JP5238735B2 - Signal correction apparatus, encoding apparatus, decoding apparatus, and program - Google Patents

Description

  The present invention relates to an image processing technique, and more particularly to a signal correction device, an encoding device, a decoding device, and a program for correcting an image signal that has been encoded by an irreversible encoding method and has undergone encoding degradation.

  As a signal interpolation technique using the correlation between component signals constituting an image signal, a technique for improving the accuracy of a pixel interpolation method in a single-plate primary color image sensor has been reported (for example, see Non-Patent Document 1). Since the image signal interpolation technique in such an image sensor is intended to interpolate RGB signals (R: red signal, G: green signal, B: blue signal) in the RGB color space, signal deterioration due to encoding is assumed. It has not been.

  Further, as a signal interpolation technique focusing on the difference in sampling frequency of YUV signals in the YUV color space, a color difference component interpolation technique for format color images has been reported (for example, see Non-Patent Document 2). In this technique, high-precision interpolation is performed by generating an interpolated signal of a color difference signal (U signal = BY, V signal = RY) using the sampling frequency of the luminance (Y) signal. . The signal interpolation technique that pays attention to such a difference in the sampling frequency of the YUV signal is also intended for the interpolation of the YUV signal, so that signal degradation due to encoding is not assumed.

  These signal interpolation techniques are suitable for interpolation on an image signal before encoding when encoding an image signal by an irreversible encoding method (for example, MPEG-2, H.264, etc.). It is not suitable for interpolation on the image signal after conversion. For example, when a YUV signal is encoded by irreversible encoding processing, the deterioration of the luminance signal propagates to the color difference signal based on the luminance signal as the luminance signal deteriorates. In addition, these signal interpolation techniques are not processes for reducing the degradation of the luminance signal itself, and therefore do not reduce the degradation of the luminance signal.

  In addition, there are various deblocking filters (for example, deblocking filters in H.264 etc.) in order to reduce the degradation of encoding, but these deblocking filters visually degrade each of the image signal components. Are processed independently so as not to stand out, and deterioration after encoding of the original image signal cannot be reduced.

Kuno, Sugiura, “Higher accuracy of pixel interpolation in single-plate primary color image sensor”, Journal of the Institute of Image Information and Television Engineers, Vol. 61, no. 7. July 1, 2007, pp. 1006 to 1016 Sugita, Taguchi, "YUV4: 2: 0 format color difference component interpolation method", IEICE Transactions, Vol. J88-A, no. 6, June 1, 2005, pp. 751-760

  In the conventional signal interpolation technique that pays attention to the difference in sampling frequency of the YUV signal in the YUV color space, signal interpolation is performed based on the signal deterioration caused at the time of encoding. Therefore, the effect of reducing deterioration of the YUV signal before encoding is reduced. It does not play.

  Even if the component signals representing the same area of the decoded image are compared and corrected, the correction is not necessarily correct for the YUV signal before encoding.

  In view of the above-described problems, an object of the present invention is to provide a signal correction device, an encoding device, a decoding device, and a program that can correct a YUV signal before encoding.

  The signal correction apparatus according to the present invention compares signal degradation caused during encoding between component signals representing the same region of a decoded image (hereinafter, typically described with respect to a YUV signal), and performs encoding. Based on the previous YUV signal (hereinafter referred to as “reference YUV signal”), the signal element of the component signal (for example, the pixel value of the block or the orthogonal transformation coefficient) to be corrected is determined, and the signal element of the component signal is corrected. It is configured to generate flag information indicating a location and / or a normalization parameter indicating a correction amount of a signal element of a component signal, and transmit the flag information and / or normalization parameter separately from the corrected YUV signal. The The component signal may be in any color space such as RGB, YCrCb, LUV, Lab, XYZ.

In other words, the signal correction apparatus according to the first aspect of the present invention is a signal correction apparatus for correcting a component signal of a moving image including a signal element of a pixel value or an orthogonal transformation coefficient, and is obtained through an irreversible encoding method. A first component signal (for example, a luminance signal) of a decoded signal (a corrected YUV signal described later) in an image signal of a predetermined image format is input and normalized, and the normalized first component signal is Teacher signal generating means for generating a teacher signal of a second component signal (for example, a color difference signal) having a sampling frequency different from that of the first component signal of the decoded signal, and the second of the decoded signals. and component signals, while comparing the signal elements of the same area with the teacher signal input from the teacher signal generating means, said Based on the second component signal of the reference image signal of the predetermined image format before being encoded by the encoding method, it determines the correction location of the signal element that should correct the signal degradation that has occurred during encoding. Te, a correction judging means for generating flag information indicating the corrected portion of the signal components to be corrected, with respect to the second component signal of said decoded signal, in accordance with the flag information, the signal element to be the modified Correction processing means for correcting the signal with the signal element of the teacher signal and generating a corrected second component signal.

  In the signal correction device according to the first aspect of the present invention, the teacher signal generation means normalizes the first component signal (for example, a luminance signal) based on the AC energy of the second component signal. And a teacher signal of the second component signal is generated.

In the signal correction device according to the first aspect of the present invention, the teacher signal generation means includes means for inputting the reference image signal (reference YUV signal described later) , and a first component signal ( For example, the luminance signal) is normalized based on the AC energy of the second component signal (for example, color difference signal) in the reference signal, and the teacher signal of the second component signal in the decoded signal is obtained. It is characterized by generating.

  Further, in the signal correction device according to the first aspect of the present invention, the flag information represents a correction point in signal element units or divided block units for the signal elements of each component signal.

  Further, in the signal correction device according to the first aspect of the present invention, the teacher signal generation unit is configured to perform processing between the second component signal of the decoded signal and the teacher signal input from the teacher signal generation unit. Means for comparing signal elements and generating a normalization parameter representing a correction amount of the signal element to be corrected.

  Furthermore, the signal modification device of the first aspect can be configured by a computer.

Furthermore, the signal correction device according to the second aspect of the present invention is a signal correction device for correcting a component signal of a moving image including a signal element of a pixel value or an orthogonal transform coefficient, and is obtained through an irreversible encoding method. A first component signal (for example, a luminance signal) of a decoded signal (a corrected YUV signal described later) in an image signal of a predetermined image format is input and normalized, and the normalized first component signal is Teacher signal generating means for generating a teacher signal of a second component signal (for example, a color difference signal) having a sampling frequency different from that of the first component signal of the decoded signal, and the second of the decoded signals. and component signals, while comparing the signal elements of the same area between the teacher signal, prior to encoding by the encoding scheme Serial generated based on the second component signal of the reference image signal of a predetermined image format, type the flag information representing the corrected portion of the signal components to be corrected signal degradation that occurred during encoding, For the second component signal of the decoded signal, the signal element to be corrected is corrected with the signal element of the teacher signal in accordance with the flag information, and a corrected second component signal is generated. Correction processing means.

  In the signal correction device according to the second aspect of the present invention, the teacher signal generation means normalizes the first component signal (for example, a luminance signal) based on the AC energy of the second component signal. And a teacher signal of the second component signal is generated.

