motion is detected or not is output to the motion detector 62b of the shape signal in accordance with the determination.

The sixteenth embodiment configured as described above
The operation of the image coding apparatus according to the first embodiment will be described. Regarding the processing of the pixel value signal 60a input to the image encoding device according to the sixteenth embodiment, the motion vector of the pixel value signal acquired by the motion detector 62a is
The processing is performed in the same manner as in the thirteenth embodiment, except that the pixel value signal is also output to 0.
And an encoded signal 68a of the difference value between the pixel value signals. On the other hand, the input shape signal 60b is first input to the motion detection / determination unit 90. The motion detection determiner 90 performs motion compensation on the input shape signal 60b using the motion vector of the input pixel value signal, compares the motion compensated shape signal with the input shape signal 60b, and Find out if you are. If they match, the motion vector of the pixel value signal is output to the motion detector 61b, and the motion detector 61b does not perform the motion detection on the shape signal, and uses the motion vector of the input pixel value signal. , The motion vector of the shape signal. Conversely, if the results of the comparison by the motion detection / judgment unit 90 do not match, the motion detection / judgment unit 90 outputs an instruction to the motion detector 61b to perform motion detection, and calculates the motion vector by the motion detector 61b. Is performed. For the shape signal, the subsequent processing is the same as in the thirteenth embodiment, and the encoded signal
And 68b are obtained.

As described above, the image coding apparatus according to the sixteenth embodiment has a configuration in which the motion detection determination unit 90 is added to the image coding apparatus according to the thirteenth embodiment.
It is determined whether motion compensation of the input shape signal can be performed using the motion vector of the input pixel value signal, and when it is determined that motion compensation is possible, the calculation is performed by not performing motion detection on the input shape signal. By omitting it, the processing load can be reduced. If it is determined that it is impossible,
As in the thirteenth embodiment, the motion detection is performed on the shape signal, so that the coding efficiency and the image quality of the coded signal are not affected. In the sixteenth embodiment, when the shape signal subjected to the motion compensation and the input shape signal match, the motion detection for the shape signal is not performed.
If a slight decrease in coding efficiency due to an increase in the motion compensation error can be tolerated, it is possible to make a setting so that the motion detection is not performed even when the error due to the motion compensation is equal to or less than a predetermined value in the determination. The burden can be reduced.

Embodiment 17 FIG. Embodiment 17 of the present invention
The image encoding apparatus according to the present invention uses an image signal composed of a shape signal and a pixel value signal as an input signal and encodes the input signal with reference to a reference image, as in the thirteenth to sixteenth embodiments. is there. FIG. 21 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 17 of the present invention. In the figure, reference numeral 93 denotes a switching determiner, which inputs a pixel value signal and a motion vector of a shape signal, and performs motion compensation of the shape signal using the motion vector of the pixel value signal as in the sixteenth embodiment. Is determined, and an instruction is given to the switch 94 in accordance with the determination. The switch 94 switches between the output to the difference value calculator 70 as the motion vector of the pixel value signal and the motion vector of the shape signal in response to the instruction of the switch determiner 93. The motion vector memory 95 temporarily stores the motion vector output from the switch 94 in order to delay and input the delayed motion vector to the difference detector 70. Other symbols are the same as those in FIG. 19, and the description is the same as that in the fifteenth embodiment. The operation of the apparatus of the seventeenth embodiment is also the same as that of the fifteenth embodiment except that the difference motion vector acquired by the difference value calculator 70 is different based on the determination of the switching determiner 93. Only the operation will be described.

The switching determiner 93 inputs and compares the motion signal of the motion vector of the pixel value signal and the motion vector of the shape signal with respect to the immediately preceding input signal, thereby performing the immediately preceding encoding. Input signal
It is checked whether the motion vector of the shape signal has been encoded. That is, by processing the signal encoded immediately before, whether the encoded signal of the differential motion vector obtained from the encoder 67b is a differential vector between the motion vector of the pixel value signal and the motion vector of the shape signal, It is checked whether the motion vector of the shape signal is a difference vector. Then, if the difference vector between the motion vectors of the shape signals has been encoded, an instruction is sent to the switch 94 to cause the delay memory 95 to input the motion vector detected from the shape signal. So in this case,
The difference value calculator 70 obtains a difference vector between the motion vector of the shape signal immediately before obtained from the delay memory 95 and the motion vector detected from the input shape signal, and the encoder 67 b Encode the vector. On the other hand, when the difference vector between the motion vector of the pixel value signal and the motion vector of the shape signal has been encoded in the immediately preceding input signal, by sending an instruction to the switch 94, the same as in the fifteenth embodiment is performed. , The difference vector between the motion vectors of the two signals is encoded.

As described above, in the image coding apparatus according to the seventeenth embodiment, based on the configuration of the image coding apparatus according to the fifteenth embodiment, the switching determination unit 93 and the switching unit 94
And a delay memory 95, when a motion vector of the shape signal has been coded immediately before, a difference vector between the motion vector and the detected motion vector is obtained to code the motion vector. Therefore, the coding efficiency can be improved by using the difference between the motion vectors of the highly correlated shape signals. In the seventeenth embodiment, the determination and the encoding of the difference vector are performed for the motion vector of the shape signal, but the determination and the encoding of the difference vector are performed for the motion vector of the pixel value signal. It is also possible to improve the coding efficiency.

Embodiment 18 FIG. Embodiment 18 of the present invention
The image encoding apparatus according to the present invention encodes an image signal composed of at least one of shape information, transparency information, and pixel value information as an input image signal in a mode suitable for each signal. FIG. 22 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 18 of the present invention. In FIG. 1, reference numeral 101 denotes an input image signal, and at least one of shape information and transparency information;
And pixel value information. Reference numeral 102 denotes a blocker, which blocks the input image signal 101 to form a block shape signal 103 and a block transmittance signal 1
05, and a pixel value signal 107 which is divided into blocks. 110 is a shape coding mode determiner, 114 is a transmittance coding mode determiner, and 116 is a pixel value coding mode determiner, which are a shape signal 103 and a transmittance signal 10 respectively.
5, and an appropriate encoding mode is determined for the pixel value signal 107, and the shape encoding mode 111, the transparency encoding mode 115, and the pixel value encoding mode 119 are output. 112 is a shape encoder, 116 is a transparency encoder,
Reference numeral 120 denotes a pixel value encoder, which encodes each signal according to the determination of the mode determiner, and outputs a shape encoded signal 113, a transmittance encoded signal 117, and a pixel value encoded signal 121. 122 is a mode encoder,
The encoding modes 111, 115, and 119 are collectively encoded, and a mode encoded signal 123 is output.

The eighteenth embodiment configured as described above
The operation of the image coding apparatus according to the first embodiment will be described. First, an input image signal 101 including shape information, transparency information, and pixel value information is input to the image encoding device according to the eighteenth embodiment. Here, the transparency information and the shape information will be described with reference to FIG. 53 used for describing the related art. The transparency information indicates the ratio of each pixel to be combined when combining the image shown in FIG. 53 (a) with another image. ) Is multi-valued information. The shape information is binary information shown in FIG. 53 (c).
And is information indicating that the object is “present / not present”. When there are only two types of transparency information, that is, completely transparent and completely opaque, the above can be expressed only by the shape information, and the transparency information is unnecessary. Therefore, in this case, only the shape information and the pixel value information need to be encoded or decoded. Blocking device 10
2 integrates a plurality of pixels into blocks based on the correspondence between the pixel values of the shape information / transparency information and the pixel value information with respect to the input image signal 101, and forms the blocked shape signal 103; It outputs a blocked transmittance signal 105 and a blocked pixel value signal 107. The shape signal 103 is transmitted to the shape encoding mode determiner 110 and the shape encoder 112, the transparency signal 105 is transmitted to the transparency coding mode determiner 114 and the transparency encoder 116, and
The pixel value signal 107 is supplied to a pixel value encoding mode determiner 118
And the pixel value encoder 120.

The shape coding mode determiner 110, the transmittance coding mode determiner 114, and the pixel value coding mode determiner 118 convert the input shape signal 103, transmittance signal 105, and pixel value signal 107, respectively. On the other hand, an appropriate encoding mode is determined, and the shape encoding mode 111, the transparency encoding mode 115, and the pixel value encoding mode 11 are determined.
9 is output. Each encoding mode is output to each encoder and also to the mode encoder 122.
The shape encoder 112, the transparency encoder 116, and the pixel value encoder 120 output the respective input signals corresponding to the respective input encoding modes, and output the shape encoded signal 113, It outputs a degree encoded signal 117 and a pixel value encoded signal 121. On the other hand, mode encoder 1
Reference numeral 22 collectively encodes the input encoding modes and outputs a mode encoded signal 123. The shape encoded signal 113, the transparency encoded signal 117, the pixel value encoded signal 121, and the mode encoded signal 123 are encoded outputs of the image encoding device according to the eighteenth embodiment.

As described above, in the image coding apparatus according to the eighteenth embodiment, a blocker 101 that blocks an input image signal and separates and outputs the shape signal, the transmittance signal, and the pixel value signal, Coding mode determiners 110, 114, and 1 for determining a coding mode suitable for each signal
18 and encoders 112, 116, and 120 for encoding each signal in accordance with the encoding mode, and a mode encoder 122 for encoding the encoding modes collectively. Encoding is performed in a mode suitable for each signal, and information on the selected mode can be encoded collectively. Shape information, transparency information, and pixel value information often have a correlation with each other,
Therefore, the same encoding mode is easily selected. Therefore, by performing variable-length coding in which codes having the same mode have a shorter code length, an effect is obtained in which the number of bits of a mode-coded signal can be reduced.

Embodiment 19 FIG. Embodiment 19 of the Invention
As in the eighteenth embodiment, the image encoding apparatus according to the present invention uses an image signal composed of at least one of shape information, transparency information, and pixel value information as an input image signal, Are encoded. FIG. 23 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 19 of the present invention. In the figure, a shape encoding mode determiner 110 determines an encoding mode adapted to the shape signal 103, and outputs the result of the determination to the shape encoder 112 and the mode encoder 122 as an encoding mode. , The transparency encoding mode determiner 130,
And the pixel value encoding mode determiner 132. Then, the transparency coding mode determiner 130 makes a determination with reference to the input shape coding mode 111, and uses the determination result as a coding mode for the transmittance encoder 116 and the mode encoder 122. In addition to the output, it is also output to the pixel value encoding mode determiner 132. The pixel value encoding mode determiner 132 determines the input shape encoding mode 11
1 and the transparency encoding mode 115 to make the determination.

The operation of the image coding apparatus according to the nineteenth embodiment is the same as that of the eighteenth embodiment except for the determination by the mode determiners described above.
3. Transparency encoded signal 117, pixel value encoded signal 12
1 and the mode coded signal 123 are output. As described above, in the image coding apparatus according to Embodiment 19, with reference to the shape coding mode, the transparency coding mode determiner 130 that determines the coding mode of the transparency signal, the shape coding mode, And the pixel value encoding mode determiner 132 that determines the encoding mode of the pixel value signal with reference to both the transmission encoding mode and the transparency encoding mode. Therefore, in mode encoder 122 that assigns short codes when modes match, the efficiency of variable-length encoding can be further improved as compared with the eighteenth embodiment, and the number of bits of the mode-encoded signal can be reduced. The effect is obtained.

Embodiment 20 FIG. Embodiment 20 of the present invention
The image coding apparatus according to the third embodiment improves the coding efficiency of the mode coded signal as in the nineteenth embodiment. FIG. 24 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 20 of the present invention. In the figure, a pixel value coding mode determiner 118 determines a coding mode adapted to the pixel value signal 107, and uses the determination result as a coding mode as a pixel value encoder 120 and a mode encoder 1
22 and a transparency encoding mode decision unit 1
36 and the shape encoding mode determiner 138. Then, the transparency coding mode determiner 136 makes a determination with reference to the input pixel value coding mode 119, and uses the determination result as a coding mode as the transparency encoder 116 and the mode encoder 122. , And also to the shape encoding mode determiner 138. The shape coding mode determiner 138 makes a determination with reference to the input pixel value coding mode 119 and the transparency coding mode 115.

The operation of the image coding apparatus according to the twentieth embodiment is the same as that of the eighteenth embodiment except for the determination by the mode determiners described above.
3. Transparency encoded signal 117, pixel value encoded signal 12
1 and the mode coded signal 123 are output. As described above, in the image coding apparatus according to Embodiment 20, the transparency coding mode determiner 136 that determines the coding mode of the transparency signal with reference to the pixel value coding mode, and the pixel coding mode , And the shape coding mode determiner 138 that determines the coding mode of the shape signal with reference to both the transmission coding mode and the transmission coding mode, so that the selected mode is likely to be the same. Therefore, in the mode encoder 122 that allocates a short code when the modes match,
The effect that the efficiency of variable-length coding is further improved as compared with the eighteenth embodiment, and the number of bits of the mode-coded signal can be reduced.

Embodiment 21 FIG. Embodiment 21 of the present invention
The image decoding apparatus according to the present invention performs appropriate decoding on the encoded signal efficiently encoded by the image encoding apparatus according to the eighteenth embodiment. FIG. 25 is a block diagram showing a configuration of an image decoding device according to Embodiment 21 of the present invention. In the figure, input signals 113, 11
Reference numerals 7, 119, and 123 denote shape encoded signals 113 output by the image encoding apparatus according to Embodiment 18;
These are a transparency coded signal 117, a pixel value coded signal 119, and a mode coded signal 123. A mode decoder 150 decodes the mode coded signal 123 and outputs a shape coding mode 151, a transparency coding mode 153, and a pixel value coding mode 155. 156, a shape decoder; 158, a transparency decoder; 160, a pixel value decoder;
3, the transparency encoded signal 117, and the pixel value encoded signal 1
19, and outputs a shape decoded signal 157, a transmittance decoded signal 159, and a pixel value decoded signal 161.
Numeral 162 denotes an inverse blocker which outputs the shape decoded signal 15
7, the decoded transparency signal 159, and the decoded pixel value signal 1
61, these are integrated, and a decoded image signal 163 is output.

The twenty-first embodiment configured as described above
The operation of the image decoding apparatus according to the above will be described. A shape coded signal 113, a transparency coded signal 117, a pixel value coded signal 119, and a mode coded signal 123 are input to the image decoding device according to the twenty-first embodiment, and the shape decoder 156, It is input to the transparency decoder 158, the pixel value decoder 160, and the mode decoder 150. The mode decoder 150 outputs the mode encoded signal 1
23, and the shape encoding mode 151, the transparency encoding mode 153, and the pixel value encoding mode 155 are
Each of the shape decoder 156, the transparency decoder 158,
And to the pixel value decoder 160. Shape decoder 1
56, transparency decoder 158, and pixel value decoder 16
0 indicates that the input coded signal is decoded and the shape decoded signal 15
7, the decoded transparency signal 159, and the decoded pixel value signal 1
61 is output to the deblocker 162. The deblocker 162 integrates the input decoded signals and outputs a decoded image signal 163.

As described above, in the image decoding apparatus according to the twenty-first embodiment, the mode decoder 150, the shape decoder 156, the transparency decoder 158, and the pixel value decoder 16
By providing 0 and the deblocker 162, the coded signal obtained by the image coding apparatus according to the eighteenth embodiment is appropriately decoded and integrated to obtain a decoded image signal 163. It becomes possible. In addition, Embodiment 2
In the first image decoding apparatus, the coded signal obtained by the image coding apparatus according to the eighteenth embodiment is decoded, but the code obtained by the image coding apparatus according to the nineteenth and twentieth embodiments is decoded. Similarly, it is possible to perform appropriate decoding on the coded signal.

Embodiment 22 FIG. Twenty-second embodiment of the present invention
Is an apparatus for performing coding by switching between intra-screen / inter-screen coding according to an input signal. FIG. 26 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 22 of the present invention. In the figure, 178
Is an intra-screen / inter-screen encoding determiner for pixel value encoding,
With respect to the encoding mode of the pixel value signal, a determination is made within the screen or between the screens, and the encoding mode 119 of the pixel value signal is output. Reference numeral 138 denotes a shape encoding mode determiner, which corresponds to the shape encoding mode determiner according to the twentieth embodiment shown in 138 of FIG. Switches 170 and 176 are switched according to the output of the determiner 178, and determine the encoding mode of the shape signal. Reference numeral 172 denotes a shape coding intra-screen / inter-screen coding determiner which determines a coding mode of a shape signal within a screen or between screens, and determines a coding mode 17 of a shape signal based on a result of the determination.
3 is output. Other symbols are the same as in FIG. 22, and the description is the same as in the eighteenth embodiment.

