JP2008219628A - Motion compensation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motion compensation apparatus which improves image quality of a decoded image. <P>SOLUTION: A decoder 11 inputs a stream encoded by a predetermined standard and outputs a decoded image. A motion vector is included in the stream. A high-precision motion compensation section 12 inputs a high-precision vector, performs motion compensation on an outputted frame and outputs a motion compensated image. A selection section 13 compares, for each region, the decoded image outputted from the decoder 11 with the motion compensated image which is motion-compensated by the high-precision motion compensation section 12, and selects out an image with higher image quality for each region. A frame memory 14 stores an output image and outputs a stored frame to the high-precision motion compensation section 12. Thus, motion compensation is performed on next and following frames in the high-precision motion compensation section 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motion compensation device that improves the image quality of a decoded image.

  Currently, in digital broadcasting, MPEG-2 and AVC / H. The H.264 system is widely used. In digital broadcasting, in order to ensure decoder compatibility and reduce costs, operational rules are provided that further limit the parameters allowed in the coding standard.

  In order to continue the service for the popular decoders, it is rare for broadcasting to expand the encoding method and the operating rules. On the other hand, since the performance of devices constituting the decoder is improved year by year, a device that incorporates a decoder or a decoding function that will be developed later has a high computing capability. For this reason, a decoder developed after the encoding method and operation rules are determined can perform more complex image processing than the operations defined in the encoding rules and operation rules.

  As the accuracy of the motion vector used in the motion compensation processing in image compression encoding increases, the image quality of the encoded image improves. However, the use of highly accurate motion vectors improves the amount of computation of the encoder and decoder. The accuracy of the motion vector is determined according to the progress of the device, and the newer encoding standard has higher accuracy. For example, MPEG-1 and MPEG2 use a motion vector with an accuracy of 0.5 pixels, MPEG-4 uses a motion vector with an accuracy of 0.5 to 0.25 pixels, and MPEG-4 AVC / H. H.264 uses motion vectors with an accuracy of 0.25 pixels. In this specification, “accuracy” of a motion vector means “unit” or “step” instead of “accuracy”.

In the encoder currently used, a larger amount of code is assigned to the I frame than the P frame and the B frame. Therefore, the image quality of the I frame is higher than the image quality of the P frame and the B frame.
Impress standard textbook series revised edition H.264 / AVC textbook (ISBN 4-8443-2204-4), pages 20-21, page 48 Impress

  In an image where the camera is panning or an image where the subject is moving, there are many areas where the moving speed does not match the accuracy of the motion vector of the coding standard. In such a region, motion compensation prediction is performed using a motion vector slightly different from the original motion of the object.

  An image in which panning of 0.25 pixels is performed for each frame is encoded with a motion compensation accuracy of 0.5 pixels (the first frame is encoded as an I frame and the subsequent frame is encoded as a P frame) FIG. 15 shows an example of encoding with the IPPP structure.

  The decoded image 2 is obtained by encoding the original image 1 with the first frame as an I frame and decoding it. From the second frame (P frame), a predicted image 3 obtained by motion-compensating the decoded image 2 with an accuracy of 0.5 pixels and a decoded image 6 obtained by compressing the difference image 5 between the predicted image 3 and the original image 4 are obtained. It is done. Here, although the original image 4 moves 0.25 pixels with respect to the previous frame, the predicted image 3 is the decoded image 2 of the previous frame due to the limitation of the encoding method. Are moved with an accuracy of 0.5 pixels, that is, 0 pixels are moved or 0.5 pixels are moved by the block. For this reason, there is an error of 0.25 pixel shift between the predicted image 3 and the original image 4, and such an error causes the quality of the decoded image 6 to deteriorate.

  In the third frame, a predicted image 7 obtained by motion compensation of the decoded image 6 with 0.5 pixel accuracy and a difference image 9 between the predicted image 7 and the original image 8 are obtained. Similarly, since the predicted image 7 is motion-compensated by a motion vector different from the original motion, the predicted image 7 not only has an error of 0.25 pixel shift from the original image 8, but also Since the decoded image 6 whose image quality has already been reduced is used as a base, the error between the predicted image 7 and the original image 8 becomes a large value, and the image quality of the decoded image 10 further decreases.

  As described above, when motion compensation with accuracy lower than the original motion vector is performed, the motion compensation prediction error of each frame becomes large, which causes image degradation. Furthermore, when there is not a sufficient bit rate for transmitting the prediction error, deterioration accumulates for each frame.