  Further, in the signal correction device according to the second aspect of the present invention, the teacher signal generation means (between the second component signal of the decoded signals and the teacher signal input from the teacher signal generation means) A means for inputting a normalization parameter representing a correction amount of the signal element to be corrected (generated by comparing the signal elements in step), and a first component signal (for example, a luminance signal) of the decoded signal Based on the normalization parameter, a teacher signal of the second component signal of the decoded signal is generated.

  Furthermore, the signal correction device of the second aspect can be configured by a computer.

  According to the present invention, since the YUV signal is corrected based on the YUV signal before encoding, the image deterioration can be further reduced as compared with the case where the present invention is not applied.

It is a block diagram of the encoding side signal correction apparatus of one Example by this invention. It is a block diagram of the encoding side signal correction apparatus of one Example by this invention. It is a figure which shows the structural example which corrects a to-be-corrected YUV signal by replacement | exchange of an orthogonal transformation coefficient as a signal element of a component signal in the encoding side signal correction apparatus of one Example by this invention. (A) shows how the U and V signals of the color difference signal in the 4: 2: 0 format are corrected using the down-converted luminance signal Y, and (b) shows the luminance in the 4: 2: 0 format. It is a figure which shows a mode that the signal Y is corrected using the U signal or V signal of an up-converted color difference signal. (A) shows how the U and V signals of the color difference signal in the 4: 2: 2 format are corrected using the down-converted luminance signal Y, and (b) shows the luminance in the 4: 2: 2 format. It is a figure which shows a mode that the signal Y is corrected using the U signal or V signal of an up-converted color difference signal. It is the schematic of the encoding apparatus to which the encoding side signal correction apparatus of one Example by this invention is applied. It is a block diagram of the decoding side signal correction apparatus of one Example by this invention. It is a block diagram of the decoding side signal correction apparatus of one Example by this invention. It is a figure which shows the structural example which corrects a to-be-corrected YUV signal by replacement | exchange of an orthogonal transformation coefficient as a signal element of a component signal in the decoding side signal correction apparatus of one Example by this invention. It is the schematic of the decoding apparatus to which the decoding side signal correction apparatus of one Example by this invention is applied. It is an operation | movement flow of the encoding side signal correction apparatus of one Example by this invention. It is an operation | movement flow of the decoding side signal correction apparatus of one Example by this invention. (A) is a figure which shows the example which corrects the signal element of a component signal per signal element, (b) is a figure which shows the example which corrects in the unit of the block divided | segmented about the signal element of the component signal. It is a figure which illustrates the relationship between the luminance signal and color difference signal in a to-be-corrected YUV signal, and the YUV signal after correction. It is a block diagram of the encoding side signal correction apparatus of the modification by this invention. (A) is a figure which shows the example of a signal of 4: 2: 2 format in a frame image, (b) is a figure which shows the example of a signal of 4: 2: 0 format in a frame image.

  A signal correction apparatus according to an embodiment of the present invention will be described below.

  First, in order to understand the present invention, a general image format used in image coding will be described. In general, in image encoding, one image frame is composed of a combination of signals of different pixel sizes because of differences in sensitivity to luminance and color differences in human perception. As such an image format, as shown in FIG. 16 (a), for the pixel S1 in the frame image F, the 4: 2: 2 format (in the horizontal direction, the number U of pixels of the luminance signal (Y) is 1). As shown in FIG. 16B, the number of pixels of the signal and the V signal is 1/2), and the pixel S2 in the frame image F has a 4: 2: 0 format (luminance signal in the horizontal and vertical directions). The number of pixels of each of the U signal and the V signal is ½) with respect to the number of pixels 1.

  In a typical block coding such as MPEG, such an image signal is coded for every certain number of pixels without distinguishing between a luminance signal and a color difference signal. For this reason, the image ranges occupied by the encoding blocks of the luminance signal and the color difference signal are different, and the range in which the encoding deterioration occurs is also different.

  The difference in the number of samplings expressed by the luminance signal and the color difference signal means that the sampling frequency of the luminance signal and the color difference signal is different. For example, in the case of 4: 2: 2 format, two color difference signals (U signal and V signal) corresponding to an image range formed by luminance signals of 16 × 16 pixels are each configured by 8 × 16 pixels. Therefore, in the case of the 4: 2: 2 format, the sampling frequency of the color difference signal is halved with respect to the luminance signal in the horizontal direction. Similarly, in the 4: 2: 0 format, the sampling frequency of the color difference signal is halved with respect to the luminance signal in the horizontal and vertical directions.

  In the following description, typically, based on the reference YUV signal (reference color difference signal), the signal element of the color difference signal (U signal / V signal) in the corrected YUV signal is represented in the corrected YUV signal. An example in which a corrected YUV signal (corrected color difference signal) is obtained by correcting with a signal element of a teacher signal generated from the luminance signal (Y signal) will be described.

  From the relationship between the component signals shown in FIG. 16, the luminance signal (Y signal) of the corrected YUV signal and the corrected YUV signal of the corrected YUV signal are based on the reference YUV signal (reference luminance signal). The signal component of the luminance signal (Y signal) in the corrected YUV signal is compared with the color difference signal (U signal / V signal) and the signal component of the color difference signal (U signal / V signal) in the corrected YUV signal. It is also possible to obtain a corrected YUV signal (corrected luminance signal) by correcting with elements. Therefore, both the luminance signal and the color difference signal can be corrected from each other from the correlation between the luminance signal and the color difference signal.

  In the following description, an example in which the YUV signal includes a luminance signal and a color difference signal having different sampling frequencies as illustrated in FIG. 16 will be described. The reference YUV signal may be considered as a YUV signal before encoding, and the corrected YUV signal may be considered as a decoded signal of the encoded YUV signal.

  FIG. 1 is a block diagram of an encoding-side signal modification device 10 according to an embodiment of the present invention. The encoding-side signal correction device 10 includes a teacher signal generation unit 11, a correction determination unit 12, and a correction processing unit 13.

  The encoding-side signal correction device 10 inputs a corrected YUV signal of a predetermined image format that is output from a decoder (not shown) that decodes an image signal encoded by, for example, an irreversible encoding method. Using the YUV signal, a new YUV signal (corrected luminance signal and color difference signal) according to the predetermined image format is generated while suppressing encoding deterioration of the luminance signal and color difference signal.

  That is, the teacher signal generation unit 11 receives and normalizes the luminance signal of the corrected YUV signal, generates a normalized luminance signal as a teacher signal of the color difference signal, and sends it to the correction determination unit 12 and the correction processing unit 13. Send it out. In the normalization process of the luminance signal in the corrected YUV signal here, for example, linear conversion is performed so that the AC energy is matched with the color difference signal (U signal and / or V signal) in the corrected YUV signal. To generate.