The twenty-second embodiment constructed as described above
The operation of the image coding apparatus according to the first embodiment will be described. First, when the input image signal 101 is input to the image encoding apparatus according to Embodiment 22, the blocker 102 performs blocking and signal separation similarly to Embodiment 18.
A pixel value signal and a shape signal are output. When the separated pixel value signal 107 is input to the pixel value encoding intra / inter-screen encoding determiner 178, the determiner 178 outputs the pixel value signal 10
7 is to be encoded by intra-screen encoding or inter-screen encoding, and the result of the determination is determined by pixel value encoding indicating either “intra-screen” or “inter-screen”. As the mode 119, the pixel value encoder 120, the mode encoder 122, and the shape encoding mode determiner 138
Output to

In the shape coding mode determination unit 138, the switches 170 and 176 are switched according to the pixel value coding mode 119. When the pixel value encoding mode indicates “in screen”, the input is not input to the determiner 178. When the pixel value encoding mode indicates “between screens”, the input is input to the determiner 178. Accordingly, when the pixel value encoding mode 119 indicates the intra-screen encoding, the shape determination mode 111 indicating the intra-screen encoding is output from the determiner 138.

On the other hand, when the pixel value encoding mode 119 indicates inter-picture encoding, it is determined whether the shape signal should be encoded by intra-picture encoding or inter-picture encoding in response to the shape signal 105. Intra / inter-screen coding determiner 172
Is determined, and the result of the determination is output as the shape encoding mode 111. In any case, shape encoding mode 1
11 is a shape encoder 112 and a mode encoder 122
Is output to The operations of the pixel value encoder 120, the shape encoder 112, and the mode encoder 122 are the same as those in the eighteenth embodiment, and each encoded signal is output.

From the above operation, in the image coding apparatus according to the twenty-second embodiment, when the pixel value signal is intra-coded, the shape signal is always intra-coded. . In general, when the pixel values do not match, the shapes do not match. Therefore, when the pixel value signal is to be coded in the screen, that is, when the correlation is small in time, as in the twenty-second embodiment, Even if the number of coding modes for shape signal coding is limited, the coding efficiency of shape signal coding hardly deteriorates. Further, even when the shape signal at the time of synthesis is constant, such as an inlaid image (synthesized image), the pixel value to be synthesized may change. In such a case, inter-picture coding is performed by the pixel value signal. Even if it is selected, the inter-picture coding is not always appropriate for the shape signal. In the apparatus according to the twenty-second embodiment, when the inter-picture coding is selected for the pixel value signal, the shape signal
Since it is determined which is between the screens, the coding of the shape signal can also select the coding mode of intra-screen coding, and inappropriate inter-screen coding in the coding of the shape signal is performed. It is possible to prevent the coding efficiency from being greatly degraded due to this.

When at least one of the shape signal and the pixel value signal is inter-coded, much additional information necessary for motion compensation performed in inter-picture coding is required. In the image coding apparatus according to the twenty-second embodiment, since only the shape signal is not inter-coded, the number of bits can be reduced when intra-picture coding is selected for the pixel value signal. In general, the number of bits of the additional information is smaller than the number of bits when the pixel value signal is intra-coded, but is a bit number that cannot be ignored when compared with the number of bits required for intra-coding of the shape signal. Therefore, the effect is great. As described above, according to the image coding apparatus of Embodiment 22, the intra-screen / inter-screen coding determiner 178 for pixel value coding and the intra-screen / inter-screen coding determiner 172 for shape coding are used. With the inclusion of the shape coding mode determination unit 138 to include, when the coding mode of the pixel value signal is the intra-screen coding, the coding mode of the shape signal is set to the intra-screen coding, When the coding mode is inter-picture coding, the coding mode of the shape signal is determined by selecting the coding mode. Therefore, the correlation between the coding mode 119 of the pixel value signal and the coding mode 111 of the shape signal is increased. By reducing the number of bits of the mode-coded signal and suppressing the selection of performing inter-screen coding, the number of bits of additional information for motion compensation can be reduced.

Embodiment 23 FIG. Embodiment 23 of the present invention
Is an image coding apparatus for performing coding by switching the number of motion vectors in coding in accordance with an input signal. FIG. 27 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 23 of the present invention. In the figure, reference numeral 188 denotes a motion vector number judging unit for pixel value encoding, which judges how many motion vectors are used in a pixel value signal encoding mode, and determines a pixel value signal encoding mode. 119 is output. Reference numeral 138 denotes a shape encoding mode determiner, which corresponds to the shape encoding mode determiner according to the twentieth embodiment shown in 138 of FIG. Switches 180 and 186 are switched according to the output of the determiner 188 and determine the encoding mode of the shape signal. Reference numeral 182 denotes a shape encoding motion vector number determiner which determines the number of motion vectors for the shape signal encoding mode, and outputs a shape signal encoding mode 183 according to the determination result. . Other symbols are the same as in FIG. 22, and the description is the same as in the eighteenth embodiment.

The twenty-third embodiment constructed as described above
The operation of the image coding apparatus according to the first embodiment will be described. First, when the input image signal 101 is input to the image coding apparatus according to Embodiment 23, the blocker 102 performs blocking and signal separation similarly to Embodiment 18.
A pixel value signal and a shape signal are output. The separated pixel value signal 107 is used as a motion vector number determiner 188 for pixel value encoding.
Is input to the pixel value signal 107, the determiner 188 determines the number of motion vectors to be coded, and the result of the determination is set to the pixel value Encoder 120 and mode encoder 12
2 and output to the shape encoding mode determiner 138.

FIG. 28 is a diagram for explaining the number of motion vectors. The motion is complicated near the contour of the object, and it is difficult to sufficiently reduce the motion compensation error by using one motion vector (MV) for each block.
In such a case, it is desirable to divide the block and assign a motion vector to each divided block. Thus, the coding efficiency is improved by adaptively changing the number of motion vectors according to the properties of the image. It is known to Therefore, in the image coding apparatus according to Embodiment 23,
As shown, one motion vector (MV
1) adaptively determine whether motion compensation is to be performed by using, or to perform motion compensation using four motion vectors (MV1, MV2, MV3, MV4), each of which is divided into four blocks, one for each divided block. Shall be switched. Therefore, the determiner 188 determines whether the number of motion vectors is one or four, and outputs “1” or “4” as the encoding mode of the pixel value signal.

In the shape coding mode determination unit 138, the switches 180 and 186 are switched according to the pixel value coding mode 119. When the pixel value encoding mode indicates “1”, the pixel value encoding mode is not input to the determiner 182,
When “4” is indicated, switching is performed so as to be input to the determiner 182. Therefore, when the pixel value encoding mode 119 is “1”, the shape determination mode 111 of “1” which is the minimum number of motion vectors is output from the determiner 138.

On the other hand, when the pixel value encoding mode 119 is "4"
When the motion vector number is determined, the motion vector number determiner 182 determines whether the number of motion vectors is one or four in accordance with the shape signal 105, and the determination result is output as the shape encoding mode 111. Is done. In any case, the shape encoding mode 111 is output to the shape encoder 112 and the mode encoder 122. And the pixel value encoder 1
20, shape encoder 112, and mode encoder 122
Is the same as that of the eighteenth embodiment, and each encoded signal is output.

With the above operation, in the image coding apparatus according to the twenty-third embodiment, when the pixel value signal is coded using the minimum number of motion vectors, the shape signal always has the minimum number. The encoding is performed using the motion vector. Increasing the number of motion vectors increases the amount of additional information required to encode the motion vectors, which is not preferable. In such a case, the burden is reduced by suppressing the number of motion vectors for shape signal encoding. Is prevented from increasing.

As described above, according to the image coding apparatus of the twenty-third embodiment, the motion vector number judging device 188 for pixel value encoding and the motion vector number judging device 182 for shape encoding are included. By providing the mode determiner 138, when the coding mode of the pixel value signal uses the minimum number of motion vectors, the coding mode of the shape signal is set to the minimum number, and the coding mode of the pixel value signal is many. When the vector of the pixel value signal is used, the encoding mode of the pixel value signal is determined by selecting the encoding mode of the shape signal.
19 and the coding mode 111 of the shape signal can be enhanced to reduce the number of bits of the mode coded signal, and by suppressing the selection of increasing the number of motion vectors, the additional information can be reduced. The increase in the number of bits for the increase can also be suppressed.

Embodiment 24 FIG. Embodiment 24 of the present invention
Is an apparatus for performing coding by switching between change / non-change of a quantization step in accordance with an input signal. FIG. 29 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 24 of the present invention. In the figure, reference numeral 198 denotes a quantization step change / non-change determination unit for pixel value coding, which determines whether or not to change the quantization step for the pixel value signal coding mode. , A pixel value signal encoding mode 119 is output. Reference numeral 138 denotes a shape encoding mode determiner, which corresponds to the shape encoding mode determiner according to the twentieth embodiment shown in 138 of FIG. Switches 190 and 196 are switched according to the output of the determiner 198 to determine the encoding mode of the shape signal. Reference numeral 192 denotes a shape coding quantization step change / non-change determination unit that determines whether or not to change the quantization step for the shape signal coding mode, and determines the shape based on the result of the determination. The signal encoding mode 193 is output. Other symbols are the same as in FIG. 22, and the description is the same as in the eighteenth embodiment.

The twenty-fourth embodiment configured as described above
The operation of the image coding apparatus according to the first embodiment will be described. First, when the input image signal 101 is input to the image coding apparatus according to Embodiment 24, the blocker 102 performs blocking and signal separation similarly to Embodiment 18.
A pixel value signal and a shape signal are output. When the separated pixel value signal 107 is input to the quantization step change / non-change determination unit 198 for pixel value encoding, the determination unit 198 changes the quantization step for the pixel value signal 107, Or not to perform, and the result of the determination, "change",
Alternatively, as the pixel value encoding mode 119 indicating either “unchanged”, the pixel value is output to the pixel value encoder 120, the mode encoder 122, and the shape encoding mode determiner 138.

In the shape encoding mode determination unit 138, the switches 190 and 196 are switched according to the pixel value encoding mode 119. When the pixel value encoding mode indicates “unchanged”, the input is switched to the input to the determiner 192, and when the pixel value encoding mode indicates “changed”, the input is input to the determiner 192. Therefore, pixel value encoding mode 1
When 19 indicates that the quantization step is not changed, the determination unit 138 outputs the shape determination mode 11 indicating “unchanged”.
1 will be output.

On the other hand, if the pixel value encoding mode 119 indicates that the quantization step is to be changed, the shape signal 105
In response to the above, the determiner 192 determines whether or not to change the quantization step, and the result of the determination is output as the shape encoding mode 111. In either case, the shape encoding mode 111 is
And the mode encoder 122. The operations of the pixel value encoder 120, the shape encoder 112, and the mode encoder 122 are the same as those in Embodiment 18,
Each encoded signal is output.

Since the value of the quantization step is directly related to the degree of compression, that is, the transmission rate of the coded signal, generally, the transmission rate or the recording rate of the coded signal obtained by coding an image is set to be substantially constant. If the transmission rate is higher than a predetermined value, control is performed to make the quantization step coarser, whereas if the transmission rate is lower than the predetermined value, the quantization step is made denser. Further, since the value of the quantization step directly affects the image quality of the coded signal, if the image is such that the pixel value changes sharply, it is difficult to visually detect the image quality deterioration in the amplitude direction. Therefore, it is possible to increase the quantization step and increase the compression ratio. Changing the quantization step according to such a change in the pixel value is also generally performed.

When such control for changing the quantization step is performed, additional information indicating that the quantization step has changed is added for each block, and is encoded together with the image data. However, it is often the case that the quantization step should be changed simultaneously for the pixel value signal and the shape signal, and if the quantization step for the pixel value signal is not changed, the quantization step for the shape signal is not changed. Even if such restrictions are applied, the image quality degradation due to such restrictions is slight, while additional information indicating a change in the quantization step can be greatly reduced.
As described above, according to the image coding apparatus of the twenty-fourth embodiment, the quantization step change / non-change determining unit 198 for pixel value coding and the quantization step change / non-change determining unit 192 for shape coding are different. With the inclusion of the shape coding mode determination unit 138 to include, when the coding mode of the pixel value signal is “quantization step non-change”, the coding mode of the shape signal is set to “quantization step non-change”. If the encoding mode of the pixel value signal is “quantization step change”, the encoding mode of the shape signal is determined and selected, so that the encoding mode 119 of the pixel value signal and the encoding of the shape signal are performed. It is possible to reduce the number of bits of the mode coded signal by increasing the correlation with the mode 111, and to suppress the selection that the quantization step is changed. That additional information increased suppression, it is also possible to reduce the number of bits.

The image coding apparatuses according to the twenty-second to twenty-fourth embodiments have a configuration similar to that of the twentieth embodiment shown in FIG. 24. However, the nineteenth embodiment shown in FIG.
It is also possible to adopt a configuration that conforms to the above, and it is also possible to increase the correlation between the encoding modes and reduce the number of bits by suppressing an increase in additional information. Also,
The configuration according to the eighteenth embodiment shown in FIG. 20 can be adopted, and the number of bits can be reduced while realizing encoding suitable for each signal. Embodiment 22 to
The coded signal obtained by the 24 image coding apparatus can be appropriately decoded by the image decoding apparatus according to Embodiment 21. In the eighteenth to twenty-first embodiments, it is assumed that an input image signal is composed of transmittance information and shape information in addition to pixel value information, and separation into a pixel value signal, a transmittance signal, and a shape signal is performed. Embodiment 2
In Nos. 2 to 24, the input image signal is separated into a pixel value signal and a shape signal. In this regard, even in Embodiments 22 to 24, if the transmittance information and the shape information match, it is possible to use only the shape information,
On the other hand, if they do not match, by setting the transparency information to a shape signal by setting the blocker, or by handling the transparency information which is a multi-value signal together with the pixel value information, the shape signal and the pixel Value signal.

Embodiment 25 FIG. Embodiment 25 of the present invention
Is an apparatus for inputting a two-dimensional image signal composed of a plurality of pixels and predicting and detecting a changed pixel. FIG. 30 is a block diagram showing a configuration of an image encoding device according to Embodiment 25 of the present invention. In the figure, 2
An input signal 01 is input to the image encoding apparatus as a binary image signal. Reference numeral 204c denotes a first changed pixel detector, which detects a pixel whose pixel value changes with respect to the input signal 201 and outputs the detected pixel as a first detected changed pixel 205c. Reference numerals 202a and 202b denote memories that temporarily store the input signal and delay the input signal,
Output as 3a and 203b. 204a and 2
Reference numeral 04b denotes a change pixel detector which detects a pixel whose pixel value changes with respect to the reference signals 203a and 203b, and detects second and third detected change pixels 203a and 203b.
Output as 3b. 206 is a change pixel predictor;
Based on the detected change pixels 203a and 203b, the first
, And outputs a predicted changed pixel 207. A subtracter 208 obtains a difference between the first changed pixel 205c and the predicted changed pixel 207, and converts the difference into a prediction error 20.
9 is output. An encoder 210 encodes the prediction error 209 and outputs an encoded signal 211.

The operation of the picture coding apparatus according to Embodiment 25 constructed as above will be described. FIG.
FIG. 1 is a diagram for explaining the principle of an encoding operation performed by the image encoding device according to the twenty-fifth embodiment. Here, for the sake of simplicity, the processing procedure will be described assuming that one pixel is sequentially processed. In FIG. 31, it is assumed that scanning is performed in the right direction from the upper left pixel, and encoding is performed in the lower right direction. The pixel value of each pixel has a binary value, and the presence or absence of a diagonal line indicates a true / false value (binary). Also, here
Encoding is completed for the first and second lines, and the third line (the line where the first changed pixel exists) is to be encoded. The changed pixel means the first pixel whose pixel value changes in the scanning as described above, and the changed pixel on the encoded line (scanning line) is the second changed pixel and the third changed pixel.
, And the first changed pixel on the uncoded scan line is the first changed pixel. Therefore, the first changed pixel is predicted from the second changed pixel and the third changed pixel, and the difference value (prediction error) between the predicted first changed pixel and the actual first changed pixel is calculated. If the calculation is performed, the prediction error has a distribution concentrated around 0, so that it is possible to efficiently perform encoding with a small number of bits using variable length encoding or the like.

In FIG. 30, first, an input signal 201 is input to the device. The image input signal 201 can be a normal color signal (pixel value signal) or a shape signal representing the shape of the object or the composition ratio of the object. The input signal 201 is input to the memories 202a and 202b and is temporarily stored. On the other hand, the input signal 201 is also input to the first changed pixel detector 204c,
c detects a pixel whose binary pixel value changes. This is the first change pixel in FIG. In FIG. 30, the first
Are input to the subtractor 208. On the other hand, the memory 202a delays the temporarily stored input signal 201 by two lines and outputs it as a reference signal 203a to the changed pixel detector 204a.
One second change pixel 205a is detected. Similarly, the memory 202b delays the temporarily stored input signal 201 by one line and changes the input signal 201 as the reference signal 203b.
The changed pixel detector 204b outputs the third changed pixel in FIG. In FIG. 30, changed pixels 205a and 205b are input to a changed pixel predictor 207.