  An object of the present invention is to provide a motion compensation device that improves the image quality of a decoded image.

A first motion compensation apparatus according to the present invention includes:
A decoding unit that receives the stream including the first motion vector, encoded according to a predetermined standard, and generates a decoded image;
A second motion vector having a higher accuracy than the first motion vector is input, and compensation means for motion-compensating an image using the second motion vector to generate a motion-compensated image;
Generating means for generating an output image based on the decoded image and the motion compensated image;
And storing means for storing the output image and outputting the stored output image to the compensation means.

The second motion compensation apparatus according to the present invention is:
A decoding unit that receives the stream including the first motion vector, encoded according to a predetermined standard, and generates a decoded image;
A second motion vector having a higher accuracy than the first motion vector is input, and compensation means for motion-compensating an image using the second motion vector to generate a motion-compensated image;
Generating means for generating an output image based on the decoded image and the motion compensated image,
The decoding means comprises:
It has an accumulation means for accumulating the output image and outputting the accumulated output image to the compensation means.

The third motion compensation apparatus according to the present invention is:
A decoding unit that receives the stream including the first motion vector, encoded according to a predetermined standard, and generates a decoded image;
A second motion vector having a higher accuracy than the first motion vector is input, and compensation means for motion-compensating an image using the second motion vector to generate a motion-compensated image;
Generating means for generating an output image based on the decoded image and the motion compensated image;
The decoded image and the output image are stored, and storage means for outputting one of the stored decoded image and output image to the compensation unit is provided.

A fourth motion compensation apparatus according to the present invention includes:
In the first to third motion compensation apparatuses according to the present invention, the first motion vector and a difference vector between the first motion vector and the second motion vector are input, and the first motion vector An addition means for adding the difference vector to generate the second motion vector and outputting the second motion vector to the compensation means is further provided.

A fifth motion compensation apparatus according to the present invention includes:
Encoding means for encoding an input image into a stream including a first motion vector encoded according to a predetermined standard, and outputting the stream to a decoder;
Detecting means for detecting a second motion vector with higher accuracy than the first motion vector between the already output image and the input image;
Compensation means for generating a motion compensated image by motion-compensating an image using the second motion vector while the second motion vector is input;
Generating means for generating an output image based on the image obtained by decoding the stream and the motion compensated image;
And storing means for accumulating the output image and outputting the accumulated output image to the detecting means and the compensating means.

A sixth motion compensation apparatus according to the present invention includes:
Encoding means for encoding an input image into a stream including a first motion vector encoded according to a predetermined standard, and outputting the stream to a decoder;
Detecting means for detecting a second motion vector with higher accuracy than the first motion vector between the already output image and the input image;
Compensation means for generating a motion compensated image by motion-compensating an image using the second motion vector while the second motion vector is input;
Generating means for generating an output image based on the image obtained by decoding the stream and the motion compensated image,
The encoding means is
It has an accumulating means for accumulating the output image and outputting the accumulated output image to the motion vector detecting means and the compensating means.

A seventh motion compensation apparatus according to the present invention includes:
Encoding means for encoding an input image into a stream encoded with a predetermined standard and including a first motion vector, and outputting the stream to a decoder;
Detecting means for detecting a second motion vector with higher accuracy than the first motion vector between the already output image and the input image;
Compensation means for generating a motion compensated image by motion-compensating an image using the second motion vector while the second motion vector is input;
Generating means for generating an output image based on the image obtained by decoding the stream and the motion compensated image;
And storing an image obtained by decoding the stream and the output image, and storing means for outputting one of the stored decoded image and output image to the detection unit and the compensation unit. .

An eighth motion compensation apparatus according to the present invention includes:
The first motion vector and the second motion vector are input, and the first motion vector and the second motion vector are subtracted from the first motion vector by subtracting the second motion vector. Further, subtracting means for generating a difference vector is provided.

  According to the present invention, since motion compensation of an image is performed using a second motion vector with higher accuracy than the first motion vector, motion compensation can be performed using a motion vector that matches the original motion of the image. As a result, the image quality of the decoded image can be improved.

Embodiments of a motion compensation apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram of a first embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment applied to digital broadcasting or the like includes a decoder 11, a high-precision motion compensation unit 12, a selection unit 13, and a frame memory 14.