  The correction determination unit 12 receives a color difference signal from the YUV signal to be corrected and inputs a signal element (for example, a pixel value or orthogonal transform coefficient in the block) between the teacher signal input from the teacher signal generation unit 11. ) Is generated, flag information indicating the correction portion (coordinates) of the signal element to be corrected for the color difference signal in the corrected YUV signal is generated and sent to the outside of the encoding-side signal correction device 10 and corrected. The data is sent to the processing unit 13. In this comparison processing, since the signal element of the reference YUV signal is the original correct signal, in this case, based on the signal element of the color difference signal in the reference YUV signal, the teacher is instructed about the color difference signal in the corrected YUV signal. The correction part (coordinate) of the signal element to be corrected is specified by correcting (for example, replacing) with the signal element of the signal.

  The correction processing unit 13 receives the color difference signal of the corrected YUV signal, and corrects the signal element to be corrected for the color difference signal of the corrected YUV signal according to the flag information input from the correction determination unit 12. The location (coordinates) is corrected (for example, replaced) with the signal element of the teacher signal, and a YUV signal including the corrected color difference signal is transmitted to the outside.

  As a result, on the receiving side that receives the signal from the encoding-side signal correction device 10, when receiving the YUV signal including the corrected color difference signal, which signal of which signal is relative to the signal element of the reference YUV signal. It is possible to know from the flag information whether the element has been modified.

  FIG. 2 is a block diagram of the encoding-side signal modification device 20 according to an embodiment of the present invention. Components similar to those in FIG. 1 are described with the same reference numerals. The encoding side signal correction device 20 is the same as that of FIG. 1 in that it includes a teacher signal generation unit 11, a correction determination unit 12, and a correction processing unit 13. When the signal generation unit 11 receives and normalizes the luminance signal of the corrected YUV signal and generates the normalized luminance signal as the teacher signal of the color difference signal, the signal generation unit 11 corresponds to the signal element of the teacher signal of the color difference signal. The difference is that a normalization parameter representing a correction amount generated by the difference between the signal elements of the color difference signal in the reference YUV signal to be generated is generated and sent to the outside of the encoding-side signal correction device 10. Also, the teacher signal of the encoding-side signal correction device 20 shown in FIG. 2 is the same as the teacher signal of the encoding-side signal correction device 10 shown in FIG. In contrast to the signal generated by, for example, linear conversion so as to match the AC energy with the V signal), the AC signal is changed with respect to the color difference signal (U signal and / or V signal) in the reference YUV signal. For example, it is generated by linear transformation so as to match the energy. The correction amount caused by the difference between the two signal elements can be a linear conversion parameter as the simplest example.

  For example, when approximating the signal element (Y) of the teacher signal of the chrominance signal with the signal element (X) of the chrominance signal in the corresponding reference YUV signal, when using an approximation function of Y = aX + b, the normalization parameters a and b Can be obtained.

  Therefore, the encoding-side signal correction device 20 receives the color difference signal of the corrected YUV signal by the correction processing unit 13 and includes the corrected YUV signal according to the flag information input from the correction determination unit 12. When the YUV signal including the corrected color difference signal is transmitted to the outside by correcting (for example, replacing) the correction portion (coordinates) of the signal element to be corrected with respect to the color difference signal with the signal element of the teacher signal. The determination unit 12 and the teacher signal generation unit 11 send out flag information indicating the correction location of the signal element of the component signal generated based on the reference YUV signal and the normalization parameter indicating the correction amount of the signal element of the component signal, respectively. .

  As a result, the receiving side that receives the signal from the encoding-side signal correction device 20 knows which signal element of which signal has been corrected by the flag information when receiving the YUV signal including the corrected color difference signal. It is possible to know with the normalization parameter how much correction amount is added to the corrected signal element to approach the signal element of the reference YUV signal.

  Therefore, a more specific example will be described below based on the most preferable configuration of the encoding-side signal correction device 20.

  FIG. 3 shows an example of correcting the corrected YUV signal by replacing the orthogonal transformation coefficient as the signal element of the component signal with respect to the encoding-side signal correction device 20. As will be described with reference to FIG. 2, the teacher signal generation unit 11 includes a sampling rate conversion unit 11a, a third orthogonal conversion unit 11b, and a normalization processing unit 11c. The correction determination unit 12 includes a second orthogonal transform unit 12a and a comparison unit 12b. The correction processing unit 13 includes a first orthogonal transform unit 13a, an orthogonal transform coefficient replacement unit 13b, and an inverse orthogonal transform unit 13c.

  In the case of this example, the sampling rate conversion unit 11a down-converts the luminance signal of the corrected YUV signal to the sampling rate of the corresponding color difference signal and sends it to the third orthogonal conversion unit 11b. When correcting the luminance signal of the corrected YUV signal, the sampling rate converter 11a up-converts the color difference signal of the corrected YUV signal to the sampling rate of the corresponding luminance signal and performs the third orthogonal operation. The data is sent to the conversion unit 11b.

  As described above, the pixel block (8 × 8 pixels) of one luminance signal and the pixel block (8 × 8 pixels) of one color difference signal, which are the minimum units of the encoding process, are sampled for the luminance signal and the color difference signal. The image range expressed from the difference is different. Deterioration due to quantization differs for each pixel block of 8 × 8 pixels, and the tendency of deterioration of each block is uncorrelated, so that visually noticeable deterioration may occur particularly at the boundary between pixel blocks.

  However, considering that the area of the color difference signal after encoding is twice as large as the area of the luminance signal after encoding (or horizontal and vertical), the corresponding luminance is calculated from the color difference signal. It is possible to know the correlation of signals between adjacent pixel blocks of the signal. Also, since the number of luminance signal samplings is higher than that of chrominance signals and has a higher resolution, the luminance signal including coding degradation is down-converted to the sampling rate of the chrominance signal to reduce the degradation, and this luminance is reduced. The color difference signal can be restored by using the signal as a teacher signal for the color difference signal. Therefore, in order to compare the correlation between the luminance signal and the color difference signal, it is preferable that the sampling rates of the luminance signal and the color difference signal are the same.

  When correcting the luminance signal of the corrected YUV signal, the sampling rate conversion unit 11a converts one or both of the two color difference signals in the corrected YUV signal. Predefined.

  In the case of this example, the third orthogonal transform unit 11b performs orthogonal transform similar to the orthogonal transform process used in the first orthogonal transform unit 13a on the down-converted luminance signal input from the sampling rate transform unit 11a. The obtained orthogonal conversion coefficient of the down-converted luminance signal is sent to the normalization processing unit 11c.

  The second orthogonal transform unit 12a performs orthogonal transform similar to the orthogonal transform process used in the first orthogonal transform unit 13a on the color difference signal of the input reference YUV signal, and orthogonal transform of the obtained color difference signal The coefficient is sent to the normalization processing unit 11c and the comparison unit 12b.