An image generally has a correlation in the horizontal and vertical directions, and the first and second changed pixels are often arranged substantially on a straight line. The change pixel predictor 206 performs prediction from the input change pixel based on this, and outputs the obtained prediction change pixel 207 to the subtractor 208. The subtracter 208 obtains a difference between the input first changed pixel 205c and the predicted changed pixel 207, and outputs the difference as a prediction error 209 to the encoder 210.
The encoder 210 encodes the prediction error 209 and outputs an encoded signal 211. The predicted change pixel and the first detected
Since the prediction error, which is the difference value from the change pixel of, becomes a distribution concentrated near 0, if this is coded, using a variable-length coding that assigns a code with a small number of bits to a value close to 0, Efficient encoding can be performed with a small number of bits. As described above, in the image coding apparatus according to the twenty-fifth embodiment, the memories 202a and 202b and the changed pixel detector 204
a to c, a change pixel predictor 207, a subtractor 208,
The provision of the encoder 210 predicts a changed pixel of the input signal based on the changed pixel detected from the reference signal obtained by delaying the input signal, and encodes an error in the prediction. This makes it possible to improve the coding efficiency.

Embodiment 26 FIG. Embodiment 26 of the present invention
Is an apparatus for inputting a two-dimensional image signal composed of a plurality of pixels and predicting and detecting a changed pixel, and differs from the twenty-fifth embodiment in a method of acquiring a changed pixel used for prediction. is there. FIG. 32 shows Embodiment 2 of the present invention.
6 is a block diagram illustrating the configuration of an image encoding device according to No. 6. In the figure, reference numeral 201 denotes an input signal, which is input to the image encoding device as a binary image signal. Reference numeral 204 denotes a change pixel detector which detects a pixel whose pixel value changes with respect to the input signal 201 and outputs the detected pixel as a detected change pixel 205. 216a and 216b are memories,
Delaying is performed by temporarily storing the input changed pixel. The memory 216a delays the detection change pixel 205 to provide the reference change pixel 217a, and the memory 216b stores the reference change signal
17a is delayed and the reference change pixel 217b is output.
Reference numeral 206 denotes a change pixel predictor, which is a reference change pixel 217.
a) and predicts a changed pixel based on 217b and outputs a predicted changed pixel 207. Subtractor 208 and encoder 21
0 is the same as in the twenty-fifth embodiment.

The operation of the image coding apparatus according to the twenty-sixth embodiment configured as described above will be described. The input signal 201 similar to that of the twenty-fifth embodiment is
, The pixel whose binary pixel value changes is detected by the change pixel detector 204, and the detected change pixel 205 is output to the memory 216 a and the subtracter 208. Detected change pixel 2 input to memory 216a
05 is a reference change pixel 217a after a delay of one line.
Is output to the change pixel predictor 206 and the memory 216b. Reference change pixel 2 input to memory 216b
17a is a reference change pixel 2 after a delay of one line
17b is output to the change pixel predictor 206. By treating the reference changed pixels 217a and 217b as the second and third changed pixels in the twenty-fifth embodiment, the changed pixel predictor 206 can perform the same prediction as in the twenty-fifth embodiment. Pixel 207 is obtained.
Subsequent processing is the same as in the twenty-fifth embodiment. As described above, in the image coding apparatus according to the twenty-sixth embodiment, the memory 2
16a-b, a changed pixel detector 204, a changed pixel predictor 207, a subtractor 208, and an encoder 210 are provided so that a changed pixel detected from an input signal is referred to by delaying in a memory. By acquiring a changed pixel, predicting a changed pixel of the input signal based on the reference changed pixel, and coding an error related to the prediction, the coding efficiency is reduced in the same manner as in the twenty-fifth embodiment. Improvement can be achieved.

Embodiment 27 FIG. Embodiment 27 of the present invention
Is an apparatus for inputting a two-dimensional image signal composed of a plurality of pixels and predicting and detecting a changed pixel, and differs from the twenty-fifth embodiment in a method of acquiring a changed pixel used for prediction. is there. The image coding apparatus according to the twenty-seventh embodiment has the same configuration as the apparatus according to the twenty-fifth embodiment, and the description will be given with reference to FIG. In the image coding apparatus according to the twenty-fifth embodiment, as described with reference to FIG. 31, a changed pixel in one immediately preceding scan line and two scan lines immediately before a scan line to be encoded is used for prediction. But,
In the image coding apparatus according to the twenty-seventh embodiment, prediction is performed based on a changed pixel in a scanning line several lines before. FIG. 33 is a diagram for explaining the principle of the encoding operation performed by the image encoding device according to the twenty-seventh embodiment. With respect to the scanning line located at the bottom where encoding is performed, the second and third lines detected in the scanning lines 7 lines and 4 lines before
When the first changed pixel is predicted to be present on a straight line based on the changed pixel, the predicted changed pixel illustrated is obtained. Using a prediction error between the predicted changed pixel and a first changed pixel detected on the scanning line from the input signal,
By encoding the information “one pixel right of the predicted changed pixel”, the encoding efficiency can be improved as in the twenty-fifth embodiment.

The operation of the image coding apparatus of the twenty-seventh embodiment is the same as that of the twenty-fifth embodiment except that the delay time due to the temporary storage in the memories 202a and 202b is different. Further, with regard to the prediction by the changing pixel predictor 206, the changing pixel can be predicted by the following calculation.
The second changed pixel is the x-th pixel on the m-th line, the third changed pixel is the y-th pixel on the n-th line, and the predicted point of the first changed pixel is the z-th pixel on the k-th line. If they are arranged at the top, the relationship of xy: zy = mn: kn is established, so that zy = (xy) * (kn) / (mn). Therefore, z = y
Since-(xy) * (nk) / (mn), the first changed pixel is the y- (xy) * (nk) / (mn) pixel on the k-th line. As described above, in the image coding apparatus according to the twenty-seventh embodiment, with the same configuration as the image coding apparatus according to the twenty-fifth embodiment, the delay time using the memories 202a and 202b is changed by setting, and the same effect is obtained. Is obtained.

Embodiment 28 FIG. Embodiment 28 of the Invention
Is an apparatus for inputting a two-dimensional image signal composed of a plurality of pixels and predicting and detecting a changed pixel, and differs from the twenty-fifth embodiment in a method of acquiring a changed pixel used for prediction. is there. The image coding apparatus according to the twenty-eighth embodiment has the same configuration as that of the apparatus according to the twenty-fifth embodiment shown in FIG. 30, and includes a decoder for decoding the coded signal 211. And outputs the encoded and decoded signals to any of the memories. In the image coding apparatus according to the twenty-fifth embodiment, as described with reference to FIG. 31, a changed pixel in a scan line located on one line and two lines is used for prediction with respect to a scan line to be coded. However, in the image coding apparatus according to the twenty-eighth embodiment, a changed pixel in a scanning line at a lower position after coding and decoding is used for prediction. FIG. 34 is a diagram for describing the principle of the encoding operation performed by the image encoding device according to the twenty-eighth embodiment. Scanning line to be encoded (line where the first change pixel exists in the figure)
On the other hand, based on the second and third changed pixels detected on the scanning lines four lines above and three lines below, the first
Is predicted to be present on a straight line, the predicted changed pixel shown is obtained. By using the prediction error between the predicted changed pixel and the first changed pixel detected on the scanning line from the input signal, the information “two pixels to the right of the predicted changed pixel” is encoded, thereby implementing As in the case of the twenty-fifth and twenty-seventh aspects, the coding efficiency can be improved.

The operation of the image coding apparatus according to the twenty-eighth embodiment differs from that of the first embodiment in that the delay times due to the temporary storage in the memories 202a and 202b are different and the coded signal 211 output from the coder 210 is decoded. The present embodiment differs from the twenty-fifth embodiment only in that a corresponding changed pixel detector which is input to one of the memories and detects a changed pixel from the encoded and decoded signals is used. As described above, in the image coding apparatus according to the twenty-eighth embodiment, the same effect can be obtained by adding the path for decoding the coded signal to the reference image by adding the path to the image coding apparatus according to the twenty-fifth embodiment. .

Embodiment 29 FIG. Embodiment 29 of the Present Invention
Is an apparatus for inputting a two-dimensional image signal composed of a plurality of pixels and predicting and detecting a changed pixel, and delays and uses the detected changed pixel for prediction as in the twenty-sixth embodiment. Things. FIG. 35 is a block diagram showing a configuration of an image encoding device according to Embodiment 29 of the present invention. In the figure, reference numerals 216 and 220 denote memories for temporarily storing input changed pixels to delay them. The memory 216 delays the detection change pixel 205 and delays the change pixel 217, and the memory 220 stores the prediction error 2
09 is delayed and a delay prediction error 221 is output. 22
Reference numerals 2 and 224 denote adders. The adder 222 outputs the delay change pixel 217 and the delay prediction error 221 to the adder 224.
Performs an addition process of the prediction error 209 and the delay prediction error 221. Other symbols are the same as those in FIG. 32, and the description is the same as in the twenty-sixth embodiment.

The operation of the picture coding apparatus according to Embodiment 29 having the above structure will be described. FIG. 36 is a diagram for explaining the principle of the encoding operation performed by the image encoding device according to the twenty-ninth embodiment. Embodiment 26
Now, by delaying the detected first changed pixel, the second,
And a third changed pixel. On the other hand, in the image coding apparatus according to Embodiment 29, the second
The difference between the changed pixel and the third changed pixel is added to the third changed pixel and used as a predicted value of the first changed pixel. As shown in the figure, the difference between the second changed pixel and the third changed pixel is “two pixels to the left”, and the coding is performed by adding the “two pixels to the left” to the third changed pixel. Is obtained on the scanning line (the line where the first changed pixel exists in the figure) where the above-mentioned is performed. On the other hand, in the scan line to be encoded, a first changed pixel is detected, and "one pixel to the left" which is a difference between the detected first changed pixel and the predicted changed pixel is encoded. ,
The same effect as in the twenty-sixth embodiment can be realized. In FIG. 35, an input signal 201 is input to the image coding apparatus according to the twenty-ninth embodiment, a position where a binary pixel value changes is detected by a change pixel detector 204, and the first change pixel 205 is The data is output to the memory 216 and the subtractor 208. In the memory 216, the delay change pixel 217 delayed by one line is the third change pixel in FIG. The delay change pixel 217 is input to the adder 222,
In FIG. 36, the prediction change pixel 207 obtained by adding the delay prediction error 221 corresponding to the difference between the second and third change pixels and outputting the result is output to the subtractor 208.

The subtractor 208 outputs the difference between the detected changed pixel 204 and the predicted changed pixel 207 as a prediction error 209, and the prediction error 209 is coded by the encoder 210, and the coded signal 211 is output. You. Prediction error 2
09 is added to the delay prediction error 22 in the adder 224.
1 is added. The resulting delay prediction error 221
Is equivalent to the difference between the second and third changed pixels as described above, is delayed by being temporarily stored in the memory 220, and is used for the next encoding. That is,
In FIG. 36, in the next line (one line below), the above “two pixels to the left” which is in the delay error 221
"3 pixels to the left" obtained by adding the "1 pixel to the left", which is the prediction error 209, is used as the prediction value.

As described above, in the image coding apparatus according to the twenty-ninth embodiment, the memories 216 and 220, the changing pixel detector 204, the adders 216 and 220, and the subtractor 2
08 and the encoder 210, the delay pixel and the prediction error are subjected to delay processing and addition processing for the changed pixel detected from the input signal. It is possible to improve the efficiency. In each of the image coding apparatuses according to the twenty-fifth to twenty-ninth embodiments, input can be performed in block units, and processing can be performed in block units.

Embodiment 30 FIG. Embodiment 30 of the present invention
An image decoding device according to the present invention decodes an encoded signal output from the encoding device according to the twenty-fifth embodiment to obtain a two-dimensional image signal including a plurality of pixels. FIG. 37 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 30 of the present invention. In the figure, reference numeral 211 denotes an input signal, which is a coded signal of a prediction error output from the image coding apparatus according to Embodiment 25 (211 in FIG. 30).
A decoder 230 decodes the encoded signal 211 and outputs a decoded prediction error 231. An adder 232 performs an addition process on the decoded prediction error 231 and the predicted change pixel 207, and outputs the obtained decoded change pixel 233.
Reference numeral 234 denotes a pixel value generator, which sets a pixel located between the decoded changed pixel 233 and the previously decoded changed pixel as a predetermined pixel value, that is, a decoded image signal 235 is generated and output. Other symbols are the same as those in FIG. 30, and the description is the same as in the twenty-fifth embodiment.

The thirtieth embodiment constructed as described above
The operation of the image decoding apparatus according to
When the encoded signal 211 is input, the input signal 211 obtained by encoding the prediction error is decoded by the decoder 230, and the resulting decoded prediction error 231 is added to the adder 23.
2 is output. On the other hand, the image signal 2 decoded immediately before
35 is input to the memories 202a and 202b, and the prediction of the changed pixel is performed in the same manner as in the twenty-fifth embodiment.
7 is output. The adder 232 obtains the decoded changed pixel 233 by adding the input decoded prediction error 231 to the predicted changed pixel 207, and outputs this to the pixel value generator 234. The pixel value generator 234 converts the decoded image signal 235 to a pixel located between the decoded changed pixel 233 and the immediately preceding changed pixel as a predetermined pixel value, that is, a pixel value of a pixel that is not a changed pixel. Generate and output.

As described above, the image decoding apparatus according to the thirtieth embodiment includes the memories 202a-b, the changed pixel detectors 204a-b, the changed pixel predictor 207, and the decoder 2
30, the adder 232, and the pixel value generator 234, using the predicted change pixel and the decoded prediction error,
A decoded change pixel is obtained, and the decoded image signal 23 is
5, the coded signal according to the twenty-fifth embodiment can be appropriately decoded. In the thirtieth embodiment,
In the above, the coded signal is decoded by the image coding apparatus according to the twenty-fifth embodiment.
8 can also be decoded in the same manner.

Embodiment 31 FIG. Embodiment 31 of the present invention
The image decoding apparatus according to the present invention decodes an encoded signal output from the encoding apparatus according to the twenty-sixth embodiment to obtain a two-dimensional image signal including a plurality of pixels. FIG. 38 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 31 of the present invention. 37, a decoder 230, an adder 232, and a pixel value generator 234 are the same as those in FIG. 37, and the other components are the same as those in FIG. 32.
Is the same as

The thirty-first embodiment constructed as described above
The operation of the image decoding apparatus according to
When the encoded signal 211 is input, the input signal 211 obtained by encoding the prediction error is decoded by the decoder 230, and the resulting decoded prediction error 231 is added to the adder 23.
2 is output. On the other hand, the decoded changed pixel 233 decoded immediately before is input to the memory 216a, and is stored in the memory 216a.
Similarly to the above, the changed pixel is predicted, and the changed pixel predictor 206 outputs the predicted changed pixel 207 to the adder 232. Subsequent processing is the same as that of the thirtieth embodiment. As described above, the image decoding apparatus according to the thirty-first embodiment includes the memories 216 a and 216 b and the change pixel predictor 207.
, A decoder 230, an adder 232, and a pixel value generator 234, so that a decoded changed pixel is obtained using a predicted changed pixel and a decoded prediction error, and decoding is performed based on the decoded changed pixel. Since the image signal 235 is obtained, the encoded signal according to Embodiment 26 can be appropriately decoded.

Embodiment 32 FIG. Embodiment 32 of the present invention
An image decoding apparatus according to the present invention decodes an encoded signal output from the encoding apparatus according to the twenty-ninth embodiment to obtain a two-dimensional image signal including a plurality of pixels. FIG. 39 is a block diagram showing a configuration of an image encoding device according to Embodiment 32 of the present invention. 37, a decoder 230, an adder 232, and a pixel value generator 234 are the same as those in FIG. 37, and the other components are the same as those in FIG. 35.
Is the same as

The thirty-second embodiment constructed as described above
The operation of the image decoding apparatus according to
When the encoded signal 211 is input, the input signal 211 obtained by encoding the prediction error is decoded by the decoder 230, and the resulting decoded prediction error 231 is added to the adder 23.
2 is output. On the other hand, the decoded changed pixel 233 decoded immediately before is input to the memory 216, and the predicted changed pixel is output from the adder 222 to the adder 232, as in the twenty-ninth embodiment. Is done. Subsequent processing is the same as that of the thirtieth embodiment.

As described above, the image decoding apparatus according to the thirty-first embodiment includes the memories 216 and 220 and the adder 2
24, 222, and 232, a decoder 230, and a pixel value generator 234, a decoded changed pixel is obtained using a predicted changed pixel and a decoded prediction error, and based on the decoded changed pixel, Since the decoded image signal 235 is obtained, the embodiment 29
Can be appropriately decoded.
In the case where encoding is performed in block units in any of the image encoding apparatuses according to Embodiments 25 to 29, in the image decoding apparatus according to Embodiments 30 to 32,
Appropriate processing can be performed by inputting a coded signal in block units and performing processing in block units.