  The decoder 11 is a conventional decoder to which an encoding method such as MPEG-2 is applied, and receives a stream encoded according to a predetermined standard such as an encoding standard or an operation rule, and outputs a decoded image. The stream includes a motion vector. The high-precision motion compensation unit 12 receives a vector with higher accuracy than the motion vector included in the stream (hereinafter referred to as “high-precision vector”), and compensates the already output frame for motion compensation and outputs a motion compensated image. To do. In the present embodiment, high-precision motion compensation is performed by dividing an image into blocks each having the same size as the block size used in the encoding scheme to be applied, and the accuracy of the motion vector included in the stream and the accuracy of the high-precision vector Is a combination of 0.5 pixels and 0.25 pixels.

  The selection unit 13 compares the decoded image output from the decoder 11 with the motion compensated image motion-compensated by the high-precision motion compensation unit 12 for each region, and selects and outputs the higher image quality for each region. . The frame memory 14 accumulates the output image and outputs the accumulated frame to the high-precision motion compensation unit 12. As a result, the high-precision motion compensation unit 12 performs motion compensation in the subsequent frames.

  The operation of this embodiment will be described with reference to FIG. According to the present embodiment, in order to improve the image quality of only the motion compensation frame, the decoded image 2 output from the decoder 11 is output as the first frame. The decoded image 2 is stored in the frame memory 14.

  In the second frame, the high-precision motion compensation unit 12 generates a motion compensated image 15 in which the decoded image 2 is motion-compensated with a high-precision vector with an accuracy of 0.25. The selection unit 13 compares the motion compensated image 15 and the decoded image 3 output by the decoder for each region, selects the higher image quality for each region, and outputs the output image 16. Here, the motion compensated image 15 is an image that has been motion compensated by the same motion vector as the motion of the original image 4, and thus is very similar to the original image 4. Therefore, the selection unit 13 outputs the motion compensated image 15 for most areas in the screen. The output image 16 is accumulated in the frame memory 14 and used for motion compensation in the subsequent frames.

  In the conventional decoder, the image quality deteriorates due to an error generated as a result of motion compensation with a motion vector different from the original motion. However, according to the present embodiment, a high-precision vector, that is, a motion vector with higher accuracy than the encoding standard By using, high image quality (of I frames) can be maintained. In addition, since a conventional stream encoded according to a predetermined standard such as an encoding standard or operation regulations is used, it can be decoded by a conventional decoder.

  In addition to the stream, the only information to be input to the motion compensation apparatus according to the above embodiment is a high-precision motion vector, so that the image quality of the decoded image can be improved by increasing the bit rate lower than that of the stream.

  FIG. 3 is a block diagram of a second embodiment of the motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment applied to digital broadcasting or the like includes an encoder 21, a high-precision motion vector detection unit 22, a high-precision motion compensation unit 23, a selection unit 24, and a frame memory 25. .

  The encoder 21 is a conventional encoder to which an encoding method such as MPEG-2 is applied, encodes an input image into a stream, and outputs the stream to the decoder 11 in FIG. The high-precision vector detection unit 22 detects a high-precision motion vector between the output of the frame memory 25 and the input image. The high-precision motion compensation unit 23 receives the high-precision vector from the high-precision vector detection unit 22, and performs motion compensation on the output of the frame memory 25 to output a motion compensated image.

  The selection unit 24 compares the input image and the motion compensated image motion-compensated by the high-precision motion compensation unit 23 for each region, selects the higher image quality for each region, and outputs the output image to the frame memory 25 To do. The frame memory 25 accumulates output images and outputs the accumulated frames to the high-precision motion vector detection unit 22 and the high-precision motion compensation unit 23.

  According to the present embodiment, it is possible to generate a stream and a high-precision motion vector that are input to the motion compensation apparatus of the first embodiment.

  FIG. 4 is a block diagram of a third embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment includes a decoder 31, a high-precision motion compensation unit 32, and a selection unit 33.

  In the present embodiment, the decoder 31 has a frame memory (not shown) that accumulates the decoded image output from the decoder 31. Such a frame memory includes MPEG-2, AVC / H. The decoder of the encoding standard using motion compensation prediction such as H.264 system originally has. The frame memory outputs the accumulated frames to the high-precision motion compensation unit 32. According to the present embodiment, the image quality of the decoded image is improved without having an additional frame memory, which is advantageous when resources are limited.