  The normalization processing unit 11c receives the orthogonal transformation coefficient of the down-converted luminance signal from the third orthogonal transformation unit 11b, and exchanges AC with each value of the orthogonal transformation coefficient of the color difference signal of the reference YUV signal that is input separately from this. The orthogonal transformation coefficient of the luminance signal is normalized by adjusting (for example, linear transformation) so as to match the energy, and the orthogonal transformation coefficient of the normalized luminance signal is generated as a teacher signal of the color difference signal, and the comparison unit 12b and the orthogonal transformation coefficient The data is sent to the replacement unit 13b. Further, when the normalization processing unit 11c generates the orthogonal transform coefficient of the normalized luminance signal as the teacher signal of the color difference signal, the signal element of the teacher signal of the color difference signal and the signal of the color difference signal in the corresponding reference YUV signal A normalization parameter representing a correction amount caused by the difference between the elements is generated and transmitted to the outside of the encoding-side signal correction device 20.

  In the case of this example, the first orthogonal transform unit 13a performs a predetermined orthogonal transform process (for example, DCT) on the color difference signal in the input corrected YUV signal, and performs orthogonal transform of the obtained color difference signal. The coefficients are sent to the orthogonal transform coefficient replacement unit 13b and the comparison unit 12b.

  The comparison unit 12b receives the orthogonal transformation coefficient of the color difference signal in the corrected YUV signal from the first orthogonal transformation unit 13a, and the orthogonal transformation coefficient of the teacher signal input from the normalization processing unit 11c. The signal element (orthogonal transform coefficient in this example) is compared, and flag information representing the correction portion (coordinates) of the signal element to be corrected for the color difference signal in the corrected YUV signal is generated to correct the encoding side signal. The data is sent to the outside of the device 20 and sent to the orthogonal transform coefficient replacement unit 13b. In this comparison processing, since the signal element of the reference YUV signal input to the comparison unit 12b is the original correct signal, in this case, based on the signal element of the color difference signal in the reference YUV signal, the corrected YUV signal Among these, the correction part (coordinates) of the signal element to be corrected by the signal element of the teacher signal is specified.

  The orthogonal transform coefficient replacing unit 13b receives the orthogonal transform coefficient of the color difference signal in the corrected YUV signal from the first orthogonal transform unit 13a, and the corrected YUV signal of the corrected YUV signal according to the flag information input from the comparison unit 12b. The correction part (coordinates) of the orthogonal transformation coefficient to be corrected for the color difference signal is corrected (for example, replaced) with the orthogonal transformation coefficient of the teacher signal, and the orthogonal transformation coefficient of the corrected color difference signal is converted to the inverse orthogonal transformation unit 13c. To send.

  The inverse orthogonal transform unit 13c performs inverse orthogonal transform (for example, IDCT) on the orthogonal transform coefficient of the corrected color difference signal input from the orthogonal transform coefficient replacement unit 13b, and sends it to the outside. The above describes the case of correcting the color difference signal from the luminance signal, but the same applies to the case of correcting the color difference signal from the luminance signal.

  4 and 5 are diagrams schematically showing a series of processing operations in the encoding-side signal correction device 20. FIG. 4A shows how the U signal and V signal of the color difference signal in the 4: 2: 0 format are corrected using the down-converted luminance signal Y, and FIG. 4B shows the 4: It shows how the luminance signal Y in the 2: 0 format is corrected using the U signal or V signal of the up-converted color difference signal. FIG. 5A shows how the U signal and V signal of the color difference signal in the 4: 2: 2 format are corrected using the down-converted luminance signal Y, and FIG. It shows how the luminance signal Y in the 2: 2 format is corrected using the U signal or V signal of the up-converted color difference signal.

  As a result, according to the encoding-side signal correction device 20 of the present embodiment, even an image signal (corrected YUV signal) that has been decoded through an irreversible encoding method is decoded based on the reference YUV signal. Therefore, it can be corrected as an image signal with little image deterioration (YUV signal after correction), and image deterioration caused by encoding can be further reduced.

  Note that MPEG-2 and MPEG-4 AVC / H. Although DCT is used as orthogonal transform in many encoding systems such as H.264, according to the signal correction apparatus of this embodiment, the difference in the sampling frequency of the luminance signal of the image signal and the color difference signal that are generally used is used. Can be applied to any coding scheme. In particular, when an image deteriorated by an irreversible encoding method is input and the purpose is to recover the deterioration due to the encoding method, the same orthogonal transformation as the encoding method used for input is used. Thus, the effect of reducing deterioration will be exhibited.

  Hereinafter, a case where the encoding side signal correction device 20 of the present embodiment is applied to a moving image encoding device will be described.

[Encoding device]
In general, a moving image is encoded by motion compensation prediction, orthogonal transform, quantization, and variable length encoding. In the case of an encoding method using motion compensated prediction, a decoding device is included in an encoding device in order to use a decoded image for prediction, and the signal correction device of this embodiment is applied to the output of the decoding device. can do.

  FIG. 6 shows an example in which the encoding side signal correction device 20 of this embodiment is applied to a moving image encoding device 60. In the following description, the same components will be described with the same reference numerals.

  The encoding device 60 includes an encoding-side signal correction device 20, a rearrangement unit 112, a subtraction unit 113, an orthogonal transformation unit 114, a quantization unit 115, a variable length encoding unit 116, An inverse quantization unit 117, an inverse orthogonal transform unit 118, a frame memory 121, a motion compensation prediction unit 122, and an addition unit 123 are provided. The encoding device 60 according to the present embodiment is different from the known encoding device (for example, the encoding device for MPEG-2, H.264) in that the encoding-side signal correction device 20 according to the present embodiment is the same. It has been added. Note that the encoding-side signal correction device 20 of the present embodiment can be provided for so-called intra prediction and motion compensation prediction, but an example in which motion compensation prediction is performed will be typically described.

  The rearrangement unit 112 rearranges image signals (for example, image sensor output) configured as an array of pixel values for each pixel as a frame image, and subtracts the input image signal constituting the frame image from the subtraction unit 113 and motion compensation. Send to the prediction unit 122.

  The motion compensation prediction unit 122 performs motion vector detection on the input image signal supplied from the rearrangement unit 112 using a reference image acquired from the frame memory 121 via the encoding side signal correction device 20, and is obtained. The motion compensation is performed using the obtained motion vector, and the predicted image obtained as a result is output to the subtraction unit 113 and the addition unit 123. The motion vector information is sent to the variable length encoding unit 16.

  The subtraction unit 113 generates a difference signal between the input image signal from the rearrangement unit 112 and the predicted image from the motion compensation prediction unit 122 and sends the difference signal to the orthogonal transformation unit 114.

  The orthogonal transform unit 114 performs orthogonal transform (for example, DCT) on the differential signal supplied from the subtraction unit 113 for each pixel block in the small region, and sends the result to the quantization unit 115.

  The quantization unit 115 selects a quantization table corresponding to the pixel block in the small area supplied from the orthogonal transform unit 114, performs quantization processing, and sends the quantization table to the variable length coding unit 116 and the inverse quantization unit 117. .

  The variable length encoding unit 116 performs variable length encoding processing on the quantized signal supplied from the quantization unit 115 to generate a bitstream, and information on the motion vector supplied from the motion compensation prediction unit 122 is also variable length. Encode and output.