Embodiment 33 FIG. Embodiment 33 of the present invention
Is an apparatus for switching and outputting an encoding result of a prediction error or the number of pixels according to an image signal. FIG. 40 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 33 of the present invention. In the figure, reference numeral 240 denotes a subtractor, and the detected changed pixel 205
The difference 241 between b and 205c is obtained. Reference numeral 242 denotes an encoder, which encodes the difference 41 to generate an encoded signal 243.
Is output. Reference numeral 244 denotes a comparator for comparing the prediction error 209 with a predetermined value, and based on the result, the switch 24.
6 is controlled. Reference numeral 246 denotes a switch, which switches either one of the encoded signals 247 and 243 according to the thirty-third embodiment.
Is switched under control of the comparator 244. Other symbols are the same as those in FIG. 30, and the description is the same as in the twenty-fifth embodiment. The image encoding apparatus according to Embodiment 25 encodes a prediction error. However, since the encoding is performed on the assumption that the prediction error is small, the encoding efficiency is reduced when the prediction error increases. descend. In such a case, it is more efficient to encode the changed pixel itself (position) than to encode the prediction error. Therefore, the image encoding apparatus according to the thirty-third embodiment can encode the prediction error and encode the number of pixels indicating the position of the changed pixel. Also, by coding the changed pixels themselves (positions), the number of changed pixels changes, making prediction difficult or impossible, and in cases where prediction error coding becomes difficult or impossible. , Encoding can be performed.

The operation of the image coding apparatus according to the embodiment 33 configured as described above will be described. FIG.
FIG. 1 is a diagram for explaining the principle of an encoding operation performed by the image encoding device according to the thirty-third embodiment. The prediction of the first changed pixel from the second and third changed pixels is performed according to the second embodiment.
This is the same as the case of No. 5. In the thirty-third embodiment,
A prediction range corresponding to a predetermined value is set around the prediction change pixel. Then, encoding is switched based on whether or not the detected first changed pixel is in the prediction range. If the prediction pixel is in the prediction range, the prediction error is determined. Encode the changed pixels.

In the thirty-third embodiment, since the third changed pixel has already been coded and decoded, the third changed pixel must be coded and decoded in order to encode the first changed pixel. The difference in the scanning order from the first changed pixel, that is, the number of pixels existing between them, may be encoded. And
The pixels located in the above-mentioned prediction range among the pixels between them are coded by the prediction error and can be removed. Therefore, in order to encode the first changed pixel, it is sufficient to encode a pixel excluding the pixels in the prediction range from the difference between the changed pixels.

For example, the case where the changed pixel A and the changed pixel B in the drawing are outside the prediction range and these points are detected as the first changed pixel will be described. As in the description of the twenty-fifth embodiment, the scanning direction is from upper left to lower right, the first changed pixel is 3 * 12 + 6 = 42nd, the changed pixel A is 4 * 12 + 1 = 49th, and the changed pixel is B is 4 * 12 + 10
= 58th. Since there is no prediction range between the third changed pixel and the changed pixel A, the number of pixels 49-42 =
7 is encoded as information indicating the position of the changed pixel A, that is, A. On the other hand, in the case of the change pixel B, since the prediction range is included between the third change pixel and the change pixel B, five pixels existing in the prediction range are excluded and 58-4
2-5 = 11 is coded as information indicating the change pixel B, that is, information indicating the position of B. After the input signal 201 is input to the image encoding device of the thirty-third embodiment, the memory 20
Processing from the delay by 2a and 202b to the acquisition of the prediction error 209 by the subtractor 208 is performed in the same manner as in the twenty-fifth embodiment, and the encoder 210 obtains the encoded signal 247 of the prediction error 209. In the twenty-fifth embodiment, the coded signal is an output coded signal. In the thirty-third embodiment, the coded signal 247 is output to the switch 246. Further, the prediction error 209 is calculated by the encoder 242
And to the comparator 244.

On the other hand, the third changed pixel 205b detected by the changed pixel detector 204b and the changed pixel detector 204c
And the first change pixel 105c detected by the subtractor 24
0, and the number of pixels 241 existing between them is obtained as a difference between the two and output to the encoder 242.
The encoder 242 calculates the difference 241 and the prediction error 2
From 09, a pixel number coded signal 243 excluding the pixels existing in the prediction range is obtained, and this is output to the switch 246. The comparator 244 calculates, for the input prediction error,
It is determined whether or not the pixel is within the prediction range. If the pixel is within the prediction range, the switch 246 outputs the prediction error coded signal 247 as the output 211. Control is performed by the signal 245 so that the encoded signal 243 becomes the output 211. As described above, in the image coding apparatus according to the thirty-third embodiment, based on the image coding apparatus according to the twenty-fifth embodiment, the subtractor 240, the encoder 242 for the number of pixels, the comparator 244, and the switch 246 are provided. With the configuration including: a coding signal that outputs a coded signal of the prediction error when the prediction error is within a predetermined range, and a coded signal of the number of pixels when the prediction error is out of the range. Since it is a signal, if the prediction error is large, it is necessary to prevent a decrease in coding efficiency and perform appropriate coding even when the change pixel cannot be predicted due to a change in the number of changed pixels. Becomes possible.

Embodiment 34 FIG. Embodiment 34 of the Invention
The image decoding apparatus according to the present invention decodes an encoded signal output from the encoding apparatus according to the thirty-third embodiment to obtain a two-dimensional image signal including a plurality of pixels. FIG. 42 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 34 of the present invention. In the figure, reference numeral 250 denotes a mode decoder, which determines whether the input signal is a signal in which a prediction error is coded or a position (the number of pixels) of a changed pixel is a coded signal. The conversion mode 251 is output. Reference numeral 256 denotes a pixel number decoder which decodes the input signal 255 and outputs a decoded pixel number 257. Reference numeral 258 denotes an adder, which includes the predicted change pixel 205b and the decoded pixel number 257.
And outputs a decoded changed pixel 259. 2
52 and 260 are switches, and the mode decoder 25
Switching between an input signal and an output signal is performed in accordance with the encoding mode in which 0 is output. Other symbols are the same as those in FIG. 30, and the description is the same as in the twenty-fifth embodiment.

The thirty-fourth embodiment configured as described above
The operation of the image decoding apparatus according to
When the coded signal 211 is input, whether the prediction error is coded by the mode decoder 250 first,
It is determined whether the number of pixels is coded, and a coding mode of “prediction error” or “number of pixels” is output based on the result of the determination, and switching between the switches 252 and 260 is controlled. The operation in the case where the prediction error has been encoded is the same as that in the thirty-third embodiment. On the other hand, if the number of pixels has been encoded, by switching the switch 252, the input signal 211 is decoded by the decoder 256, and the number of pixels that is the difference between changed pixels is decoded.
The decoded pixel number 257 is output to the adder 258. In the adder 258, the decoded pixel number 257 is added to the predicted change pixel predicted based on the decoded image signal 235 obtained by decoding immediately before, and the decoded change pixel 259 is obtained. In any case, a decoded image signal 235 is output based on the decoded changed pixel 261 as in the thirtieth embodiment. As described above, in the image decoding apparatus according to the thirty-fourth embodiment, based on the image decoding apparatus according to the thirtieth embodiment, the mode decoder 250, the adder 258, the pixel number decoder 256, Switches 252 and 260
In this configuration, the switches 252 and 260 are switched according to the encoding mode obtained by the mode decoder 250, and appropriate decoding is selectively performed. The coded signal coded at 33 can be properly decoded.

Embodiment 35 FIG. Embodiment 35 of the Present Invention
The image encoding device and the image decoding device according to the above can change the setting of the prediction range in accordance with the image signal. An image coding apparatus and an image decoding apparatus according to the thirty-fifth embodiment have the same configurations as those of the thirty-third and thirty-fourth embodiments. FIG. 43 shows encoding according to the thirty-fifth embodiment.
Alternatively, it is a diagram for explaining the principle of the decoding operation. Figure
(a) shows a case where the input image is composed of 8 × 8 pixels, and FIG. (b) shows a case where the same example is subsampled by half to form a 4 × 4 pixel. . The number of pixels of the sub-sampled pixel is １ ／, while the distance between pixels is doubled. Therefore, in the case of a subsampled one, the same spatial position is searched by setting the prediction range to a range corresponding to half of the prediction range of the original one. For example, if the same range of ± 2 pixels as the original one on the left is used as the prediction range of the subsampled one on the right, it will exceed the number of pixels in one line, and in Embodiments 33 and 34, Mode switching is not performed properly. On the other hand, as shown in FIG.
In this case, the mode can be appropriately switched, so that the coding efficiency can be improved according to the embodiment.

As described above, in the image coding apparatus and the image decoding apparatus according to the thirty-fifth embodiment, the thirty-third embodiment
In the image encoding device according to the present invention, or the image decoding device according to the thirty-fourth embodiment, the size of the prediction range can be changed in accordance with the size of the image signal. Is performed appropriately, and the encoding efficiency can be improved.

Embodiment 36 FIG. Embodiment 36 of the present invention
Is an apparatus for encoding a shape signal representing the shape of an object, extracting a significant region from the image signal, and performing efficient encoding. FIG. 44 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 36 of the present invention. In the figure, reference numeral 401 denotes a two-dimensional shape signal which is an input signal. Reference numeral 402 denotes a significant region extractor, which extracts a significant region from the input shape signal 401 and outputs a significant region signal 403. Reference numeral 404 denotes a blocking unit which blocks the input shape signal 401 and outputs a blocked shape signal 405. A switch 408 performs switching in accordance with the significant area signal 403. A block size changer 412 changes the size of the block in response to the significant area signal 403 and outputs a changed blocked shape signal 413. 418,
And 414 are encoders, each of which has a significant area signal 4
03 and the block shape signal 413, and outputs coded signals 419 and 415.

The thirty-sixth embodiment constituted as described above
The operation of the image coding apparatus according to the first embodiment will be described. 2
The input signal 401 which is a dimensional shape signal is used in the third embodiment.
6 is input to the image coding apparatus of FIG.
Is input to the blocking unit 404. The significant area extractor 402 detects the range of the significant area, and switches the significant area signal 403 to the switch 408 and the block size changer 41.
2 and output to the encoder 418.

FIG. 45 is a diagram for explaining the principle of the encoding operation performed by the image encoding apparatus according to the thirty-sixth embodiment. The shaded portion is the pixel inside the object, that is, the pixel where a significant image signal exists, and the smallest rectangle including the shaded portion, that is, the rectangle shown by the thick line in FIG. The blocking unit 405 blocks the input shape signal and outputs the blocked shape signal 405 to the switch 408. Here, the switch 408 is
When the blocked shape signal 405 corresponds to the range of the significant area indicated by the significant area signal 403, the state becomes 0N.
That is, in the case of a region other than the significant region, the block shape signal is not coded.

When the switch is ON, the block shape signal 405 is input to the block size changer 412 and corresponds to the significant area signal 403 input to the block size changer 412. The size is changed to a block, and the changed shape signal 413 is output to an encoder 414, and is coded into a coded signal 415 of a shape signal. On the other hand, a significant area signal indicating the range of the significant area is also encoded by encoder 418, and encoded signal 419 is output. Thus, the third embodiment
6, the significant region detector 102
And the block size changer 412, the range of the significant region is detected, and the block size of the shape signal is changed so that the shape signal is encoded only inside the range of the significant region. Since the outside is not coded, the coding efficiency of the shape signal is improved.

Embodiment 37 FIG. Embodiment 37 of the present invention
The image decoding apparatus according to the third embodiment decodes an encoded signal output from the encoding apparatus according to the thirty-sixth embodiment to obtain a two-dimensional shape signal. FIG. 46 shows Embodiment 37 of the present invention.
FIG. 3 is a block diagram illustrating a configuration of an image decoding device according to the first embodiment.
In the figure, 419 and 415 are coded signals output from the image coding apparatus according to the thirty-sixth embodiment. 42
0 is a decoder for a significant area signal, and 422 is a decoder for a shape signal.
Is output. A block size changer 430 changes the size of the block in accordance with the decoded significant area signal 421 and outputs the changed decoded block shape signal 431. Reference numeral 426 denotes a switch, which is a significant area signal 421.
Switching is performed according to. An inverse blocker 432 integrates the blocked shape signal 427 and outputs a decoded shape signal 433.

This embodiment is constructed as described above.
The operation of the image decoding apparatus according to the above will be described. The encoded signals 419 and 415 are respectively output from the decoder 42
0 and 422 and decoded. Decoder 4
19 outputs the decoded significant area signal 421 to the block size changer 430 and the switch 426. On the other hand, the decoder 422 outputs the minimum blocked shape signal 423 which is the minimum block including the range of the significant region to the block size changer 430. Block size changer 430
Changes the block size to a predetermined size based on the input decoded significant area signal, and outputs the changed block shape signal 431 to the switch 426. The switch 426 is turned ON only when a signal including the range of the significant region indicated by the significant region signal 421 is input, and outputs a value indicating that the signal is outside the range of the significant region otherwise.
The deblocker 432 integrates the input blocked shape signal and a signal indicating the outside of the significant region, and outputs a two-dimensional shape signal as a decoded signal 433. As described above, in the image decoding apparatus according to Embodiment 37, the decoders 420 and 422 and the block size changer 43
0, the switch 426, and the deblocker 432, the range of the significant region is decoded, and the shape signal is decoded based on the range. The signal can be decoded correctly.

Embodiment 38 FIG. Embodiment 38 of the Present Invention
The image coding apparatus according to the above realizes good hierarchical coding by performing coding according to the prediction probability.
FIG. 47 is a block diagram showing a configuration of an image encoding device according to Embodiment 38 of the present invention. In FIG. 1, reference numeral 1 denotes an input image signal. Reference numeral 300 denotes a separator, which separates the input image signal 1 into two image signals 301a and 301b and outputs them. Encoders 302, 308a, and 308b encode an input signal and output an encoded signal. A decoder 330 decodes the encoded signal 303a and outputs a decoded image signal 331. A prediction probability calculator 304 predicts a pixel value of the image signal 301b based on the input image signal 331, calculates a prediction probability for the prediction, and calculates a probability value 30.
5 is output. Reference numeral 306 denotes a second separator, which separates the image signal 301b into image signals 307a and 307b in accordance with the input probability value 305 and outputs the separated image signal.

The thirty-eighth embodiment constructed as described above
The operation of the image coding apparatus according to the first embodiment will be described. The input signal 1 is input to the image coding apparatus according to the thirty-eighth embodiment. First, the image signals 301a and 301
01b. Here, the signal 301a is a signal selected with priority and is input to the encoder 302, and the other signal 301b is output to the second separator 306.
FIG. 48 is a diagram for describing the principle of the encoding operation performed by the image encoding device according to the thirty-eighth embodiment. Fig. 48 (a)
In FIG. 5, the solid-line circled pixels correspond to the image signal 301a, and the dashed-line circled pixels correspond to the image signal 301b.
FIG. 48 shows a model of a binary image signal, in which oblique lines indicate true values, and circles without oblique lines indicate false values. The encoder 302 encodes the high-priority image signal 301a, outputs the obtained encoded signal 303a as an encoded output, and also outputs the encoded signal 303a to the decoder 330.

[0207] The decoded signal decoded by the decoder 330 is input to the prediction probability calculator 304. The prediction probability calculator 304 predicts the pixel value of the low priority image signal based on the decoded high priority image signal, and calculates the prediction probability. In FIG. 48 (a), A is a false value in four adjacent directions, and B is a true value in four adjacent directions.
Is a true value in two adjacent directions and a false value in two adjacent directions. As a result, the probability that prediction is that A is a false value and B is a true value is high, but the probability that the prediction is correct for C is low. Therefore, if C is coded with priority over A and B shown in FIG. 48 (a), C is decoded as shown in FIG. 48 (b) and A and B are reproduced based on prediction. In this case, there is little deterioration in image quality, and desired gradation encoding can be performed.

Therefore, based on the probability value 305 output from the prediction probability calculator 304, the second separator 306 sets the image signal 301b having the higher probability value 305 as the image signal 307a and the other image signals as the image signal 307a. Signal 307
b, and each of the encoders 308a and 3
08b. Each encoder encodes the input image signal to generate encoded signals 303b and 303.
Output c. If the coded signals 303a to 303c output as described above are transmitted or recorded as having higher priority in this order, the coded signals 303a to c are decoded in order from the coded signal having higher priority in decoding. Even when the decoding process is terminated in the decoding process, a decoded image with little image quality degradation can be obtained. As described above, in the image coding apparatus according to the thirty-eighth embodiment, the separators 300 and 306, the encoders 302, 308a, and 308b, the decoder 330, and the prediction probability calculator 30
The provision of No. 4 makes it possible to implement hierarchical coding with little image quality degradation without additional information by preferentially coding pixels having a low prediction probability.

Embodiment 39 FIG. Embodiment 39 of the Present Invention
An image decoding apparatus according to the third embodiment decodes an encoded signal output from the encoding apparatus according to the thirty-eighth embodiment. FIG. 49 is a block diagram showing a configuration of an image decoding device according to Embodiment 39 of the present invention. In the figure, 303a
To c are coded signals output from the image coding apparatus according to Embodiment 38, and are decoded by the decoders 310, 316a, and 316b, and the decoded signals 311, 317
a and 317b. A predictor 320 predicts an image signal based on the image signal 311 and outputs a predicted image signal 321. A prediction probability calculator 312 calculates a prediction probability of the input predicted image signal 331 and outputs a probability value 313. A switch 322 switches according to the probability value 313.

