Video encoder, video decoder, video encoding method, video decoding method, and video encoding and decoding system

• US 20020118758A1
• Filed: 03/04/2002
• Published: 08/29/2002
• Est. Priority Date: 03/17/1997
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nishikawa, Hirofumi, Asai, Kohtaro, Hasegawa, Yuri, Sekiguchi, Shunichi, Isu, Yoshimi, Murakami, Tokumichi, Kuroda, Shinichi
• Granted Patent: US 7,110,456 B2
• Time in Patent Office: Days
• US Class Current: 375/240.18
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/53 Multi-resolution motion estimation; Hierarchical motion estimation
• CPC Class Codes: H04N 19/537 Motion estimation other than block-based
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

It is an object of the invention to obtain a video encoder and a video decoder performing a highly accurate prediction of a picture, transformed by other than translation, within a short processing time in a small-scaled circuit. A video encoder for performing compression encoding of an input picture includes motion compensated prediction means for performing interframe motion detection. The motion compensated prediction means has a motion detector including a transformed block matching unit for transforming a reference picture portion into a picture portion having a predefined shape for performing motion detection and a motion compensator including a corresponding pel determinator for determining integer pels of real sample points of the transformed reference picture portion corresponding to an integer pel of the input picture block according to the motion parameters supplied from the motion detector as a result of the comparison so as to supply prediction picture data. The video encoder of the present invention can be combined with a video decoder having a motion compensator which performs the same operations as those in the video encoder to configure a video encoding and decoding system. Further, the video decoder uses half-

Claims

1. A video encoder for performing compression encoding of input video divided into predefined blocks, including a motion compensated prediction means for implementing a motion compensation by detecting a motion between frames of blocks of an input video, the video encoder comprising:

a motion detector, including a transformed block matching unit for transforming a reference image portion comprised of only integer pels, which consist of real sampling points, into an image portion having a predefined shape, for determining addresses of pels of a transformed reference image portion, and for matching the transformed reference image portion with the block of input video comprised of integer pels, and the motion detector outputting a motion vector providing a minimum prediction error; and

a motion compensator, including a corresponding pel determinator for transforming the reference image portion based on a motion parameter obtained from a comparison result of the transformed block matching unit, and for determining pels corresponding to pels of the reference image portion, and outputting a prediction image portion.

2. The video encoder according to claim 1, wherein the transformed block matching unit transforms a reference image portion comprised of half-pels as well as integer pels into an image portion having a predefined shape.

3. The video encoder according to claim 1 or 2, further comprising a preprocessor for separating an input video into video objects each of which is an encoding unit, the video encoder dividing the video object into blocks, detecting a motion, and compensating a motion of a divided video object.

4. The video encoder according to claim 1 or 2,

wherein the transformed block matching unit transforms the reference image portion comprised of half-pels as well as integer pels into one of an image portion scaled down at a specific ratio and an image portion scaled up at a specific ratio, determines the addresses of pels of a transformed reference image portion, and matches the transformed reference image portion with the input image portion;

wherein the motion compensator transforms the reference image portion based on the motion parameter, determines addresses of pels of a transformed reference image portion, and outputs a motion prediction image.

5. The video encoder according to claim 1 or 2, wherein the transformed block matching unit transforms the reference image portion comprised of integer pels and half-pels into an image portion rotated by a predefined angle, determines addresses of pels of a transformed reference image portion, and matches the transformed reference image portion with the input image;

and

wherein the motion compensator transforms the reference image portion based on the motion parameter, determines addresses of pels of a transformed reference image portion, and outputs a motion prediction image.

6. The video encoder according to claim 5, wherein the transformed block matching unit transforms a reference image portion comprised of integer pels and half-pels into an image portion rotated by one of angles of ±

45°

, ±

90°

, ±

135°

, and ±

180°

.

7. The video encoder according to claim 1,

wherein the transformed block matching unit transforms the reference image portion, which has been translated within a search range of the reference image, into one of an image portion scaled up, an image portion scaled down, an image portion rotated by a predefined angle, determines addresses of pels of a transformed reference image portion, and matches the transformed reference image portion with the input image, and

wherein the motion compensator transforms the reference image portion based on the motion parameter, determines addresses of pels of a transformed reference image portion, and outputs a motion prediction image.

8. The video encoder according to claim 1 or 2,

wherein the transformed block matching unit has a transformation pattern table for transforming the reference image portion, and matches the reference image portion transformed according to the transformed value obtained from the transformation pattern table with the input image comprised of integer pels and half-pels, and

wherein the motion compensator transforms the reference image portion based on the motion parameter, determines addresses of pels of a transformed reference image portion, and outputs a motion prediction image.