  FIG. 5 is a block diagram of a fourth embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus of the present embodiment that generates a stream and a high-precision motion vector input to the motion compensation apparatus of the third embodiment includes an encoder 41, a high-precision motion vector detection unit 42, and a high-precision motion. A compensation unit 43 and a selection unit 44 are provided.

  In the present embodiment, the encoder 41 has a frame memory (not shown) that stores the encoded image output from the encoder 41. Such a frame memory includes MPEG-2, AVC / H. The decoder of the encoding standard using motion compensation prediction such as H.264 system originally has. This frame memory outputs the accumulated frames to the high-precision motion compensation unit 12. According to the present embodiment, a stream and a high-precision motion vector are generated without an additional frame memory, which is advantageous when resources are limited.

  FIG. 6 is a block diagram of a fifth embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment includes a decoder 51, a high-precision motion compensation unit 52, a selection unit 53, and a frame memory 54.

  In the present embodiment, both the decoded image output from the decoder 51 and the output image output from the selection unit 53 are input to the frame memory 54, and the image that obtains a higher quality result is the high-precision motion compensation unit. 52 is input.

  FIG. 7 is a block diagram of a sixth embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment for generating a stream and a high-precision motion vector input to the motion compensation apparatus according to the fifth embodiment includes an encoder 61, a high-precision motion vector detection unit 62, and a high-precision motion. Compensation unit 63, selection unit 64, and frame memory 65 are provided.

  In the present embodiment, both the encoded image output from the encoder 61 and the output image output from the selection unit 64 are input to the frame memory 65, and the image with the higher image quality result is detected with high accuracy vector detection. Is input to the unit 62 and the high-precision motion compensation unit 63.

  FIG. 8 is a block diagram of a seventh embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment includes a decoder 71, an adder 72, a high-precision motion compensation unit 73, a selection unit 74, and a frame memory 75.

  The decoder 71 is a conventional decoder based on a general coding scheme that performs orthogonal transform and motion compensation, and includes an entropy decoding unit 71a, an inverse quantization / inverse transform unit 71b, a motion compensation unit 71c, and an adder 71d. And a frame memory 71e.

  Since the decoder 71 is a conventional decoder, only the decoding method of the P frame will be described in the present embodiment. The entropy decoding unit 71a entropy-decodes the stream, outputs the quantized orthogonal transform coefficient to the inverse quantization / inverse transform unit 71b, and outputs the motion vector to the motion compensation unit 71c and the adder 72.

  The inverse quantization / inverse transform unit 71b performs inverse quantization and inverse transform on the quantized orthogonal transform coefficient, and the output is added to the output of the motion compensation unit 71c in the adder 71d, and the sum of these outputs is added. Becomes the decoded image of the decoder 71. The decoded image is stored in the frame memory 71e and used for motion compensation of the next frame. The motion compensation unit 71c performs motion compensation on the past frame image output from the decoder 71 output from the frame memory 71e using a motion vector, and outputs a motion compensated image.

  In the present embodiment, the adder 72 adds a motion vector and a high-precision difference vector made up of the difference between the motion vector and the high-precision motion vector to generate a high-precision motion vector. The high precision motion compensation unit 73 outputs a motion compensated image in which the output of the frame memory 75 is motion compensated with the high precision motion vector output from the adder 72. The selection unit 74 receives selection information that is information indicating which of the decoded image output from the decoder 71 and the motion compensated image motion-compensated by the high-precision motion compensation unit 73 is selected, and based on the received selection information. Thus, the decoded image output from the decoder 71 and the motion compensated image motion-compensated by the high-precision motion compensation unit 73 are selected and output for each region.

  According to the present embodiment, the information to be received by the motion compensation device other than the stream is only the difference from the high-precision motion vector and the selection signal, so that an increase in the bit rate can be suppressed. Also, the transmission bit rate of the high-precision motion vector can be reduced by adding the high-precision vector and the high-precision difference vector to generate a high-precision motion vector.

  FIG. 9 is a block diagram of an eighth embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment includes an encoder 81, a frame memory 82, a high-precision motion vector detection unit 83, a high-precision motion compensation unit 84, a subtractor 85, and a selection information generation unit 86. .

  The encoder 81 is a conventional encoder based on a general encoding method that performs direct transform and motion compensation, encodes an input image into a stream, and outputs the stream to the entropy decoding unit 71a of the decoder 71 in FIG. For this purpose, the encoder 81 includes a motion vector detection unit 81a, a motion compensation unit 81b, a subtractor 81c, a transform / quantization unit 81d, an inverse quantization / inverse transform unit 81e, an adder 81f, a frame A memory 81g and an entropy encoding unit 81h are included.