The thirty-ninth embodiment having the structure described above
The operation of the image decoding apparatus according to the above will be described. The encoded signals 303a to 303c are supplied to decoders 310 and 31 respectively.
6a and 316b and decoded. Signal 3
03a is decoded, and the decoded image signal 311 becomes an output decoded signal, and is also input to the prediction probability calculator 312 and the predictor 320. The predictor 320 predicts the pixel value of the low priority image signal 321 from the decoded image signal 311. The prediction probability calculator 312 calculates the prediction probability of the predicted image signal 321 and calculates
It is determined whether decoding should be performed at 16a or 316b. Further, the prediction probability calculator 312 refers to the priority 309 input from the outside, and determines whether or not an encoded signal having a low priority is transmitted or recorded. If it is determined that the pixel value has not been transmitted or recorded, the control is performed such that the switch 322 is switched so that the pixel value of the pixel that has not been encoded is output as the predicted image signal 321 as the decoded signal 323. Further, for the decoded pixels, the image signals 311 and 317a,
Alternatively, any one of 317b and 317b is selected as a decoded signal 323 output from the device. As described above, in the image decoding apparatus according to the thirty-ninth embodiment, the decoder 31
0, 316a, and 316b and a predicted probability calculator 312
And the predictor 320, so that decoding corresponding to the prediction probability and the priority is performed, so that the coded signal coded by the image coding apparatus according to Embodiment 38 can be appropriately decoded. Can be.

Embodiment 40 FIG. Embodiment 40 of the present invention
The image encoding program recording medium and the image decoding program recording medium according to the present invention realize the image encoding device or the image decoding device according to any one of Embodiments 1 to 39 in a computer or the like. 50 shows a floppy (registered trademark) disk as an example of a recording medium for recording the program. FIG. 51 is a flowchart showing a processing procedure of the recorded image encoding program, and FIG. 52 is a flowchart showing a processing procedure of the image decoding program. FIG.

The image encoding program shown in FIG. 51 recorded on the floppy disk shown in FIG. 50 is executed by a personal computer, a workstation, or the like, thereby realizing the image encoding device according to the second embodiment. Similarly, the image decoding program shown in FIG. 52 recorded on the floppy disk shown in FIG. 50 is executed by a personal computer, a workstation, or the like, thereby realizing the image decoding apparatus according to the third embodiment. In this case, in this embodiment, a type in which selection by a switch is performed after the changing pixel decoding process described with reference to FIG.

As described above, the program recording medium according to the fortieth embodiment records an image encoding program or an image decoding program, so that the present invention can be applied to a general computer system such as a personal computer. It is possible to realize the image encoding device or the image decoding device. In the fortieth embodiment, a program for realizing the image encoding device of the second embodiment and the program for realizing the image decoding device of the third embodiment are recorded. It is feasible. Further, in the present embodiment 40, a floppy disk is shown as a recording medium, but an IC card, a CD-RO
The present invention can be similarly implemented as long as the medium can record a program, such as an M, an optical disk, and a cassette tape.

[0214]

As described above, according to the image encoding apparatus of the present invention (claim 1), a binary image signal is used as an input signal, and an image in which the pixel value of the input signal changes is encoded. An encoding device, comprising: a changed pixel detecting unit that detects a pixel whose pixel value changes and outputs the detected changed pixel as a detected changed pixel; and that changes the pixel value of the coded and decoded pixel. A prediction unit that predicts a change pixel of the input signal based on a pixel, and outputs the predicted pixel as a prediction pixel; a detection change pixel; and the prediction change pixel, and calculates a difference between the two. A difference value calculating unit that outputs a value D, a value within a range determined based on a preset allowable value, and the difference value D,
And D ′, which is the value that minimizes the code length when encoded.
And a decoding means for decoding a binary image signal from the corrected difference value D 'and the predicted changed pixel, and a rounding means for outputting the corrected difference value as a corrected difference value. Encoding means for encoding a ', a selected correction difference value that minimizes the code length of the error (difference value) for a prediction error equal to or less than the allowable value, and outputs the corrected difference value to obtain a code The number of bits required for the conversion can be reduced.

According to the image encoding apparatus of the present invention (claim 2), an image encoding apparatus which takes a binary image signal as an input signal and encodes a pixel whose pixel value of the input signal changes is provided. A changed pixel detecting unit that detects a pixel whose pixel value changes, and outputs the detected changed pixel as a detected changed pixel; and a coded and decoded pixel of the frame whose pixel value changes. A first prediction unit that predicts a changed pixel of the input signal based on the input signal and outputs the predicted pixel as a first predicted pixel; and calculates a difference between the detected changed pixel and the first predicted pixel. A first difference value calculating unit that outputs the calculated difference as a first difference value D, and a motion compensation based on a pixel whose pixel value changes among encoded and decoded pixels in the reference frame. And above A second predictor for predicting a changed pixel of the input signal and outputting the predicted pixel as a second predicted pixel; calculating a difference between the detected changed pixel and the second predicted pixel; A second difference value calculating unit that outputs the difference as a second difference value D ″, and a code when each of the first difference value D and the second difference value D ″ is coded Mode selection means for calculating the length, selecting the shorter code length by comparing the calculation results, and outputting either “first” or “second” as the encoding mode in response to the selection. , The selected first difference value D,
Or, since the encoding device includes encoding means for encoding the second difference value D ″ and the encoding mode output by the mode selecting means, the prediction based on the frame and the prediction based on the motion-compensated reference frame , It is possible to output a coded signal by selecting a code having a minimum code length. Therefore, by utilizing the pixel correlation between frames, the number of bits required for coding can be reduced. Can be reduced.

According to the image encoding apparatus of the present invention (claim 3), there is provided an image encoding apparatus which receives a two-dimensional binary image signal as an input signal and encodes a pixel whose pixel value of the input signal changes. A pixel change means for detecting a pixel whose pixel value changes and outputting the detected change pixel as a detected change pixel; and scanning the image signal in the horizontal direction to thereby encode and decode the image signal. A first prediction unit that predicts a changed pixel of the input signal based on a pixel whose pixel value changes, and outputs the predicted pixel as a first predicted pixel; A first difference value calculating unit that calculates a difference from the first predicted pixel and outputs the calculated difference as a first difference value D, and performs encoding and decoding by scanning the image signal in the vertical direction. Converted image Based on changing pixels of the pixel value, the second prediction means for predicting a change pixel of the input signal, and outputs the pixels the prediction as a second predicted pixel,
A second difference value calculating unit that calculates a difference between the detected change pixel and the second predicted pixel, and outputs the calculated difference as a second difference value D ″; Second
Is calculated for each of the above-mentioned difference values D ″, and the calculation results are compared to select a shorter code length, and the “first” corresponding to the above selection is selected. Or a mode selecting means for outputting any one of "second" as the encoding mode, the selected first difference value D or the second difference value D ", and an encoding mode outputted by the mode selecting means. And the encoding means for encoding the horizontal scanning and the vertical scanning prediction, and it is possible to select and encode the code having the minimum code length. Therefore, the number of bits required for encoding can be reduced by using the local change in the horizontal correlation and the vertical correlation of the image.

According to the image encoding apparatus of the present invention (claim 4), an image encoding apparatus which takes a multi-level image signal as an input signal and encodes a pixel of which the pixel value of the input signal changes is encoded. A changed pixel detecting unit that detects a pixel whose pixel value changes to a predetermined value or more and outputs the detected pixel as a detected changed pixel, and a pixel whose pixel value of an encoded and decoded pixel changes. Predicting means for predicting a changed pixel of the input signal and outputting the predicted pixel as a predicted pixel; calculating a difference between the detected changed pixel and the predicted pixel; and calculating the calculated difference as a difference value D A difference value calculating means for outputting; a coding means for coding the difference value D and a pixel value of the detected change pixel;
And decoding means for decoding a multi-valued image signal from the pixel value of the changed pixel and the pixel value of the changed pixel. It is possible to encode not only multi-valued images but also multi-valued images.

According to the image coding apparatus of the present invention (claim 5), an image signal consisting of a transmittance signal indicating a ratio when combining images and a pixel value signal is used as an input signal, and a reference image is used as a reference image. A coding apparatus for coding the input signal by referring to the first and second pixel values, wherein a pixel value signal of the input signal is compared with a pixel value signal of the reference image to detect a motion vector of the pixel value signal. Motion vector detecting means, first motion compensating means for performing motion compensation on the pixel value signal of the reference image using the motion vector of the pixel value signal, and outputting a compensated pixel value signal; A first difference value calculating means for calculating a difference between the two from the value signal and the compensation pixel value signal and outputting a first difference value; and a first code for encoding the first difference value. , A transmission signal of the input signal, and the reference image. And a second motion vector detecting means for detecting a motion vector of the transparency signal by comparing the transparency signal with the transparency signal of the reference image, and performing motion compensation on the transparency signal of the reference image using the motion vector of the transparency signal. A second motion compensating means for outputting a compensated transmittance signal; and calculating a difference value between the two from the transmittance signal of the input signal and the compensated transmittance signal, and outputting a second difference value. 2, a second encoding means for encoding the second difference value, and a third encoding means for encoding the motion vector of the pixel value signal and the motion vector of the transparency signal. Since the encoding means is provided, the transparency signal is subjected to motion compensation using a motion vector detected separately from the motion vector of the pixel value signal, so that the accuracy of the input transparency signal is improved by the motion compensation signal. Good approximation, movement Since 償誤 difference is reduced, thereby improving the coding efficiency.

According to the image coding apparatus of the present invention (claim 6), in the image coding apparatus of claim 5,
The second motion vector detecting means compares the transmittance signal of the input signal with the transmittance signal of the reference image in the vicinity of the motion vector detected by the first motion vector detecting means, Since the motion vector of the signal is detected, the motion vector of the transmittance signal is detected only near the motion vector of the pixel value signal,
The number of calculations required for motion detection can be reduced as compared with the case where the calculation is performed completely independently of the pixel value signal.

According to the image encoding apparatus of the present invention (claim 7), in the image encoding apparatus of claim 5,
The first motion vector detecting means compares a pixel value signal of the input signal with a pixel value signal of the reference image in the vicinity of the motion vector detected by the second motion vector detecting means. Since the motion vector of the signal is detected, the motion vector of the pixel value signal is detected only near the motion vector of the transmittance signal,
The number of calculations required for motion detection can be reduced as compared to the case where the calculation is performed completely independently of the transmittance signal.

According to the image coding apparatus of the present invention (claim 8), in the image coding apparatus of claim 5,
The third encoding means encodes the motion vector of the pixel value signal and a difference value between the motion vector of the transmittance signal and the motion vector of the pixel value signal. A difference vector of a motion vector of a certain signal is coded. For this reason, the frequency of occurrence of the difference vector is concentrated in the vicinity of the zero vector, and by performing variable length coding, coding efficiency is improved and coding can be performed with a smaller number of bits.

According to the image coding apparatus of the present invention (claim 9), in the image coding apparatus of claim 5,
Since the third encoding means encodes the motion vector of the transparency signal and a difference value between the motion vector of the transparency signal and the motion vector of the pixel value signal, the correlation is A difference vector of a motion vector of a certain signal is encoded. For this reason, the frequency of occurrence of the difference vector is concentrated in the vicinity of the zero vector, and by performing variable length coding, coding efficiency is improved and coding can be performed with a smaller number of bits.

According to the image coding apparatus of the present invention (claim 10), a block comprising a shape signal indicating whether the shape of an object and a pixel value of each pixel is significant, and a pixel value signal. An encoded image signal having an image shape as an input signal, and encoding the input signal with reference to a reference image, wherein the pixel value signal of the input signal and the pixel value signal of the reference image are The first motion vector detecting means for comparing and detecting the motion vector of the pixel value signal, and the pixel value signal of the reference image are motion-compensated using the motion vector of the pixel value signal. The first to output
Motion compensating means, a first difference value calculating means for calculating a difference between the two from the pixel value signal of the input signal and the compensated pixel value signal, and outputting a first difference value; First encoding means for encoding the difference value of the input signal, and second motion vector detecting means for comparing the shape signal of the input signal and the shape signal of the reference image to detect a motion vector of the shape signal. A second motion compensator for motion-compensating the shape signal of the reference image using the motion vector of the shape signal and outputting a compensation shape signal; a shape signal of the input signal; From, the difference between the two is calculated,
Second difference value calculating means for outputting a second difference value, second coding means for coding the second difference value, a motion vector of the pixel value signal, and a motion vector of the shape signal Is provided, so that the coding efficiency can be improved, and in addition, a more appropriate signal that has been coded and decoded as a reference image and to which a motion compensation value has been added is used. This makes it possible to further reduce the motion compensation error.

According to the image coding apparatus of the present invention (claim 11), in the image coding apparatus of claim 10, the second motion vector detecting means is provided with the first motion vector detecting means. In the vicinity of the motion vector detected in the above, the shape signal of the input signal and the shape signal of the reference image are compared to detect the motion vector of the shape signal. By using the result of motion detection in the value signal, the number of calculations for motion detection can be reduced.

According to the image encoding apparatus of the present invention (claim 12), in the image encoding apparatus of claim 10, the first motion vector detecting means is provided with the second motion vector detecting means. The pixel value signal of the input signal is compared with the pixel value signal of the reference image in the vicinity of the motion vector detected in the step (a), and the motion vector of the pixel value signal is detected. Hits the,
By using the result of motion detection in the transmittance signal, the number of calculations for motion detection can be reduced.

According to the image encoding apparatus of the present invention (claim 13), in the image encoding apparatus of claim 10, the third encoding means comprises: a motion vector of the pixel value signal; Since the difference value between the motion vector of the shape signal and the motion vector of the pixel value signal is coded, instead of coding the motion vector of the shape signal,
A difference vector between the motion vector of the pixel value signal and the motion vector of the shape signal is encoded. Therefore, by performing variable-length coding, it is possible to further improve coding efficiency.

According to the image encoding apparatus of the present invention (claim 14), in the image encoding apparatus of claim 10, the third encoding means comprises: a motion vector of the shape signal; Since the difference between the motion vector of the shape signal and the motion vector of the pixel value signal is coded, instead of coding the motion vector of the pixel value signal,
A difference vector between the motion vector of the shape signal and the motion vector of the shape signal is encoded. Therefore, by performing variable-length coding, it is possible to further improve coding efficiency.

According to the image coding apparatus of the present invention (claim 15), in the image coding apparatus of claim 10, the shape signal of the input signal indicates that all pixel values are significant. And the compensation shape signal obtained by motion-compensating the shape signal of the reference image using the motion vector of the pixel value signal detected by the first motion vector detection means indicates that all the pixel values are significant. Or the shape signal of the input signal indicates that the pixel values are all insignificant, and a reference is made using the motion vector of the pixel value signal detected by the first motion vector detection means. If the compensated shape signal obtained by motion-compensating the shape signal of the image indicates that all pixel values are not significant, the second vector detection unit does not detect a motion vector of the shape signal, and With motion vector of the detected pixel value signal in the first vector detection means, since it is assumed that the motion vector of the shape signal, in the case of low needs are is not performed motion detection shape signal. For this reason, the processing load can be reduced.

According to the image encoding apparatus of the present invention (claim 16), in the image encoding apparatus of claim 10, the motion vector of the pixel value signal detected by the first motion vector detecting means is determined by And comparing the shape signal of the reference image with the shape signal of the input signal. If the difference of the comparison result is smaller than a predetermined allowable value, the first vector detecting means is used. Does not detect the motion vector of the pixel value signal, and uses the motion vector of the shape signal detected by the second vector detection means,
Since the motion vector of the pixel value signal was used,
If the necessity is low, the motion detection of the shape signal is not performed. For this reason, the processing load can be reduced.

[0230] According to the image encoding apparatus of the present invention (claim 17), in the image encoding apparatus of claim 10, the third encoding means comprises: When the motion vector of the shape signal of the input signal has been coded, the difference value between the motion vector of the shape signal coded immediately before and the motion vector of the shape signal detected from the input signal is coded. Therefore, if the motion vector of the shape signal has been coded immediately before, a difference vector between the motion vector and the detected motion vector is obtained and coded. For this reason,
By using the difference between the motion vectors of the shape signals having high correlation, it is possible to improve the coding efficiency.

[0231] According to the image encoding apparatus of the present invention (claim 18), in the image encoding apparatus of claim 10, the third encoding means includes: When the motion vector of the pixel value signal of the input signal has been encoded, the difference value between the motion vector of the immediately preceding pixel value signal and the motion vector of the pixel value signal detected from the input signal is encoded. Therefore, if the motion vector of the pixel value signal has been encoded immediately before, a difference vector between the motion vector and the detected motion vector is acquired and encoded. For this reason, it is possible to improve the coding efficiency by using the difference between the motion vectors of the pixel value signals having high correlation.