  The inverse quantization unit 117 performs inverse quantization processing on the quantized signal supplied from the quantization unit 115 and outputs the result to the inverse orthogonal transform unit 118.

  The inverse orthogonal transform unit 118 performs inverse orthogonal transform (for example, IDCT) on the orthogonal transform coefficient supplied from the inverse quantization unit 117 and outputs the result to the addition unit 123.

  The adding unit 123 adds the signal obtained by the inverse orthogonal transform obtained from the inverse orthogonal transform unit 118 and the prediction image obtained from the motion compensated prediction unit 122 to generate a decoded image, and stores the decoded image in the frame memory 121.

  Here, the encoding-side signal correction device 20 in FIG. 6 can acquire the corrected YUV signal from the frame memory 121 and can acquire the reference YUV signal from the rearrangement unit 112. 6 performs the above-described correction process on the YUV signal to be corrected based on the reference YUV signal, and sends the flag information (and the normalization parameter) to the variable length encoding unit 116. . The variable length coding unit 116 may perform coding on the flag information and the normalization parameter, or may perform transmission without performing coding.

  In this way, by applying the encoding-side signal correction devices 10 and 20 in the encoding device 60, the corrected YUV signal is compared with the teacher signal based on the reference YUV signal, and among the corrected YUV signals, By correcting the signal element of the component signal with the signal element of the teacher signal generated from the component signal different from the component signal, it is possible to obtain a corrected YUV signal that is more approximate to the original signal.

  Next, the decoding side signal correction devices 70 and 80 for correcting the corrected YUV signal using the flag information (and the normalization parameter) will be described in order.

  In the following description, based on the flag information (and normalization parameter), typically, the signal element of the color difference signal (U signal / V signal) in the corrected YUV signal is represented by the luminance in the corrected YUV signal. An example of obtaining a corrected YUV signal (corrected color difference signal) by correcting with a signal element of a teacher signal generated from a signal (Y signal) will be described. An example in which the YUV signal is composed of a luminance signal and a color difference signal having different sampling frequencies as shown in FIG. 16 will be described.

  From the relationship between the component signals shown in FIG. 16, the luminance signal (Y signal) in the corrected YUV signal is converted into the corrected YUV signal based on the input flag information (and the normalization parameter). By correcting the color difference signal (U signal / V signal), a corrected YUV signal (corrected luminance signal) can be obtained. Therefore, both the luminance signal and the color difference signal can be corrected from each other from the correlation between the luminance signal and the color difference signal.

  First, the decoding side signal correction device 70 shown in FIG. 7 is a device corresponding to the decoding side signal correction device 10 shown in FIG. 1, and includes a teacher signal generation unit 71 and a correction processing unit 72. The correction processing unit 72 operates in the same manner as the correction processing unit 13 on the encoding side, inputs the corrected YUV signal, and based on the input flag information, the signal element of a certain component signal of the corrected YUV signal Is modified (for example, replaced) with the signal element of the teacher signal obtained from the teacher signal generation unit 71 to generate a corrected YUV signal. The teacher signal generation unit 71 normalizes a signal element of a component signal different from the component signal of the YUV signal to be corrected, and sends it to the correction processing unit 72 as a teacher signal. Since the decoding-side signal correction device 70 shown in FIG. 7 corrects the component signal of the reference YUV signal using the flag information as the coordinate information of the signal element to be corrected, Maintain accuracy. However, the teacher signal generated by the teacher signal generation unit 71 shown in FIG. 7 is a component signal component other than the component signal of the corrected YUV signal, and the component of the corrected YUV signal is the same as in FIG. Since it is generated by normalization using a signal (for example, linear conversion so that AC energy is matched), even if the correction location is accurate, from the viewpoint of the correction amount, there is an error with respect to the component signal of the reference YUV signal Can occur.

  8 is an apparatus corresponding to the encoding-side signal correction apparatus 20 shown in FIG. 2, and serves as a teacher signal generation unit 71 that inputs a normalization parameter and generates a teacher signal. Composed.

  That is, the correction processing unit 72 of the decoding-side signal correction device 80 shown in FIG. 8 is the same operation as the correction processing unit 72 shown in FIG. 7, and receives the corrected YUV signal and based on the input flag information. Then, the signal element of a certain component signal of the YUV signal to be corrected is corrected (for example, replaced) with the signal element of the teacher signal obtained from the teacher signal generation unit 71, and the corrected YUV signal is generated. On the other hand, the teacher signal generation unit 71 of the decoding-side signal correction device 80 shown in FIG. 8 normalizes a signal element of a component signal different from the component signal of the YUV signal to be corrected using a normalization parameter, and It is different from that shown in FIG. 7 in that it is sent to the correction processing unit 72 as a signal. That is, the teacher signal generation unit 71 of the decoding-side signal correction device 80 shown in FIG. 8 corresponds to the reference YUV signal for the signal element of the component signal different from the component signal of the YUV signal to be corrected, as in FIG. The teacher signal is generated by normalization using a normalization parameter that can be corrected (for example, linear transformation to match AC energy). As a result, the decoding-side signal correction device 80 shown in FIG. 8 maintains accuracy with respect to the correction location and the correction amount of the signal element.

  Therefore, a more specific example will be described below based on the most preferable configuration of the decoding-side signal correction device 80.

  FIG. 9 shows an example of correcting the corrected YUV signal by replacing the orthogonal transform coefficient as the signal element of the component signal in the decoding-side signal correction device 80. As will be described in comparison with FIG. 8, the teacher signal generation unit 71 includes a sampling rate conversion unit 71a, a second orthogonal conversion unit 71b, and a normalization processing unit 71c. The correction processing unit 72 includes a first orthogonal transform unit 72a, an orthogonal transform coefficient replacement unit 72b, and an inverse orthogonal transform unit 72c.

  In the case of this example, the sampling rate conversion unit 71a down-converts the luminance signal of the corrected YUV signal to the sampling rate of the corresponding color difference signal and sends it to the second orthogonal conversion unit 71b. When correcting the luminance signal of the corrected YUV signal, the sampling rate conversion unit 71a up-converts the color difference signal of the corrected YUV signal to the sampling rate of the corresponding luminance signal and performs the second orthogonal operation. The data is sent to the conversion unit 71b.

  When correcting the luminance signal in the corrected YUV signal, the sampling rate conversion unit 71a converts one or both of the two color difference signals in the corrected YUV signal. It is preferable to preliminarily prescribe and prescribe it to be the same on the encoding side and the decoding side.

  In the case of this example, the second orthogonal transform unit 71b performs orthogonal transform similar to the orthogonal transform process used in the first orthogonal transform unit 72a on the down-converted luminance signal input from the sampling rate conversion unit 71a. The obtained orthogonal transform coefficient of the down-converted luminance signal is sent to the normalization processing unit 71c. It is preferable that the encoding side and the decoding side are defined to have the same orthogonal transform type.