  The high-precision motion vector detection unit 83 detects a high-precision motion vector between the output of the frame memory 82 and the input image. The high-precision motion compensation unit 84 performs motion compensation on the output of the frame memory 82 using the high-precision motion vector detected by the high-precision motion vector detection unit 83, and generates a motion compensated image. The selection information generation unit 86 compares the local decoded output of the encoder 81 and the motion compensated image output from the high-precision motion compensation unit 84 with the input image, and outputs the selection information input to the selection unit 74 of FIG. The selection result image is output to the frame memory 82. It should be noted that a general moving image encoder such as MPEG-2 performs figure local decoding by itself. The high-precision difference vector and the selection information are collectively entropy-encoded and transmitted at the subsequent stage.

  The subtracter 85 obtains a difference (high accuracy difference vector) between the encoder motion vector output from the encoder 81 and the high accuracy motion vector, and outputs the high accuracy difference vector input to the adder 72 in FIG. . By transmitting the high-precision difference vector in this way, the transmission bit rate of the high-precision motion vector can be reduced.

  According to the present embodiment, it is possible to generate a stream high-precision difference vector and selection information that are input to the motion compensation device according to the seventh embodiment.

  FIG. 10 is a block diagram of a ninth embodiment of the motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment includes a decoder 91, an adder 92, a high-precision motion compensation unit 93, and a selection unit 94.

  The decoder 91 is a conventional decoder based on a general coding scheme that performs direct transform and motion compensation, and includes an entropy decoding unit 91a, an inverse quantization / inverse transform unit 91b, a motion compensation unit 91c, and an adder 91d. And a frame memory 91e.

  In the present embodiment, the frame memory 91e stores the decoded image output from the adder 91d and outputs the stored frame to the high-precision motion compensation unit 32. According to the present embodiment, the image quality of the decoded image is improved without having an additional frame memory, which is advantageous when resources are limited.

  FIG. 11 is a block diagram of a tenth embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment for generating a stream, a high-precision difference vector, and selection information input to the motion compensation apparatus according to the ninth embodiment includes an encoder 101, a high-precision motion vector detection unit 102, A high-precision motion compensation unit 103, a subtracter 104, and a selection information generation unit 105 are provided.

  The encoder 101 is a conventional encoder based on a general coding method that performs orthogonal transform and motion compensation, and includes a motion vector detection unit 101a, a motion compensation unit 101b, a subtractor 101c, a transform / quantization unit 101d, , An inverse quantization / inverse transform unit 101e, an adder 101f, a frame memory 101g, and an entropy encoding unit 101h.

  In the present embodiment, the frame memory 101g accumulates the decoded image output from the adder 101f and outputs the accumulated frame to the high-precision motion compensation unit 103. According to the present embodiment, the image quality of the decoded image is improved without having an additional frame memory, which is advantageous when resources are limited.

  FIG. 12 is a graph of an output image obtained by the present invention and an output image obtained by a conventional decoder. In FIG. 12, the horizontal axis represents the bit rate and the vertical axis represents PSNR. The output of the motion compensator according to the present invention is represented by a solid line, and the output of a conventional decoder is represented by a broken line.

  The graph shown in FIG. 12 is a result measured by the motion compensator shown in FIG. 10 and FIG. 11, and the output of the motion compensator according to the present invention shown by the solid line corresponds to the output of the selection unit 94 and is shown by the broken line in the related art. The decoder output corresponds to the output of the inverse quantization / inverse transform unit 91b.

  The used image is a pan image having a width of 320 pixels and a height of 240 lines. As an encoding method, an H.264 image having a motion vector accuracy of 0.5 pixels is used. 263, and 0.25 pixel was used as the accuracy of the high-precision motion vector of the present invention. The bit rate is H.264 for the output of the conventional decoder. The bit rate of the H.263 stream is used. In addition to the H.263 stream, a high-precision difference vector and the bit rate of the selection information are added.

  As shown in FIG. 10, it can be seen that the output of the motion compensator according to the present invention has higher image quality than the conventional decoder, and therefore the image quality of the output image can be improved by slightly increasing the bit rate.

  FIG. 13 is a block diagram of an eleventh embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment includes a decoder 111, an adder 112, a high-precision motion compensation unit 113, a selection unit 114, and a frame memory 115.