9. The video encoder according to claim 1 or 2, wherein the transformed block matching unit selectively filters specific pels of the reference image portion extracted for matching, and matches the transformed reference image portion with the input image portion.

10. The video encoder according to claim 1 or 2, wherein the reference image used for detecting the motion is the frame which is forward or backward in time and stored in a frame memory for reference, and wherein the transformed block matching unit matches the transformed reference image portion with the input image using the frame.

11. A video decoder for decoding an input compressed video data, the video decoder including motion compensated prediction means for implementing motion compensation by detecting a motion between frames,

wherein the motion compensated prediction means has a mechanism for determining pels of a corresponding image portion comprised of predefined integer pels by transforming the corresponding reference image portion into a predefined shape according to motion parameters included in the input compressed video data, for extracting the integer pels determined, and for adding the transformed reference image portion and the decoded video signal so as to produce a decoded video data.

12. The video decoder according to claim 11, wherein the motion compensated prediction means further includes a mechanism for determining pels of the corresponding reference image portion comprised of half-pels as well as integer pels by transforming the corresponding reference image portion into one of an image portion scaled up, an image portion scaled down, and an image portion rotated in the same way as a transformed block matching unit of a motion detector comprised in a video encoder corresponding to the video decoder.

14. The video encoding method according to claim 13, wherein the transformed block matching step transforms a reference image portion comprised of half-pels as well as integer pels into an image portion having a predefined shape as a reference, determines addresses of pels of a transformed reference image portion to generate a prediction image portion, and matches the transformed reference image portion with the input digital video.

15. The video encoding method according to claim 13 or 14,

wherein the transformed block matching step further comprises a transformation pattern table, transforms the reference image portion based on transformation value corresponding to an address from the transformation pattern table, and matches the transformed reference image portion with the input digital video.

17. The video decoding method according to claim 16, wherein the motion compensated prediction step transforms a reference image portion comprised of half-pels as well as integer pels into an image portion having a predefined shape, extracts addresses of pels of a transformed reference image portion, and outputs a prediction image portion.

13. A video encoding method for performing compression encoding of an input digital video, comprising:

a motion compensated prediction means for storing a reference image, for dividing the reference image into predefined blocks, and for detecting a motion between frames;

transformed block matching step for transforming a reference image portion comprised of integer pels into an image portion having predefined shape, for determining addresses of pels of a transformed reference image portion to generate a prediction image portion, and for matching the transformed reference image portion with the block of the input digital video;

corresponding pel determining step for determining pels of the reference image portion by using the address of transformed reference image portion based on a motion vector providing a minimum error selected by the transformed block matching step, and for supplying a motion compensated output.

16. A video decoding method for decoding an input compressed video data including a motion compensated prediction means for storing a reference image, for dividing the reference image into predefined blocks, and for implementing a motion compensation between frames, comprising;

a motion compensated prediction step for transforming a reference image portion comprised of predefined integer pels into an image portion having a predefined shape, which corresponds to a video encoding method of a transmitter, based on a reference parameter included in the input compressed video data, for extracting addresses of pels of a transformed reference image portion, and for outputting a prediction image portion; and

decoding adding step for adding the prediction image portion, and for obtaining a reproduced video data.

18. A video encoding/decoding system comprising:

a video encoder for performing compression encoding of input video divided into predefined blocks, including a motion compensated prediction means for implementing a motion compensation by detecting a motion between frames of blocks of an input video, the video encoder comprising;

a motion detector, including a transformed block matching unit for transforming a reference image portion comprised of only integer pels, which consist of real sampling points, into an image portion having a predefined shape, for determining addresses of pels of a transformed reference image portion, and for matching the transformed reference image portion with the block of input video comprised of integer pels, and the motion detector outputting a motion vector providing a minimum prediction error; and

a motion compensator, including a corresponding pel determinator for transforming the reference image portion based on a motion parameter obtained from a comparison result of the transformed block matching unit, and for determining pels corresponding to pels of the reference image portion, and outputting a prediction image portion; and

a video decoder for decoding an input compressed video data, the video decoder including motion compensated prediction means for implementing motion compensation by detecting a motion between frames,

wherein the motion compensated prediction means has a mechanism for determining pels of a corresponding image portion comprised of predefined integer pels by transforming the corresponding reference image portion into a predefined shape according to motion parameters included in the input compressed video data, for extracting the integer pels determined, and for adding the transformed reference image portion and the decoded video signal so as to produce a decoded video data.