  The normalization processing unit 71c receives the orthogonal transformation coefficient of the luminance signal after down-conversion from the second orthogonal transformation unit 71b, and the orthogonal transformation coefficient of the color difference signal of the reference YUV signal according to a normalization parameter input separately from this. By adjusting (for example, linear conversion) so that AC energy is matched to each value of, the orthogonal transformation coefficient of the luminance signal is normalized, and the orthogonal transformation coefficient of the normalized luminance signal is generated as a teacher signal of the color difference signal, and orthogonal transformation is performed. It is sent to the coefficient replacement unit 72b. Further, the normalization parameter includes a signal element of the color difference signal teacher signal and a signal element of the color difference signal in the corresponding reference YUV signal when generating the orthogonal transform coefficient of the normalized luminance signal as the color difference signal teacher signal. 2 is obtained from the encoding-side signal correction device 20 shown in FIG.

  In the case of this example, the first orthogonal transform unit 72a performs a predetermined orthogonal transform process (for example, DCT) on the color difference signal in the input corrected YUV signal, and performs orthogonal transform of the obtained color difference signal. The coefficients are sent to the orthogonal transform coefficient replacement unit 72b.

  The orthogonal transform coefficient replacing unit 72b receives the orthogonal transform coefficient of the color difference signal in the corrected YUV signal from the first orthogonal transform unit 72a, and the color difference in the corrected YUV signal according to separately input flag information. The correction part (coordinates) of the orthogonal transformation coefficient to be corrected for the signal is corrected (for example, replaced) with the orthogonal transformation coefficient of the teacher signal obtained from the normalization processing unit 71c, and the orthogonal transformation coefficient of the corrected color difference signal Is sent to the inverse orthogonal transform unit 72c.

  The inverse orthogonal transform unit 72c performs inverse orthogonal transform (for example, IDCT) on the orthogonal transform coefficient of the corrected color difference signal input from the orthogonal transform coefficient replacement unit 72b, and transmits the result to the outside. The above describes the case of correcting the color difference signal from the luminance signal, but the same applies to the case of correcting the color difference signal from the luminance signal.

  Hereinafter, the case where the decoding side signal correction device 80 of the present embodiment is applied to a moving image decoding device will be described.

[Decoding device]
An example in which the decoding-side signal correction device 80 of the present embodiment is applied to a moving image decoding device 90 is shown in FIG. In the following description, the same components will be described with the same reference numerals.

  The decoding device 90 according to the present embodiment includes a variable length decoding unit 132, an inverse quantization unit 133, an inverse orthogonal transform unit 134, an addition unit 135, a decoding side signal modification device 80, a frame memory 136, a motion A compensation prediction unit 137 and a rearrangement unit 138 are provided. The decoding device 90 according to this embodiment is obtained by adding the decoding-side signal correction device 80 according to this embodiment to a known decoding device (for example, a decoding device for MPEG-2, H.264). It is.

  The variable-length decoding unit 132 receives the encoded bitstream, performs variable-length decoding processing, sends it to the inverse quantization unit 133, decodes motion vector information, and sends it to the motion compensation prediction unit 137. . Further, the variable length decoding unit 132 sends the flag information and the normalization parameter to the decoding side signal correction device 80.

  The inverse quantization unit 133 obtains an orthogonal transform coefficient of the differential signal that has been subjected to inverse quantization processing on the quantized signal supplied from the variable length decoding unit 132 and motion-compensated, and sends it to the inverse orthogonal transform unit 134. .

  The inverse orthogonal transform unit 134 performs inverse orthogonal transform (for example, IDCT) on the orthogonal transform coefficient of the difference signal supplied from the inverse quantization unit 133, and sends the obtained difference signal to the addition unit 135.

  The motion compensation prediction unit 137 generates a prediction image using the reference image obtained from the frame memory 136 and the motion vector obtained from the variable length decoding unit 132, and outputs the prediction image to the addition unit 135.

  The adding unit 135 adds the difference signal obtained from the inverse orthogonal transform unit 134 and the prediction image supplied from the motion compensation prediction unit 137 to restore the image signal, and the restored image signal is related to the present embodiment. The data is sent to the decoding side signal correction device 80 in the decoding device 90.

  The decoding-side signal correction device 80 in the decoding device 90 generates a corrected image signal that suppresses coding degradation of the image signal obtained from the addition unit 135 as described above, stores the image signal in the frame memory 136, and rearranges the image signal. To the unit 138.

  The rearrangement unit 138 rearranges the corrected image signal obtained from the decoding-side signal correction device 80 as a display signal.

  As described above, the decoding-side signal correction device 80 of this embodiment can be applied to the decoding device 90.

  In the encoding device 60 and the decoding device 90, the signal correction device of the present invention has been incorporated at a specific arrangement position. You can also.

  Hereinafter, operations of the encoding-side signal correction device 20 and the decoding-side signal correction device 80 in the encoding device 60 and the decoding device 90 according to the present embodiment will be described with reference to FIGS. 11 and 12, respectively.

  Referring to FIG. 11, the encoding-side signal correction device 20 receives the reference YUV signal and the corrected YUV signal (step S1).

  The encoding-side signal correction device 20 performs down-conversion of the luminance signal in the corrected YUV signal by the sampling rate converter 11a (step S2), and up-converts the color difference signal in the corrected YUV signal. Execute (Step S3).

  The encoding-side signal correction device 20 performs orthogonal transformation of the luminance signal and the color difference signal in the reference YUV signal by the second orthogonal transformation unit 12a (step S4).

  The encoding-side signal correction device 20 performs orthogonal transformation on each of the luminance signal after down-conversion and the color difference signal after up-conversion by the third orthogonal transformation unit 11b (steps S5 and S6), and normalization processing The unit 11c normalizes each of the orthogonal transform coefficients of the down-converted luminance signal and the up-converted color difference signal based on the color difference signal and the luminance signal orthogonal transform coefficient of the reference YUV signal, respectively. (Steps S7 and S8).

  The encoding-side signal correction device 20 performs a normalization process on each orthogonal transform coefficient of the luminance signal after down-conversion and the color difference signal after up-conversion, so that the color difference signal of the YUV signal to be corrected respectively. In addition, a teacher signal of the luminance signal is generated, and a normalization parameter indicating the correction amount of each signal element (orthogonal transform coefficient) is generated (steps S9, S10, S11).

  The encoding-side signal correction device 20 uses the comparison unit 12b to calculate the orthogonal transform coefficients of the color difference signal and the luminance signal in the corrected YUV signal and the orthogonal transform coefficients of the corresponding teacher signals based on the reference YUV signal. Comparison is made to determine a correction location of the corrected YUV signal (step S12), and information on the correction location is generated as flag information (step S13).