  The decoder 111 is a conventional decoder based on a general coding scheme that performs direct transform and motion compensation, and includes an entropy decoding unit 111a, an inverse quantization / inverse transform unit 111b, a motion compensation unit 111c, and an adder 111d. And a frame memory 111e.

  In the present embodiment, the selection information includes two types of information: selection of an image output from the frame memory 115 and selection of an image output from the selection unit 114. Both the decoded image output from the frame memory 111e and the output image output from the selection unit 114 are input to the frame memory 115, and an image selected based on selection information including information on which image to output is selected. Input to the high-precision motion compensation unit 113.

  FIG. 14 is a block diagram of a twelfth embodiment of a motion compensation apparatus according to the present invention. The motion compensation apparatus according to the present embodiment for generating a stream, a high-precision difference vector, and selection information input to the motion compensation apparatus according to the eleventh embodiment includes an encoder 121, a frame memory 122, and a high-precision motion vector. A detection unit 123, a high-precision motion compensation unit 124, a subtractor 125, and a selection information generation unit 126 are provided.

  The encoder 121 is a conventional encoder based on a general coding scheme that performs orthogonal transform and motion compensation, and includes a motion vector detection unit 121a, a motion compensation unit 121b, a subtractor 121c, a transform / quantization unit 121d, , An inverse quantization / inverse transform unit 121e, an adder 121f, a frame memory 121g, and an entropy encoding unit 121h.

  In the present embodiment, both the decoded image output from the frame memory 121g and the output image output from the selection information generation unit 126 are input to the frame memory 122, and the image with the higher image quality is obtained with higher accuracy. Input to the motion compensation unit 124. A signal indicating which image is selected is sent to the selection information property western 126 and output as a part of the selection information.

The present invention is not limited to the above-described embodiment, and many changes and modifications can be made.
For example, in the above embodiment, either one of the decoded image and the motion compensated image is used as the output image, but a composite image of the decoded image and the motion compensated image can be used instead of the motion compensated image. . In addition, the case where the combination of the accuracy of the motion vector included in the stream and the accuracy of the high-precision vector is 0.5 pixel and 0.25 pixel has been described. A combination of these can also be used.

  In addition, the encoder and the decoder can be arbitrarily configured according to the encoding scheme to be applied. In the above embodiment, the case where high-precision motion compensation is performed by dividing an image for each block having the same size as the block size used in the applied encoding method has been described. The transmission bit rate of the high-precision difference vector and selection information can be reduced by using a block size larger than the block size, and high-precision motion compensation can be achieved by using a block size smaller than the block size used in the applied coding scheme. The image quality can also be improved.

  Further, the transmission bit rate of the high-precision difference vector and the selection information can be lowered by performing compression processing on the transmission bit rate of the high-precision difference vector and the selection information. When receiving information subjected to such compression processing, an expansion unit for the information subjected to compression processing is provided in the input unit.

  Further, when the selection information can be estimated from other information such as a high-precision difference vector, reception of the selection information can be omitted. For example, when the high-precision difference vector is 0 in both the horizontal direction and the vertical direction, if the decoder output is used, the selection unit can select without receiving selection information. Further, transmission of high-precision difference vectors that are not selected can be omitted.

  Further, a delay circuit can be provided in the signal path to synchronize signals, and weighting can be performed in the selection unit.

1 is a block diagram of a first embodiment of a motion compensation apparatus according to the present invention. FIG. It is a figure for demonstrating the image decoding by this invention. It is a block diagram of 2nd Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 3rd Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 4th Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 5th Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 6th Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 7th Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 8th Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 9th Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 10th Embodiment of the motion compensation apparatus by this invention. It is the graph of the output image obtained by this invention, and the output image obtained by the conventional decoder. It is a block diagram of 11th Embodiment of the motion compensation apparatus by this invention. It is a block diagram of 12th Embodiment of the motion compensation apparatus by this invention. It is a figure for demonstrating the conventional image decoding.