According to the image coding apparatus of the present invention (claim 19), in the image coding apparatus of any one of claims 10 to 18, the input signal is used for synthesizing a plurality of images. Since the transparency information including the information indicating the composition ratio and the image information, the transparency information is used as the shape signal, and the image information is used as the pixel value signal. In addition, it is possible to improve the coding efficiency of an image signal including transparency information.

According to the image coding apparatus of the present invention (claim 20), in the image coding apparatus of any one of claims 10 to 18, the input signal is used for synthesizing a plurality of images. In the case where the transparency information includes information indicating the combination ratio and image information, the transparency information is converted into a binary signal representing only a shape, and a residual shape signal as another signal. And the above separated 2
Since the value signal is used as the shape signal and the separated residual shape signal and the image information are used as the pixel value signal, encoding efficiency is improved for an image signal including transparency information. It becomes possible.

According to the image encoding apparatus of the present invention (claim 21), the shape information indicating whether the pixel value of each pixel of the object is significant, and the transmission information indicating the synthesis ratio of each pixel of the object. An image coding apparatus using an image signal composed of at least one of the degree information and the pixel value information as an input image signal, wherein one pixel that spatially and temporally matches the input image signal is one. Blocking means integrated as a group and output as blocked information, and the shape information blocked by the blocking means,
A first encoding unit that selects an encoding mode from predetermined encoding modes for each of the transmittance information and the pixel value information, and encodes each of the encoding modes in the selected encoding mode; And second encoding means for collectively encoding mode identification information indicating the selected mode for each of the shape information, the transparency information, and the pixel value information. Since the output of the encoding unit and the output of the second encoding unit are encoded outputs, the shape information, the transparency information, and the pixel value information having high correlation are encoded collectively. . For this reason, by performing variable length coding in which codes having the same mode have a shorter code length, it is possible to reduce the number of bits of the mode coded signal.

According to the image encoding apparatus of the present invention (claim 22), the shape information indicating whether the pixel value of each pixel of the object is significant and the transmission information indicating the synthesis ratio for each pixel of the object. An image coding apparatus using an image signal composed of at least one of the degree information and the pixel value information as an input image signal, wherein one pixel that spatially and temporally matches the input image signal is one. Blocking means for integrating as a group and outputting as blocked information, and the shape information blocked by the blocking means,
A first encoding unit that selects an encoding mode from predetermined encoding modes for each of the transparency information and encodes each of the encoding modes in the selected encoding mode; A second encoding unit that encodes the pixel value information blocked by the blocking unit in any one of the encoding modes selected by the encoding unit; and the shape information; A third encoding unit that collectively encodes the transparency information and the mode identification information indicating the selected mode for each of the pixel value information;
Since the output of the encoding means, the output of the second encoding means, and the output of the third encoding means are the encoded outputs, the selected mode is likely to be the same. For this reason,
By performing variable-length coding, it is possible to further reduce the number of bits of the mode-coded signal.

According to the image coding apparatus of the present invention (claim 23), the shape information indicating whether the pixel value of each pixel of the object is significant and the transmission information indicating the synthesis ratio for each pixel of the object. An image coding apparatus that uses an image signal composed of at least one of the degree information and pixel value information as an input image signal, wherein one pixel that spatially and temporally matches the input image signal is one. Integrating as a group, blocking means for outputting as blocked information, and for the pixel value information blocked by the blocking means, select an encoding mode from a predetermined encoding mode, A first encoding unit that performs encoding in the selected encoding mode, and a block that is blocked by the blocking unit in the encoding mode selected in the first encoding unit. Second encoding means for encoding the shape information information and the transparency information, and a mode identification indicating the selected mode for each of the shape information, the transparency information and the pixel value information. And third encoding means for encoding information collectively, wherein the output of the first encoding means, the output of the second encoding means,
In addition, since the output of the third encoding means is an encoded output, the selected mode is likely to be the same. Therefore, by performing variable-length coding, the number of bits of the mode-coded signal can be further reduced.

According to the image coding apparatus of the present invention (claim 24), in the image coding apparatus of any one of claims 21 to 23, the predetermined coding mode is:
Since intra-frame coding and inter-screen coding are assumed, coding based on the correlation between image signals can be performed, and the number of bits of the mode-coded signal can be reduced.

According to the image coding apparatus of the present invention (claim 25), in the image coding apparatus of claim 22 or 23, the second coding means is provided with the first coding means. In, when the selected encoding mode is intra-screen encoding, since intra-screen encoding is to be selected, encoding based on the correlation between image signals is performed, and the mode is the same. By doing so, the number of bits of the mode-coded signal can be further reduced.

According to the image coding apparatus of the present invention (claim 26), in the image coding apparatus according to any one of claims 21 to 23, the predetermined coding mode is:
Since the number of motion vectors is assumed to be the number of motion vectors for each block, encoding corresponding to the property of the image signal can be performed, and the number of bits of the mode encoded signal can be reduced.

According to the image coding apparatus of the present invention (claim 27), in the image coding apparatus of claim 22 or 23, the second coding means is provided with the first coding means. In, since the number of motion vectors in the selected encoding mode is selected as the encoding mode, by performing encoding corresponding to the properties of the image signal, and by making the mode the same, The number of bits of the mode coded signal can be further reduced.

According to the image coding apparatus of the present invention (claim 28), in the image coding apparatus according to any one of claims 21 to 23, the predetermined coding mode is:
Since it is assumed that the quantization step has been changed and the quantization step has not been changed, it is possible to perform coding corresponding to the property of the image signal and reduce the number of bits of the mode coded signal.

According to the image coding apparatus of the present invention (claim 29), in the image coding apparatus according to claim 22 or 23, the second coding means is the first coding means. In the above, when the selected encoding mode is no quantization step change, since no quantization step change is selected, encoding corresponding to the property of the image signal is performed, and the mode is the same. By doing
The number of bits of the mode coded signal can be further reduced.

According to the image encoding apparatus of the present invention (claim 30), there is provided an image encoding apparatus for inputting and encoding a two-dimensional image signal composed of a plurality of pixels. On the other hand, a first changing pixel detecting unit that detects a pixel whose pixel value changes by scanning in a predetermined direction and outputs the detected first changing pixel, Then, a pixel whose pixel value changes by scanning in a predetermined direction is detected, and the detected second
A second changed pixel detecting unit that outputs a changed pixel, and a pixel whose pixel value changes by scanning the encoded and decoded pixels in a predetermined direction. A third changed pixel detecting means for outputting a changed pixel, and the first changed pixel is predicted based on the second changed pixel and the third changed pixel. Changing pixel predicting means for outputting;
Prediction error calculating means for calculating a difference between the changed pixel and the predicted changed pixel, and outputting the calculated changed pixel difference value; and a prediction error code for coding the changed pixel difference value to obtain an encoded signal. Since the encoding device is provided with an encoding unit, an error in prediction is encoded, and encoding efficiency can be improved.

According to the image coding apparatus of the present invention (claim 31), in the image coding apparatus of claim 30, the second changed pixel detecting means and the third changed pixel detecting means are provided. Is to make the pixel values of the second changed pixel and the third changed pixel the same as the pixel values of the first changed pixel. Can be

According to the image coding apparatus of the present invention (claim 32), in the image coding apparatus of claim 30, the second changed pixel detecting means and the third changed pixel detecting means. Since the predetermined scanning direction is set to be the same as the predetermined scanning direction of the first change pixel detecting means, the encoding is performed, and the above-described effect is obtained.

According to the image coding apparatus of the present invention (claim 33), in the image coding apparatus of claim 30, the difference from the changed pixel predicted using the second changed pixel is Since it is assumed that the third change pixel is coded, the above-described coding is performed, and the above-described effect is obtained.

According to the image coding apparatus of the present invention (claim 34), in the image coding apparatus of claim 30, the second changed pixel, the third changed pixel, and the first changed pixel. Are on different scanning lines, the above coding is performed, and the above effects can be obtained.

According to the image coding apparatus of the present invention (claim 35), in the image coding apparatus of claim 30, the changed pixel predicting means determines that the second changed pixel is the second changed pixel.
When the third change pixel is at the x-th pixel of the m-th scan line and the third change pixel is at the y-th pixel of the n-th scan line, for the first change pixel, y- (xy) * (nk) of the k-th scan line ) / (mn) pixel is predicted, so that the above coding is performed, and the above effects can be obtained.

According to the image encoding apparatus of the present invention (claim 36), there is provided an image encoding apparatus for inputting and encoding a two-dimensional image signal composed of a plurality of pixels. On the other hand, a pixel whose pixel value changes by scanning in a predetermined direction is detected, and a changed pixel detecting means for outputting the detected detected changed pixel, and a changed pixel is predicted from the coded and decoded pixels. A changed pixel prediction unit that outputs the predicted predicted changed pixel, a prediction error calculation unit that calculates a difference between the detected changed pixel and the predicted changed pixel, and outputs the calculated changed pixel difference value, A prediction error encoding unit that encodes the changed pixel difference value when the value of the changed pixel difference value is less than a predetermined value, and outputs a difference value encoded signal; If it is more than Calculate the number of pixels that are located between the previously coded changed pixel and the detected changed pixel and are not located at a pixel position that can be coded by the prediction error coding unit, and calculate the calculated number of pixels. Pixel number encoding means for encoding and outputting a pixel number encoded signal,
Since the prediction error encoding unit and the pixel number encoding unit perform encoding in which the difference value encoded signal and the pixel number encoded signal can be uniquely identified, the prediction error is determined. When within the range, the encoded signal of the prediction error is
When it is out of the range, the encoded signal of the number of pixels is set as the encoded signal to be output. For this reason, when the prediction error is large, it is possible to prevent a decrease in the coding efficiency and perform appropriate coding even when the change pixel cannot be predicted due to a change in the number of the change pixels. Becomes

According to the image encoding apparatus of the present invention (claim 37), in the image encoding apparatus of claim 36, the prediction error encoding means and the pixel number encoding means are adapted to execute the change The predetermined value to be compared with the pixel difference value is
Since the setting was made using the number of pixels of the scanning line,
By performing the above coding, the above effects can be obtained.

According to the image coding apparatus of the present invention (claim 38), an image coding apparatus which inputs a two-dimensional shape signal representing an area where a pixel representing an object is present and encodes the shape signal And from the input shape signal,
A significant area extraction unit that extracts a significant area that is a rectangular area including the pixel representing the object, and outputs a significant area range that is a range of the extracted significant area; and converts the shape signal into a block including a plurality of pixels. For each of the blocking means to be divided and each block output by the blocking means,
Determining whether or not to include the significant region, and when determining to include the significant region, at least encoding the significant region of the block, and comprising a shape encoding means for outputting a shape encoded signal, Since the significant area range and the shape-encoded signal are used as encoded signals, the significant area range is detected, and the block size of the shape signal is changed so that the shape signal is encoded only inside the significant area range. It will be.
Therefore, coding outside the range of the significant region is not performed, and coding efficiency of the shape signal is improved.

According to the image coding apparatus of the present invention (claim 39), in the image coding apparatus according to claim 38, the shape coding means is provided in each block constituted by the blocking means. , The smallest rectangular area including the significant area is extracted, and only the inside of the extracted rectangular area is encoded. Therefore, the encoding is performed to improve the encoding efficiency.

According to the image encoding apparatus of the present invention (claim 40), there is provided an image encoding apparatus for encoding a two-dimensional image signal by inputting a two-dimensional image signal comprising a plurality of pixels. Image signal separating means for separating the image signal into at least two image signals and outputting the separated image signals as two or more partial image signals; and at least one of the partial image signals as a target partial image signal A first image signal encoding unit for selecting and encoding the selected target partial image signal and outputting a first encoded signal; and an image signal obtained by decoding the first encoded signal. Prediction probability calculating means for predicting a non-target partial image signal of the partial image signal excluding the target partial image signal, calculating a probability that the prediction is successful, and outputting the calculated prediction probability; A second determining unit that determines a decoding priority in accordance with the prediction probability calculated by the prediction probability calculation unit and encodes the non-target partial image signal using an encoding method corresponding to the determined priority path; Since the image signal encoding means is provided, priority is given to encoding from pixels having a low prediction probability, so that hierarchical encoding with little image quality degradation can be realized without additional information.

[0254] According to the image coding apparatus of the present invention (claim 41), in the image coding apparatus of claim 40, the second image signal coding means determines whether the pixel having the small prediction probability is a pixel having a small prediction probability. Since the priority of the decoding is determined so as to be preferentially decoded, the above-described encoding is performed, and the above-described effect is obtained.

According to the picture coding apparatus of the present invention (claim 42), in the picture coding apparatus according to claim 40, the prediction probability calculating means is arranged such that when neighboring pixel values have the same value, The probability of hitting is large, and when the neighboring pixel values are different, the probability of hitting is small. Therefore, the above coding is performed, and the above effects are obtained.

[0256] According to the image decoding apparatus of the present invention (claim 43), there is provided an image decoding apparatus for receiving a coded signal and decoding the coded signal. A decoding unit that obtains a mode and a difference value, outputs the obtained difference value as a decoding difference value using the obtained coding mode as a mode signal, and a coding unit that has already coded and decoded the pixel in the frame. A first prediction unit that predicts a changed pixel of the input signal based on a pixel whose pixel value changes, and outputs the predicted pixel as a first predicted pixel; A second prediction unit that predicts a changed pixel of the input signal based on a pixel whose pixel value changes, with motion compensation, and outputs the predicted pixel as a second predicted pixel; Mo When the signal indicates the frame prediction, the decoding difference value is added to the first prediction pixel. When the mode signal indicates the reference frame prediction, the decoding difference value is added to the second prediction pixel. Since the output of the adding means is a changed pixel, the coded signal obtained by the image coding apparatus according to claim 2 can be appropriately decoded.

According to the image decoding apparatus of the present invention (claim 44), there is provided an image decoding apparatus for receiving a coded signal and decoding the coded signal. A decoding unit that acquires a mode and a difference value, and outputs the acquired difference value as a decoding difference value by using the acquired encoding mode as a mode signal, and scanning the image signal in the horizontal direction. A first prediction unit that predicts a changed pixel of the input signal based on a pixel whose pixel value of an encoded and decoded pixel changes, and outputs the predicted pixel as a first predicted pixel; By scanning the image signal in the vertical direction, a changed pixel of the input signal is predicted based on a pixel having a changed pixel value of the encoded and decoded pixel, and the predicted pixel is determined as a second predicted pixel. Out as When the mode signal indicates the prediction of the horizontal scanning, the decoding difference value is added to the first prediction pixel, and when the mode signal indicates the prediction of the vertical scanning, And an adding means for adding the decoding difference value to the second predicted pixel, and the output of the adding means is used as a changed pixel, so that the coded signal obtained by the image coding apparatus of Can be decrypted.

[0258] According to the image decoding apparatus of the present invention (claim 45), there is provided an image decoding apparatus for receiving a coded signal and decoding the coded signal. And decoding means for obtaining the pixel value of the changed pixel, outputting the obtained difference value as a decoded difference value, and outputting the obtained pixel value of the changed pixel as a decoded pixel value. Based on the pixel whose value changes, predicting a changed pixel of the input coded signal, predicting means for outputting the predicted pixel as a predicted pixel, adding the decoded difference value and the predicted pixel, The image processing apparatus includes an adding unit that outputs a result of the addition as a corrected difference value, and an image decoding unit that obtains a multilevel image signal by a decoding process from the corrected difference value and the decoded pixel value. The image code according to claim 4, It can be properly decode the encoded signal obtained in the apparatus.

According to the image decoding apparatus of the present invention (claim 46), there is provided an image decoding apparatus for inputting and decoding an encoded signal, wherein a difference value of a pixel value signal from the encoded signal is obtained. And outputs a decoded pixel value difference value
Decoding means, a second decoding means for decoding the difference value of the transmittance signal from the coded signal, and outputting as a decoded transmittance difference value, a motion vector of a pixel value signal from the coded signal, A third decoding unit that decodes a motion vector of the transparency signal and outputs a decoded pixel value motion vector and a decoded transparency motion vector, and a pixel value signal of a reference image described later, First motion compensating means for performing motion compensation using the above, and outputting the result of the motion compensation as a compensated pixel value signal, adding the decoded pixel value difference value and the compensated pixel value signal, and decoding the added result First addition means for outputting as a pixel value signal of the reference image and also outputting as a pixel value signal of the reference image, and a transparency signal of a reference image, which will be described later, is subjected to motion compensation using the decoded transmittance motion vector. Second motion compensating means for outputting the result of the motion compensation as a compensated transmittance signal, adding the decoded transmittance difference value and the compensated transmittance signal, and outputting the sum as a decoded transmittance signal Along with
Since the image processing apparatus includes the second addition unit that outputs the reference image as a transparency signal, the encoded signal obtained by the image encoding device according to claim 5 can be appropriately decoded.