Here, a specific example of flag information will be described. FIG. 13A is a diagram illustrating an example in which the signal elements of the component signal are modified in units of signal elements, and FIG. 13B is a diagram illustrating an example in which the signal elements of the component signal are modified in units of divided blocks. It is. For example, as shown in FIG. 13A, each of the signal elements of the reference YUV signal, the corrected YUV signal, and the teacher signal is composed of 8 × 8 blocks (for example, pixel values or orthogonal transform coefficients). It shall be. For example, whether or not a certain signal element A1 of the corrected YUV signal should be corrected by the signal element A2 at the corresponding coordinate position of the teacher signal is determined by comparing the difference based on the signal element A0 of the reference YUV signal. can do. For example, when (A1-A0) ² > (A2-A0) ² , it is determined that a certain signal element A1 of the YUV signal to be corrected is corrected by the signal element A2 at the corresponding coordinate position of the teacher signal. Similarly for other signal elements, if (B1-B0) ² > (B2-B0) ^2, a signal element B1 of the corrected YUV signal is corrected by the signal element B2 at the corresponding coordinate position of the teacher signal. to decide.

  On the other hand, as shown in FIG. 13B, each of the signal elements of the reference YUV signal, the corrected YUV signal, and the teacher signal is composed of 8 × 8 blocks (for example, pixel values or orthogonal transform coefficients). In this case, for example, the block is divided into four blocks, and a value representing the sum of evaluation values for each signal element in the block can be set as a comparison and replacement target. For example, whether or not a certain signal element (block A1) of the corrected YUV signal should be corrected by the signal element (block A2) at the corresponding coordinate position of the teacher signal is determined based on the signal element (block A0) of the reference YUV signal. Judgment can be made by comparing the magnitude of the difference based on the difference. For example, if the sum of squares of the difference between the signal element of block A0 and the signal element of block A1 is greater than the sum of squares of the difference between the signal element of block A0 and the signal element of block A2, there is a certain corrected YUV signal. It is determined that the signal element (block A1) is corrected by the signal element (block A2) at the corresponding coordinate position of the teacher signal. Similarly, it is determined that other signal element blocks are corrected in units of blocks. By setting the signal element for comparing and replacing the corrected YUV signal as a block unit, the signal amount of flag information can be reduced, and the coding rate can be improved when applied to an encoding apparatus. . The dividing method is not limited to the above-described example, and can be modified in various ways according to individual designs.

  The encoding-side signal correction device 20 uses the orthogonal transformation coefficient replacement unit 13b to use the orthogonal transformation coefficient signal element of each teacher signal and the orthogonal transformation coefficients of the color difference signal and the luminance signal in the YUV signal to be modified. The correction of the correction portion corresponding to the flag information is applied, and the inverse orthogonal transform unit 13c performs inverse orthogonal transform on the orthogonal transform coefficient of the corrected YUV signal (step S14).

  Thus, the encoding-side signal correction device 20 generates the corrected YUV signal, flag information, and normalization parameters. These corrected YUV signals, flag information, and normalization parameters can be used for encoding in the encoding apparatus as described above.

  Referring to FIG. 12, the decoding-side signal correction device 80 inputs flag information and normalization parameters (step S21), and inputs a decoding-side corrected YUV signal (step S22).

  The decoding-side signal correction device 80 performs down-conversion of the luminance signal of the corrected YUV signal by the sampling rate conversion unit 71a (step S23) and up-conversion of the color difference signal of the corrected YUV signal. (Step S24).

  On the other hand, the decoding-side signal correction device 80 performs orthogonal transformation of the luminance signal and the color difference signal in the YUV signal to be modified by the first orthogonal transformation unit 72a (step S25).

  The decoding-side signal correction device 80 performs orthogonal transformation on each of the luminance signal after down-conversion and the color difference signal after up-conversion by the second orthogonal transformation unit 71b (steps S26 and S27), and a normalization processing unit By 71c, each of the orthogonal transform coefficients of the luminance signal after down-conversion and the color difference signal after up-conversion is subjected to normalization processing based on the normalization parameters (steps S28 and S29).

  The decoding-side signal correction device 80 performs normalization processing on each of the orthogonal transform coefficients of the luminance signal after down-conversion and the color difference signal after up-conversion, so that the color difference signal of the YUV signal to be corrected and A teacher signal for the luminance signal is generated (step S30).

  The decoding-side signal correction device 80 uses the orthogonal transform coefficient replacement unit 72b to flag the orthogonal transform coefficients of the color difference signal and the luminance signal in the corrected YUV signal using the signal element of the orthogonal transform coefficient of each teacher signal. The correction of the correction portion corresponding to the information is applied, and the inverse orthogonal transform is performed on the orthogonal transform coefficient of the corrected YUV signal by the inverse orthogonal transform unit 72c (step S31).

  Thus, the decoding-side signal correction device 80 can obtain a corrected YUV signal using the flag information and the normalization parameter. For example, as shown in FIG. 14, the luminance signal and the color difference signal in the corrected YUV signal are corrected for each signal element in consideration of the mutual correlation and the difference with respect to the reference signal, and a corrected YUV signal can be obtained. . The corrected YUV signal is different from the one corrected based only on the correlation between the component signals, and is corrected based on the reference YUV signal. Therefore, the YUV signal is restored as an image signal with little deterioration. Keep in mind that there are.

  Furthermore, as one aspect of the present invention, the encoding-side signal modification devices 10 and 20 or the decoding-side signal modification devices 70 and 80 of each embodiment can be configured as a computer. A program for causing a computer to realize each component of each signal correction device described above is stored in a storage unit provided inside or outside the computer. Such a storage unit can be realized by an external storage device such as an external hard disk or an internal storage device such as ROM or RAM. The control part with which a computer is provided is realizable by control of a central processing unit (CPU). In other words, the CPU can appropriately read from the storage unit a program in which the processing content for realizing the function of each component is described, and realize the function of each component on the computer. Here, the function of each component may be realized by a part of hardware.

  In addition, the program describing the processing contents can be distributed by selling, transferring, or lending a portable recording medium such as a DVD or CD-ROM, and such a program can be distributed on a server on a network, for example. Can be distributed by transferring the program from the server to another computer via the network.

  In addition, a computer that executes such a program can temporarily store, for example, a program recorded on a portable recording medium or a program transferred from a server in its own storage unit. As another embodiment of the program, the computer may directly read the program from a portable recording medium and execute processing according to the program, and each time the program is transferred from the server to the computer. In addition, the processing according to the received program may be executed sequentially.

  While the embodiments of the present invention have been described in detail with specific examples, it will be apparent to those skilled in the art that various modifications and changes can be made without departing from the scope of the claims of the present invention.

  For example, if the sampling rate of the signal input to the signal correction device is the same, the luminance signal down-conversion unit and the color difference signal up-conversion unit can be bypassed.

  Further, the component signals to be corrected by the signal correction device are not limited to inputting YUV signals, respectively. For example, the orthogonal transform coefficient of the YUV signal is changed as in the encoding-side signal correction device 20b shown in FIG. It can also be configured as input. In this case, the first to third orthogonal transform units 13a, 12a, and 11b in the encoding-side signal modification device 20 described above are not necessary, and the sampling rate conversion unit 11d inputs the orthogonal transform coefficient and executes the sampling rate conversion. It will be. Note that a similar modification can be configured for the decoding-side signal correction device.