Explanation of symbols

1, 4, 8 Original image 2, 3, 7 Predicted image 5, 9 Difference image 6, 10 Decoded image 15 Motion compensated image 16 Output image 11, 31, 51, 61, 91, 111 Decoder 12, 23, 32, 43 , 52, 63, 73, 84, 93, 103, 113, 124 High-precision motion compensation unit 13, 24, 33, 44, 53, 64, 74, 94, 114 Selection unit 14, 25, 54, 65, 71e, 75, 81g, 82, 91e, 101g, 111e, 115, 121g, 122 Frame memory 21, 41, 61, 81, 101, 121 Encoder 22, 42, 62, 83, 102, 123 High-precision motion vector detection unit 71a, 91a, 111a Entropy decoders 71b, 81e, 91b, 101e, 111b, 121e Inverse quantization / inverse transform units 71c, 81b, 91 c, 101b, 111c, 121b Motion compensation unit 71d, 72, 81f, 91d, 92, 101f, 111d, 112, 121f Adder 81a, 101a, 121a Motion vector detection unit 81c, 85, 101c, 104, 121c, 125 Subtraction 81d, 101d, 121d Transformer / quantizer 81h, 101h, 121h Entropy encoder 86, 105, 126 Selection information generator

Claims (8)

A decoding unit that receives the stream including the first motion vector, encoded according to a predetermined standard, and generates a decoded image;
A second motion vector having a higher accuracy than the first motion vector is input, and compensation means for motion-compensating an image using the second motion vector to generate a motion-compensated image;
Generating means for generating an output image based on the decoded image and the motion compensated image;
A motion compensation apparatus comprising: accumulation means for accumulating the output image and outputting the accumulated output image to the compensation means. A decoding unit that receives the stream including the first motion vector, encoded according to a predetermined standard, and generates a decoded image;
A second motion vector having a higher accuracy than the first motion vector is input, and compensation means for motion-compensating an image using the second motion vector to generate a motion-compensated image;
Generating means for generating an output image based on the decoded image and the motion compensated image,
The decoding means comprises:
A motion compensation apparatus comprising: an accumulation unit that accumulates the output image and outputs the accumulated output image to the compensation unit. A decoding unit that receives the stream including the first motion vector, encoded according to a predetermined standard, and generates a decoded image;
A second motion vector having a higher accuracy than the first motion vector is input, and compensation means for motion-compensating an image using the second motion vector to generate a motion-compensated image;
Generating means for generating an output image based on the decoded image and the motion compensated image;
A motion compensation apparatus comprising: an accumulation unit that accumulates the decoded image and the output image, and outputs one of the accumulated decoded image and the output image to the compensation unit.   The first motion vector and a difference vector between the first motion vector and the second motion vector are input, and the second motion is obtained by adding the first motion vector and the difference vector. 4. The motion compensation apparatus according to claim 1, further comprising addition means for generating a vector and outputting the second motion vector to the compensation means. 5. Encoding means for encoding an input image into a stream including a first motion vector encoded according to a predetermined standard, and outputting the stream to a decoder;
Detecting means for detecting a second motion vector with higher accuracy than the first motion vector between the already output image and the input image;
Compensation means for generating a motion compensated image by motion-compensating an image using the second motion vector while the second motion vector is input;
Generating means for generating an output image based on the image obtained by decoding the stream and the motion compensated image;
A motion compensation apparatus comprising: an accumulation means for accumulating the output image and outputting the accumulated output image to the detection means and the compensation means. Encoding means for encoding an input image into a stream including a first motion vector encoded according to a predetermined standard, and outputting the stream to a decoder;
Detecting means for detecting a second motion vector with higher accuracy than the first motion vector between the already output image and the input image;
Compensation means for generating a motion compensated image by motion-compensating an image using the second motion vector while the second motion vector is input;
Generating means for generating an output image based on the image obtained by decoding the stream and the motion compensated image,
The encoding means is
A motion compensation apparatus, comprising: an accumulation unit that accumulates the output image and outputs the accumulated output image to the motion vector detection unit and the compensation unit. Encoding means for encoding an input image into a stream encoded with a predetermined standard and including a first motion vector, and outputting the stream to a decoder;
Detecting means for detecting a second motion vector with higher accuracy than the first motion vector between the already output image and the input image;
Compensation means for generating a motion compensated image by motion-compensating an image using the second motion vector while the second motion vector is input;
Generating means for generating an output image based on the image obtained by decoding the stream and the motion compensated image;
And storing an image obtained by decoding the stream and the output image, and storing means for outputting one of the stored decoded image and output image to the detection unit and the compensation unit. Motion compensation device.   The first motion vector and the second motion vector are input, and the first motion vector and the second motion vector are subtracted from the first motion vector by subtracting the second motion vector. The motion compensation apparatus according to claim 5, further comprising subtracting means for generating a difference vector between

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