According to the image decoding apparatus of the present invention (claim 47), in the image decoding apparatus of claim 46, the third decoding means comprises a motion vector of a pixel value signal, Decoding the vector difference value to obtain a decoded pixel value motion vector and a decoded motion vector difference value, and adding the decoded pixel value motion vector and the decoded motion vector difference value to obtain the decoded transparency motion vector Therefore, the encoded signal obtained by the image encoding device according to claim 7 can be appropriately decoded.

As described above, according to the present invention, unlike the MMR coding according to the prior art, even in lossless lossless coding, the compression rate can be greatly increased by allowing visually insignificant image quality deterioration. It is possible to improve.

Also, according to the present invention, the conventional technology
Compared to MMR, which uses only intra-screen and horizontal correlation, encoding can also be performed using inter-screen correlation and vertical correlation, thus improving coding efficiency. It becomes possible to plan.

Also, according to the present invention, the conventional technology
MMR and coded data that can be reproduced hierarchically by decoding a part of the bit stream, which could not be achieved by MMMR, can be realized without lowering the coding efficiency And an encoding method that enables the objective image reproduction.

According to the present invention, when an image consisting of shape information and pixel value information is encoded by motion compensation,
Since a motion vector is used for each of them, by performing motion compensation using the same motion vector as in the encoding according to the related art, it is possible to avoid that appropriate encoding cannot be performed. Further, by using the correlation of these motions, it is possible to improve the coding efficiency.

According to the present invention, when an image composed of shape information and pixel value information is encoded by adaptively switching between intra-picture encoding and inter-picture encoding, the properties of each information , Such switching can be performed, and appropriate and efficient encoding can be performed. Similarly, it is also possible to adaptively change the number of motion vectors, or to adaptively switch whether or not to change the quantization step, according to the nature of each piece of information.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 1 of the present invention.

FIG. 2 is a diagram for explaining an operation principle of the image encoding device according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of an image encoding device according to a second embodiment of the present invention.

FIG. 4 is a diagram for explaining an operation principle of an image encoding device according to a second embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of an image decoding device according to a third embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of another example of an image decoding device according to Embodiment 3 of the present invention.

FIG. 7 is a block diagram illustrating a configuration of an image encoding device according to a fourth embodiment of the present invention.

FIG. 8 is a diagram for explaining an operation principle of an image encoding device according to a fourth embodiment of the present invention.

FIG. 9 is a block diagram illustrating a configuration of an image decoding device according to a fifth embodiment of the present invention.

FIG. 10 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 6 of the present invention.

FIG. 11 is a block diagram illustrating a configuration of an image decoding device according to a seventh embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of an image encoding device according to Embodiment 8 of the present invention.

FIG. 13 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 9 of the present invention.

FIG. 14 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 10 of the present invention.

FIG. 15 is a block diagram showing a configuration of an image decoding device according to Embodiment 11 of the present invention.

FIG. 16 is a block diagram illustrating a configuration of an image decoding device according to a twelfth embodiment of the present invention.

FIG. 17 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 13 of the present invention.

FIG. 18 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 14 of the present invention.

FIG. 19 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 15 of the present invention.

FIG. 20 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 16 of the present invention.

FIG. 21 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 17 of the present invention.

FIG. 22 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 18 of the present invention.

FIG. 23 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 19 of the present invention.

FIG. 24 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 20 of the present invention.

FIG. 25 is a block diagram illustrating a configuration of an image decoding device according to Embodiment 21 of the present invention.

FIG. 26 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 22 of the present invention.

FIG. 27 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 23 of the present invention.

FIG. 28 is a diagram for describing selection of the number of motion vectors in the image encoding device according to Embodiment 23 of the present invention.

FIG. 29 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 24 of the present invention.

FIG. 30 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 25 of the present invention.

FIG. 31 is a diagram for describing an operation principle of an image coding device according to a twenty-fifth embodiment of the present invention.

FIG. 32 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 26 of the present invention.

FIG. 33 is a diagram for describing an operation principle of an image coding device according to a twenty-seventh embodiment of the present invention.

FIG. 34 is a diagram for describing an operation principle of an image encoding device according to a twenty-eighth embodiment of the present invention.

FIG. 35 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 29 of the present invention.

FIG. 36 is a diagram for describing an operation principle of an image coding device according to a twenty-ninth embodiment of the present invention.

FIG. 37 is a block diagram illustrating a configuration of an image decoding device according to Embodiment 30 of the present invention.

FIG. 38 is a block diagram illustrating a configuration of an image decoding device according to Embodiment 31 of the present invention.

FIG. 39 is a block diagram illustrating a configuration of an image decoding device according to Embodiment 32 of the present invention.

FIG. 40 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 33 of the present invention.

FIG. 41 is a diagram for describing an operation principle of an image encoding device according to a thirty-third embodiment of the present invention.

FIG. 42 is a block diagram illustrating a configuration of an image decoding device according to Embodiment 34 of the present invention.

FIG. 43 is a diagram for describing setting of a prediction range in an image encoding device and an image decoding device according to Embodiment 35 of the present invention.

FIG. 44 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 36 of the present invention.

[Fig. 45] Fig. 45 is a diagram for describing the operation principle of the image coding device according to the embodiment 36 of the present invention.

FIG. 46 is a block diagram illustrating a configuration of an image decoding device according to a thirty-seventh embodiment of the present invention.

FIG. 47 is a block diagram illustrating a configuration of an image encoding device according to Embodiment 38 of the present invention.

FIG. 48 is a diagram for describing an operation principle of an image encoding device according to a thirty-eighth embodiment of the present invention.

FIG. 49 is a block diagram illustrating a configuration of an image decoding device according to Embodiment 39 of the present invention.

FIG. 50 is a diagram illustrating a floppy disk which is an example of a recording medium of an image encoding program and an image decoding program according to Embodiment 40 of the present invention.

FIG. 51 is a flowchart showing a processing procedure of an image coding program according to Embodiment 40 of the present invention.

FIG. 52 is a flowchart showing a processing procedure of an image decoding program according to Embodiment 40 of the present invention.

FIG. 53 is a diagram for describing image shape information in image encoding.

[Explanation of symbols]

1, 1a, 201, 211, 255 Input signal 2, 2a, 2b, 204a, 204b Changed pixel detector 3, 61, 95, 202a, 202b, 216a, 21
6b, 220 Memory 4, 4a, 4b Change pixel predictor 5, 5a, 5b Difference value calculator 6 Allowable value 7 Difference value rounder 8, 8a, 8b, 65a, 65b, 67a, 67b, 2
10,242,418,414 Encoder 9,9a, 9b, 30a, 30b, 66a, 66b, 6
8a, 68b, 80a, 80b, 82a, 82b, 21
1, 243, 419, 415 Coded signal 10 Changing pixel decoder 11, 11a, 11b, 75a, 75b, 84a, 84
b, 86 Difference value adder 20, 63a, 63b Motion compensator 21 Mode selector 22, 32, 33, 50 Switcher 31a, 31b, 81a, 81b, 83a, 83b, 2
30, 310, 316a, 316b, 330 Decoder 34, 85a, 85b, 101, 235 Image signal 40a, 40b Horizontal scanner 41a, 41b Vertical scanner 60a, 107 Pixel value signal 60b, 105 Transmittance signal (input shape) Signals) 62a, 62b Motion detectors 64a, 64b, 70 Difference value calculator 90 Motion detection determiner 93 Switching determiner 94 Switcher 102, 404 Blocking device 103 Shape signal 110 Shape coding mode determiner 111, 151 Shape code Encoding mode 112 shape encoder 113 shape encoded signal 114 transparency encoding mode determiner 115, 153 transparency encoding mode 116 transparency encoder 117 transparency encoded signal 118 pixel value encoding mode determiner 119, 155 pixel value encoding mode 120 pixel value encoder 121 pixels Value coded signal 122 Mode coder 123 Mode coded signal 130, 136 Transparency coding mode determiner 132 Pixel value coding mode determiner 138 Shape coding mode determiner 150 Mode decoder 156 Shape decoder 158 Transparency decoder 160 Pixel value decoder 157 Shape decoded signal 159 Transparency decoded signal 161 Pixel value decoded signal 162 Deblocker 163 Decoded image signal 170, 176, 180, 186, 190, 196 Switch 172 , 178 In-screen / inter-screen coding determiner 173 Shape coding mode 182 Shape motion vector number determiner 183,193 Shape signal coding mode 188 Motion vector number determiner for pixel value coding 192 Shape coding Quantization step change / non-change decision unit 198 Quantization of pixel value coding Step change / non-change determination unit 203a Second detection change pixel (reference signal) 203b Third detection change pixel (reference signal) 204c First change pixel detector 205a, 205b Change pixel 205c First detection change pixel 206 Changed pixel predictor 207 Predicted changed pixel 208 Subtractor 209 Prediction error 221 Delayed prediction error 222, 224, 232 Adder 225 Addition value 231 Decoding prediction error 233 Decoded change pixel 234 Pixel value generator 240 Subtractor 241 Difference 243, 247 Code Signal 244 Comparator 246, 426 Switch 250 Mode decoder 251 Encoding mode 256 Pixel number decoder 257 Number of decoded pixels 258 Adder 252, 260, 408 Switch 300 Separator 301a, 301b Image signal 302, 308a, 308b encoder 03a Encoded signal 304, 312 Prediction probability calculator 305 Probability value 306 Second separator 307a, 307b Image signal separation 311, 317a, 317b Decoded signal 313 Probability value 320 Predictor 322 Switch 331 Decoded image signal (predicted image signal ) 401 Input signal (two-dimensional shape signal) 402 Significant region extractor 403 Significant region signal 405 Blocked shape signal 412 Block size changer 413 Blocked shape signal 420 Significant region signal decoder 422 Shape signal decoder 421 Decoded significant area signal 423 Minimum blocked decoded shape signal 427 Blocked shape signal 430 Block size changer 431 Decoded blocked shape signal 432 Deblocked block 433 Decoded shape signal 1001, 1002, 1004, 1006, 1008 ~
1020, 1022 to 1026, 1029, 1033
1036, 1038 Image coding device 1003, 1003a, 1005, 1007, 102
1,1030-1032,1034,1037,103
9 Image decoding device

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 8-21095 (32) Priority date August 9, 1996 (August 8, 1996) (33) Priority claim country Japan (JP)

Claims (47)