  Therefore, not only is it configured to compare the component signals in the image signal and / or the signals of these orthogonal transform coefficients, but also to compare the signals that have been input with the component signals and converted in sampling rate. , Compare the orthogonal transform coefficients of the signals whose component signals are input and converted the sampling rate, or compare after quantizing the signals of the orthogonal transform coefficients of each component signal that are input and converted the sampling rate Various modifications are possible such as performing the above-mentioned or using a combination of these.

  According to the present invention, for example, even if an image signal is composed of signal components in color spaces having different sampling frequencies, the image signal can be corrected so as to reduce the deterioration of the image signal. This is useful for any application that uses an image signal that handles encoding processing by a method.

DESCRIPTION OF SYMBOLS 10 Encoding side signal correction apparatus 11 Teacher signal production | generation part 11a Sampling rate conversion part 11b 3rd orthogonal transformation part 11c Normalization process part 11d Sampling rate conversion part 12 Correction judgment part 12a 2nd orthogonal transformation part 12b Comparison part 13 Correction process part 13a First orthogonal transform unit 13b Orthogonal transform coefficient replacement unit 13c Inverse orthogonal transform unit 20 Encoding side signal modification device 60 Encoding device 70 Decoding side signal modification device 71 Teacher signal generation unit 71a Sampling rate conversion unit 71b Second orthogonal transform unit 71c Normalization processing unit 72 Correction processing unit 72a First orthogonal transformation unit 72b Orthogonal transformation coefficient substitution unit 72c Inverse orthogonal transformation unit 80 Decoding side signal modification device 90 Decoding device 112 Rearrangement unit 113 Subtraction unit 114 Orthogonal transformation unit 115 Quantization unit 116 Variable length encoding unit 117 Inverse quantization unit 118 Inverse Converter 121 frame memory 122 motion compensation prediction unit 123 adding unit 132 variable length decoding unit 133 inverse quantization unit 134 inverse orthogonal transform unit 135 adding unit 136 frame memory 137 motion compensation prediction unit 138 sorting unit

Claims (12)

A signal correction device for correcting a component signal of a moving image including a signal element of a pixel value or an orthogonal transform coefficient,
The first component signal of the decoded signal in the image signal of the predetermined image format obtained through the irreversible encoding method is input and normalized, and the normalized first component signal is converted into the decoded signal. Teacher signal generating means for generating a teacher signal of a second component signal having a sampling frequency different from that of the first component signal,
The signal component in the same region is compared between the second component signal of the decoded signal and the teacher signal input from the teacher signal generation unit, and the signal before being encoded by the encoding method Based on the second component signal of the reference image signal of a predetermined image format, the signal element correction part to be corrected is determined by determining the signal element correction part to correct the signal degradation caused at the time of encoding. Correction determination means for generating flag information representing
For the second component signal of the decoded signal, the signal element to be corrected is corrected with the signal element of the teacher signal in accordance with the flag information, and a corrected second component signal is generated. Correction processing means;
A signal correction apparatus comprising:   The teacher signal generation means normalizes the first component signal based on the AC energy of the second component signal to generate a teacher signal of the second component signal. The signal correction device according to claim 1. The teacher signal generation means includes
It means for inputting the reference image signal,
The first component signal of the decoded signal is normalized based on the AC energy of the second component signal in the reference signal, and the teacher signal of the second component signal of the decoded signal is obtained. The signal correction apparatus according to claim 1, wherein the signal correction apparatus generates the signal correction apparatus.   The signal correction device according to any one of claims 1 to 3, wherein the flag information represents a correction portion in a signal element unit or a divided block unit for a signal element of each component signal. .   The teacher signal generation means compares signal elements between the second component signal of the decoded signal and the teacher signal input from the teacher signal generation means, and corrects a signal element to be corrected 5. The signal correction device according to claim 1, further comprising means for generating a normalization parameter representing the quantity.   An encoding apparatus provided with the signal correction apparatus as described in any one of Claims 1-5. A signal correction device for correcting a component signal of a moving image including a signal element of a pixel value or an orthogonal transform coefficient,
The first component signal of the decoded signal in the image signal of the predetermined image format obtained through the irreversible encoding method is input and normalized, and the normalized first component signal is converted into the decoded signal. Teacher signal generating means for generating a teacher signal of a second component signal having a sampling frequency different from that of the first component signal,
The reference image signal of the predetermined image format before comparing the signal components in the same region between the second component signal of the decoded signal and the teacher signal, and before encoding by the encoding method Flag information representing a correction location of a signal element to be corrected for signal degradation generated at the time of encoding generated based on the second component signal of the second component signal is input, and the second of the decoded signals is input Correction processing means for correcting the signal element to be corrected with the signal element of the teacher signal according to the flag information, and generating a corrected second component signal,
A signal correction apparatus comprising:   The teacher signal generation means normalizes the first component signal based on the AC energy of the second component signal to generate a teacher signal of the second component signal. The signal correction device according to claim 7. The teacher signal generation means includes
Means for inputting a normalization parameter representing a correction amount of the signal element to be corrected;
The teacher signal of the second component signal of the decoded signal is generated based on the normalization parameter for the first component signal of the decoded signal. Signal correction device.   A decoding device comprising the signal correction device according to any one of claims 7 to 9. A computer configured as a signal correction device for correcting a component signal of a moving image including a signal element of a pixel value or an orthogonal transform coefficient;
The first component signal of the decoded signal in the image signal of the predetermined image format obtained through the irreversible encoding method is input and normalized, and the normalized first component signal is converted into the decoded signal. Generating a teacher signal of a second component signal having a sampling frequency different from that of the first component signal,
Said second component signal of said decoded signal, as well as comparing the signal elements of the same area with the該教teacher signal, the predetermined image format reference image signal before encoded by the encoding method A step of determining a correction location of a signal element to correct signal degradation caused at the time of encoding based on the second component signal, and generating flag information representing the correction location of the signal element to be corrected When,
For the second component signal of the decoded signal, the signal element to be corrected is corrected with the signal element of the teacher signal in accordance with the flag information, and a corrected second component signal is generated. Steps,
A program for running A computer configured as a signal correction device for correcting a component signal of a moving image including a signal element of a pixel value or an orthogonal transform coefficient;
The first component signal of the decoded signal in the image signal of the predetermined image format obtained through the irreversible encoding method is input and normalized, and the normalized first component signal is converted into the decoded signal. Generating a teacher signal of a second component signal having a sampling frequency different from that of the first component signal,
The reference image signal of the predetermined image format before the signal component of the same region is compared between the second component signal of the decoded signal and the teacher signal, and is encoded by the encoding method Flag information representing a correction location of a signal element to be corrected for signal degradation generated at the time of encoding generated based on the second component signal of the second component signal is input, and the second of the decoded signals is input Correcting the signal element to be corrected with the signal element of the teacher signal in accordance with the flag information, and generating a corrected second component signal,
A program for running

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