[Claims] 1. An image encoding apparatus which receives a binary image signal as an input signal and encodes a pixel of which the pixel value of the input signal changes, detects the pixel of which the pixel value changes, and detects the detected pixel. Changing pixel detection means for outputting a changed pixel as a detected changed pixel; and predicting a changed pixel of the input signal based on a pixel having a changed pixel value of the coded and decoded pixel, and predicting the predicted pixel. Prediction means for outputting as a pixel; a difference value calculation means for calculating a difference between the detected change pixel and the predicted change pixel to output a difference value D; a predetermined allowable value; A rounding means for selecting a value D 'which is a value within a range determined based on the value D and which has a minimum code length at the time of encoding, and outputs this as a modified difference value; And the above-mentioned corrected difference value D ' 2 from the predicted change pixels
An image coding apparatus, comprising: decoding means for decoding a value image signal; and coding means for coding the modified difference value D ′. 2. An image encoding apparatus which receives a binary image signal as an input signal and encodes a pixel of which the pixel value of the input signal changes, detects the pixel of which the pixel value changes, and detects the detected pixel. Changing pixel detection means for outputting a changed pixel as a detected changed pixel; and predicting a changed pixel of the input signal on the basis of a pixel having a changed pixel value among the encoded and decoded pixels in the frame. A first prediction unit that outputs the calculated pixel as a first prediction pixel, calculates a difference between the detected change pixel and the first prediction pixel, and outputs the calculated difference as a first difference value D First difference value calculating means, and, based on a pixel whose pixel value has changed in the coded and decoded pixels in the reference frame, predicting a change pixel of the input signal with motion compensation, and Picture A second prediction means for outputting a difference between the detected change pixel and the second prediction pixel, and outputting the calculated difference as a second difference value D ″. , And calculates a code length when each of the first difference value D and the second difference value D ″ is coded, and compares the calculation results to obtain a code length. Mode selecting means for selecting the shorter one and outputting either "first" or "second" as the encoding mode in response to the selection; and selecting the first difference value D or 2 difference value D ″
And an encoding means for encoding the encoding mode output by the mode selection means. 3. An image encoding apparatus which receives a two-dimensional binary image signal as an input signal and encodes a pixel whose pixel value of the input signal changes, detecting the pixel whose pixel value changes, A changed pixel detecting unit that outputs the detected changed pixel as a detected changed pixel, and scans the image signal in the horizontal direction to thereby determine the input value based on the pixel whose pixel value of the coded and decoded pixel changes. A first predictor for predicting a changed pixel of the signal and outputting the predicted pixel as a first predicted pixel; calculating a difference between the detected changed pixel and the first predicted pixel; And a first difference value calculating unit that outputs the first difference value D as a first difference value D. By scanning the image signal in the vertical direction, based on a pixel whose pixel value of an encoded and decoded pixel changes, Input above A second prediction means for predicting a changed pixel of the signal and outputting the predicted pixel as a second predicted pixel; calculating a difference between the detected changed pixel and the second predicted pixel; As a second difference value D ″, and a code length when each of the first difference value D and the second difference value D ″ is encoded Mode selection means for comparing the calculation results and selecting the one having a shorter code length, and outputting either “first” or “second” as an encoding mode in response to the selection; The selected first difference value D or second difference value D ″
And an encoding means for encoding the encoding mode output by the mode selection means. 4. An image encoding apparatus which receives a multi-valued image signal as an input signal and encodes a pixel of which the pixel value of the input signal changes, detects a pixel whose pixel value changes to a predetermined value or more. A changed pixel detecting unit that outputs the detected pixel as a detected changed pixel; and a predicting a changed pixel of the input signal based on a pixel having a changed pixel value of the coded and decoded pixel. A prediction unit that outputs a pixel as a prediction pixel; a difference value calculation unit that calculates a difference between the detected change pixel and the prediction pixel; and outputs the calculated difference as a difference value D; Encoding means for encoding the pixel value of the detected changed pixel; and decoding means for decoding a multi-valued image signal from the difference value D and the pixel value of the changed pixel. Image coding device. 5. An image signal comprising a transmittance signal indicating a ratio at the time of combining images and a pixel value signal is used as an input signal.
An image encoding device that encodes the input signal with reference to a reference image, comprising comparing a pixel value signal of the input signal with a pixel value signal of the reference image, and calculating a motion vector of the pixel value signal. First motion vector detecting means for detecting, first motion compensating means for performing motion compensation on the pixel value signal of the reference image using the motion vector of the pixel value signal, and outputting a compensated pixel value signal; A first calculating unit calculates a difference between the pixel value signal of the input signal and the compensated pixel value signal and outputs a first difference value.
A difference value calculating means, a first encoding means for encoding the first difference value, a transparency signal of the input signal and a transparency signal of the reference image, Second motion vector detecting means for detecting a motion vector of the reference image; and a second motion compensation unit for motion-compensating the transmittance signal of the reference image using the motion vector of the transmittance signal and outputting a compensated transmittance signal. Means, a second difference value calculating means for calculating a difference value between the two from the transmittance signal of the input signal and the compensation transmittance signal, and outputting a second difference value; An image code comprising: a second encoding unit that encodes a value; a third encoding unit that encodes a motion vector of the pixel value signal and a motion vector of the transparency signal. Device. 6. The image encoding apparatus according to claim 5, wherein said second motion vector detecting means is configured to transmit the input signal in the vicinity of the motion vector detected by said first motion vector detecting means. An image coding apparatus for comparing a signal with a transmittance signal of the reference image to detect a motion vector of the transmittance signal. 7. The image encoding apparatus according to claim 5, wherein the first motion vector detecting means includes a pixel value of the input signal in the vicinity of the motion vector detected by the second motion vector detecting means. An image coding apparatus for comparing a signal with a pixel value signal of the reference image to detect a motion vector of the pixel value signal. 8. The image encoding apparatus according to claim 5, wherein the third encoding unit comprises: a motion vector of the pixel value signal; a motion vector of the transparency signal; and a motion vector of the pixel value signal. An image encoding device for encoding a difference value between the image and the image. 9. The image encoding apparatus according to claim 5, wherein said third encoding means comprises: a motion vector of the transparency signal; a motion vector of the transparency signal; and a motion vector of the pixel value signal. An image encoding device for encoding a difference value between the image and the image. 10. A block-shaped image signal composed of a shape signal indicating whether the shape of an object and a pixel value of each pixel is significant and a pixel value signal is set as an input signal, and a reference image is set as a reference image. An image encoding apparatus for encoding said input signal with reference to a pixel value signal of said input signal and a pixel value signal of said reference image, wherein a motion vector of the pixel value signal is detected. 1 motion vector detecting means, first motion compensating means for performing motion compensation on the pixel value signal of the reference image using the motion vector of the pixel value signal, and outputting a compensated pixel value signal; Calculating a difference between the pixel value signal and the compensated pixel value signal, and outputting a first difference value;
A difference value calculating means, a first encoding means for encoding the first difference value, a shape signal of the input signal and a shape signal of the reference image, and a motion vector of the shape signal Second motion vector detecting means for detecting the input signal; second motion compensating means for performing motion compensation on the shape signal of the reference image using the motion vector of the shape signal; and outputting a compensated shape signal; From the shape signal of the above and the compensation shape signal,
Second difference value calculating means for calculating a difference value between the two, and outputting a second difference value; second coding means for coding the second difference value; and a motion vector of the pixel value signal And a third encoding means for encoding the motion vector of the shape signal. 11. The image encoding apparatus according to claim 10, wherein said second motion vector detecting means includes a shape signal of said input signal in the vicinity of a motion vector detected by said first motion vector detecting means. An image encoding device for comparing a shape signal of the reference image with a shape signal of the reference image to detect a motion vector of the shape signal. 12. The image coding apparatus according to claim 10, wherein said first motion vector detecting means includes a pixel value of said input signal in the vicinity of a motion vector detected by said second motion vector detecting means. An image coding apparatus for comparing a signal with a pixel value signal of the reference image to detect a motion vector of the pixel value signal. 13. The image encoding apparatus according to claim 10, wherein said third encoding means comprises: a motion vector of said pixel value signal; a motion vector of said shape signal; and a motion vector of said pixel value signal. An image encoding apparatus for encoding a difference value between the two. 14. The image encoding apparatus according to claim 10, wherein said third encoding means comprises: a motion vector of the shape signal; and a motion vector of the shape signal and a motion vector of the pixel value signal. An image encoding apparatus for encoding a difference value. 15. The image coding apparatus according to claim 10, wherein the shape signal of the input signal indicates that all pixel values are significant, and is detected by the first motion vector detecting means. If the compensated shape signal obtained by motion-compensating the shape signal of the reference image using the motion vector of the pixel value signal obtained indicates that all pixel values are significant, or the shape signal of the input signal is a pixel value Are not significant, and the compensation shape signal obtained by motion-compensating the shape signal of the reference image by using the motion vector of the pixel value signal detected by the first motion vector detection means has a pixel value Are not significant, the second vector detection means does not detect the motion vector of the shape signal, and the pixel value detected by the first vector detection means No. of with motion vector, the image coding apparatus, characterized in that it is an motion vector of the shape signal. 16. The image coding apparatus according to claim 10, wherein the shape signal of the reference image is motion-compensated using the motion vector of the pixel value signal detected by the first motion vector detection means. Is compared with the shape signal of the input signal, and when the difference between the comparison results is smaller than a preset allowable value, the first vector detection unit does not detect a motion vector of the pixel value signal, 2. An image coding apparatus according to claim 1, wherein the motion vector of the shape signal detected by the second vector detecting means is used as the motion vector of the pixel value signal. 17. The image encoding apparatus according to claim 10, wherein said third encoding means encodes a motion vector of a shape signal of the input signal in an input signal encoded immediately before. In this case, the image encoding apparatus encodes a difference value between the motion vector of the shape signal encoded immediately before and the motion vector of the shape signal detected from the input signal. 18. The image encoding apparatus according to claim 10, wherein said third encoding means encodes a motion vector of a pixel value signal of the input signal in an input signal encoded immediately before. An encoding apparatus for encoding a difference value between a motion vector of a pixel value signal encoded immediately before and a motion vector of a pixel value signal detected from an input signal. 19. The image encoding apparatus according to claim 10, wherein the input signal includes transparency information including information indicating a combination ratio for combining a plurality of images, and image information. Wherein the transparency information is used as the shape signal and the image information is used as the pixel value signal. 20. The image encoding apparatus according to claim 10, wherein the input signal includes transparency information including information indicating a combination ratio for combining a plurality of images, and image information. When the transmittance information is composed of the following, the transparency information is separated into a binary signal representing only the shape and a residual shape signal that is another signal, and the separated binary signal is used as the shape signal. An image coding apparatus, wherein the separated residual shape signal and the image information are used as the pixel value signal. 21. It is composed of shape information indicating whether the pixel value of each pixel of the object is significant, at least one of transparency information indicating a composition ratio of each pixel of the object, and pixel value information. An image coding apparatus using an image signal as an input image signal, comprising: a block that integrates spatially and temporally matching pixels into one group with respect to the input image signal and outputs the grouped information. Means, for each of the shape information, the transparency information, and the pixel value information that have been blocked by the blocking means, select an encoding mode from a predetermined encoding mode, and First encoding means for encoding each in the encoding mode; and the selected mode for each of the shape information, the transparency information, and the pixel value information. Second encoding means for collectively encoding the mode identification information indicating the mode identification information, wherein the output of the first encoding means and the output of the second encoding means are encoded outputs. An image encoding device characterized by the following. 22. The pixel information includes at least one of shape information indicating whether a pixel value of each pixel of the object is significant, transparency information indicating a composition ratio of each pixel of the object, and pixel value information. An image coding apparatus using an image signal as an input image signal, comprising: a block that integrates spatially and temporally matching pixels into one group with respect to the input image signal and outputs the grouped information. Means, for each of the shape information and the transparency information blocked by the blocking means, select an encoding mode from a predetermined encoding mode, and in the selected encoding mode, A first encoding unit that encodes the first and second blocks, and the encoding unit selects one of the encoding modes selected by the first encoding unit. Second encoding means for encoding the pixel value information blocked by a stage; mode identification information indicating the selected mode for each of the shape information, the transparency information, and the pixel value information And third encoding means for encoding the output of the first encoding means, and the output of the first encoding means, the output of the second encoding means, and the output of the third encoding means are encoded outputs. An image encoding device, characterized in that: 23. The pixel information includes at least one of shape information indicating whether a pixel value of each pixel of the object is significant, transparency information indicating a composition ratio of each pixel of the object, and pixel value information. An image encoding device that uses an image signal as an input image signal, wherein each pixel of the input image signal is based on a correspondence between the shape information or the transmittance information and the pixel value information.
A blocking unit that blocks corresponding pixels as a group and outputs the information as blocked information; and encoding the pixel value information blocked by the blocking unit from a predetermined encoding mode. A first encoding unit for selecting a mode and encoding in the selected encoding mode; and the shape blocked by the blocking unit in the encoding mode selected in the first encoding unit. Information information, and second encoding means for encoding the transparency information, and for each of the shape information, the transparency information, and the pixel value information, mode identification information indicating the selected mode, A third encoding unit that encodes the output of the first encoding unit, the output of the second encoding unit, and the third encoding unit. Image encoding apparatus characterized by a coded output the Goka means output. 24. The image coding apparatus according to claim 21, wherein the predetermined coding mode is intra-screen coding and inter-screen coding. apparatus. 25. The image coding apparatus according to claim 22, wherein said second coding means is said first coding means, and said selected coding mode is intra-screen coding. An image encoding apparatus for selecting intra-screen encoding when the image encoding is performed. 26. The image encoding apparatus according to claim 21, wherein the predetermined encoding mode is the number of motion vectors for each block. 27. The image coding apparatus according to claim 22, wherein said second coding means sets said number of motion vectors in said selected coding mode in said first coding means. , An image encoding apparatus for selecting an encoding mode. 28. The image encoding apparatus according to claim 21, wherein the predetermined encoding mode includes a quantization step change and no quantization step change. Encoding device. 29. The image encoding device according to claim 22, wherein the second encoding unit is configured to set the selected encoding mode to the first encoding unit without changing the quantization step. An image coding apparatus, wherein, when there is, the quantization step is not changed. 30. An image encoding apparatus for inputting and encoding a two-dimensional image signal composed of a plurality of pixels, wherein said two-dimensional image signal is scanned in a predetermined direction to change a pixel value. A first changed pixel detecting means for detecting a pixel to be changed and outputting the detected first changed pixel; and scanning the encoded and decoded pixel in a predetermined direction to change the pixel value. A second changed pixel detecting means for detecting a pixel and outputting the detected second changed pixel; and changing the pixel value by scanning the encoded and decoded pixels in a predetermined direction. Detect pixel,
A third changed pixel detecting means for outputting the detected third changed pixel; a first changed pixel predicted based on the second changed pixel and the third changed pixel; Changed pixel prediction means for outputting a predicted changed pixel, a prediction error calculation means for calculating a difference between the first changed pixel and the predicted changed pixel, and outputting the calculated changed pixel difference value; An image encoding apparatus, comprising: a prediction error encoding unit that encodes a changed pixel difference value to generate an encoded signal. 31. The image coding apparatus according to claim 30, wherein said second changed pixel detecting means and said third changed pixel detecting means are: said second changed pixel and said third changed pixel. An image coding apparatus, wherein the pixel value of a pixel is the same as the pixel value of the first changed pixel. 32. The image encoding apparatus according to claim 30, wherein said second changed pixel detecting means and said third changed pixel detecting means determine the predetermined scanning direction by the first change. An image coding apparatus, wherein the pixel detecting means sets the same direction as the predetermined scanning direction. 33. The image coding apparatus according to claim 30, wherein the third changed pixel is coded by a difference from a changed pixel predicted using the second changed pixel. An image encoding device, characterized in that: 34. The image coding apparatus according to claim 30, wherein the second changed pixel, the third changed pixel, and the first changed pixel are on different scanning lines. Encoding device. 35. The image coding apparatus according to claim 30, wherein the changed pixel predicting means is configured such that the second changed pixel is located at the x-th pixel of the m-th scanning line, and the third changed pixel is located at the xth pixel. When the pixel is located at the y-th pixel of the n-th scanning line, the above-mentioned first changed pixel is calculated by y- (xy) * (n-
An image encoding device characterized by predicting that the pixel is the kth / (mn) th pixel. 36. An image encoding apparatus for inputting and encoding a two-dimensional image signal composed of a plurality of pixels, wherein the two-dimensional image signal is scanned in a predetermined direction to change a pixel value. A changed pixel detecting unit that detects a pixel to be changed and outputs the detected detected changed pixel; and a changed pixel predicting unit that predicts the changed pixel from the encoded and decoded pixels and outputs the predicted predicted changed pixel. A prediction error calculating unit that calculates a difference between the detected changed pixel and the predicted changed pixel, and outputs the calculated changed pixel difference value, when the value of the changed pixel difference value is less than a predetermined value. A prediction error encoding unit that encodes the changed pixel difference value and outputs a difference value encoded signal; and, when the value of the changed pixel difference value is equal to or greater than a predetermined value, from the immediately preceding changed pixel, Above detection change Calculate the number of pixels that are located before the pixel and are not located at a pixel position that can be encoded by the prediction error encoding unit, encode the calculated number of pixels, and output a pixel number encoded signal The prediction error encoding means and the pixel number encoding means perform encoding that enables the difference value encoded signal and the pixel number encoded signal to be uniquely identified. An image encoding device characterized by performing the following. 37. The image encoding apparatus according to claim 36, wherein the prediction error encoding unit and the pixel number encoding unit determine the predetermined value to be compared with the changed pixel difference value by using the predetermined value of the scanning line. An image coding apparatus, wherein the setting is performed using the number of pixels. 38. An image encoding apparatus which receives a two-dimensional shape signal representing a region where a pixel representing an object is present, and encodes the shape signal, wherein the object is represented from the input shape signal. Significant region extracting means for extracting a significant region which is a rectangular region including pixels, and outputting a significant region range which is a range of the extracted significant region, and dividing the shape signal into blocks each including a plurality of pixels. Means, for each block output by the blocking means, determine whether or not to include the significant area, if it is determined to include the significant area, encode at least the significant area of the block, shape An image coding apparatus, comprising: shape coding means for outputting a coded signal, wherein the significant region range and the shape coded signal are used as coded signals. 39. The image encoding device according to claim 38, wherein the shape encoding means extracts a minimum rectangular area including the significant area from each block formed by the blocking means, An image encoding apparatus for encoding only the inside of the extracted rectangular area. 40. An image encoding apparatus for encoding a two-dimensional image signal by inputting a two-dimensional image signal composed of a plurality of pixels, comprising: separating the image signal into at least two image signals;
An image signal separating unit that outputs the separated image signal as two or more partial image signals; and selects at least one of the partial image signals as a target partial image signal, and encodes the selected target partial image signal. A first image signal encoding unit that outputs a first encoded signal; and a target image signal among the partial image signals, based on an image signal obtained by decoding the first encoded signal. Predicting the excluded non-target partial image signal, calculating the probability that the prediction hits, and outputting the calculated prediction probability, according to the prediction probability calculated by the prediction probability calculation means, A second image signal encoding unit that determines a decoding priority and encodes the non-target partial image signal by using an encoding method according to the determined priority path. Image sign Apparatus. 41. The image encoding apparatus according to claim 40, wherein the second image signal encoding unit is configured to perform the decoding priority so that a pixel having a small prediction probability is preferentially decoded. An image encoding apparatus characterized in that: 42. The image coding apparatus according to claim 40, wherein the prediction probability calculating means increases the hit probability when the neighboring pixel values are the same, and sets the neighboring pixel values to different values. In the case of (1), the probability of hitting is reduced. 43. An image decoding apparatus for inputting and decoding an encoded signal, comprising decoding the encoded signal to obtain an encoding mode and a difference value, A decoding unit that outputs the obtained difference value as a decoding difference value, with the mode as a mode signal, and a coded and decoded pixel in the frame, based on a pixel whose pixel value changes, the input signal of the input signal. First predicting means for predicting a changed pixel and outputting the predicted pixel as a first predicted pixel; and motion compensation based on a pixel having a changed pixel value among coded and decoded pixels in the reference frame. A second prediction unit that predicts a change pixel of the input signal and outputs the predicted pixel as a second prediction pixel; and when the mode signal indicates the frame prediction, Adding the decoding difference value to the prediction pixel of the above, and when the mode signal indicates reference frame prediction, adding means for adding the decoding difference value to the second prediction pixel. An image decoding apparatus characterized in that the pixel is a changed pixel. 44. An image decoding apparatus for inputting and decoding an encoded signal, wherein the image decoding apparatus decodes the encoded signal to acquire an encoding mode and a difference value, and A decoding unit that outputs the obtained difference value as a decoding difference value with the mode as a mode signal, and a pixel whose pixel value of the coded and decoded pixel changes by scanning the image signal in the horizontal direction. A first predicting unit that predicts a change pixel of the input signal based on the image signal and outputs the predicted pixel as a first predicted pixel; and encoding and decoding by scanning the image signal in the vertical direction. A second prediction unit that predicts a changed pixel of the input signal based on a pixel having a changed pixel value of the converted pixel, and outputs the predicted pixel as a second predicted pixel; When indicating the prediction of the directional scanning, the decoding difference value is added to the first prediction pixel. When the mode signal indicates the prediction of the vertical scanning, the decoding difference value is added to the second prediction pixel. An image decoding apparatus comprising: an adding unit for adding, wherein an output of the adding unit is a changed pixel. 45. An image decoding apparatus for inputting and decoding an encoded signal, wherein the image decoding apparatus decodes the encoded signal to obtain a difference value and a pixel value of a changed pixel. A decoding unit that outputs the pixel value of the acquired changed pixel as a decoded pixel value, using the difference value as a decoded difference value; and, based on the pixel whose pixel value of the decoded pixel changes,
A prediction unit that predicts a changed pixel of the input coded signal and outputs the predicted pixel as a predicted pixel; adds the decoded difference value and the predicted pixel; and outputs a result of the addition as a corrected difference value An image decoding apparatus comprising: an adding unit that performs a decoding process on a multi-valued image signal based on the corrected difference value and the decoded pixel value. 46. An image decoding apparatus for receiving an encoded signal and decoding the encoded signal, comprising: decoding a difference value of a pixel value signal from the encoded signal, and outputting the decoded value as a decoded pixel value difference value. Decoding means, a second decoding means for decoding a difference value of a transparency signal from the coded signal, and outputting as a decoded transparency difference value; a motion vector of a pixel value signal from the coded signal; Third decoding means for decoding the motion vector of the degree signal and outputting a decoded pixel value motion vector and a decoded transparency degree motion vector, and a pixel value signal of a reference image described later using the decoded pixel value motion vector. A first motion compensating unit that outputs a result of the motion compensation as a compensated pixel value signal, adds the decoded pixel value difference value and the compensated pixel value signal, and decodes the result of the addition. Pixel value First addition means for outputting as a pixel value signal of the reference image while outputting as a reference signal, and a motion compensation result of a transparency signal of the reference image described later using the decoded transparency motion vector, A second motion compensating means for outputting a decoded transmittance difference value and a compensated transmittance signal, outputting the sum as a decoded transmittance signal, and a reference image An image decoding apparatus, comprising: a second adding unit that outputs the signal as a transparency signal. 47. The image decoding apparatus according to claim 46, wherein said third decoding means decodes a motion vector of the pixel value signal and a difference value of the motion vector to decode the motion vector of the pixel value signal and the decoded pixel value motion vector. An image decoding apparatus comprising: obtaining a motion vector difference value; adding the decoded pixel value motion vector and the decoded motion vector difference value to obtain the decoded transparency motion vector.