MOTION COMPENSATOR, MOTION COMPENSATION PROCESSING METHOD AND COMPUTER PROGRAM

Abstract

A motion compensator detects a first shift amount between temporally adjacent first and second frames, wherein the first shift amount is detected based upon a differential value between pixels constituting the first frame and pixels constituting the second frame; stores in a storing unit of information of the detected first shift amount with regard to each reference frame candidate; calculates a second shift amount between the input frame and each reference frame candidate based upon the first shift amount or a sum of the first shift amount from each reference frame candidate to the input frame; selects a reference frame candidate for which the second shift amount is smallest as a reference frame; and calculates a motion vector, with regard to each macro block of the input frame, based upon each macro block of the reference frame.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of the configuration of a motion compensator corresponding to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating an example of the states of reference frame candidates and a current frame corresponding to the first embodiment of the present invention;

FIG. 3 is a flowchart illustrating an example of operation of the motion compensator corresponding to the first embodiment of the present invention;

FIG. 4 is a diagram illustrating an example of the configuration of a motion compensator corresponding to a second embodiment of the present invention;

FIG. 5 is a diagram illustrating an example of division of an image into blocks corresponding to the first embodiment of the present invention; and

FIG. 6 is a diagram illustrating an example of the results of calculating a global vector between adjacent frames corresponding to the first embodiment of the present invention.

Claims

1. A motion compensator for performing motion compensation using image information of an input frame and image information of any reference frame candidate among a plurality of reference frame candidates, comprising: a detection unit for detecting a first shift amount between temporally adjacent first and second frames, wherein the first shift amount is detected based upon a differential value between pixels constituting the first frame and pixels constituting the second frame;a storing unit for storing information of the first shift amount detected by said detection unit with regard to each of the plurality of reference frame candidates;a calculation unit for calculating a second shift amount between the input frame and each of the plurality of reference frame candidates based upon the first shift amount or a sum of the first shift amount from each of the plurality of reference frame candidates to the input frame;a selection unit for selecting a reference frame candidate for which the second shift amount is smallest as a reference frame; anda motion vector calculation unit for calculating a motion vector, with regard to each macro block that constitutes the input frame, based upon each macro block that constitutes the reference frame.

2. The motion compensator according to claim 1, wherein said selection unit selects the reference frame candidate as the reference frame for which a shift amount is smallest among the first shift amount detected between the input frame and a reference frame candidate that is temporally adjacent to the input frame, and the second shift amounts found between the input frame and other reference frame candidates that are not temporally adjacent to the input frame.

3. The motion compensator according to claim 1, wherein in a case where the first shift amount that has been detected with regard to the input frame between the input frame and a reference frame candidate that is temporally adjacent to the input frame exceeds a predetermined threshold value, said selection unit selects a reference frame candidate for which the second shift amount is smallest as the reference frame.

4. The motion compensator according to claim 1, wherein in a case where an evaluation value of the second shift amount of the reference frame candidate for which the second shift amount is smallest exceeds a predetermined threshold value, said selection unit selects a reference frame candidate that is temporally adjacent to the input frame as the reference frame; and the evaluation value is calculated using a minimum differential value for detecting each of the first shift amounts of the input frame and the reference frame candidate situated between the reference frame candidate for which the second shift amount is smallest and the input frame.

5. The motion compensator according to claim 1, wherein said calculation unit calculates the second shift amount by the sum of the first shift amounts of frames included between the input frame and any of the plurality of reference frame candidates.

6. The motion compensator according to claim 1, wherein the input frame and reference frame candidates are each divided into a plurality of areas and the first and second shift amounts are found with regard to each of the areas.

7. A motion compensator for performing motion compensation using image information of an input frame and image information of any reference frame candidate among a plurality of reference frame candidates, comprising: a detection unit for detecting a first shift amount between temporally adjacent two frames, wherein the first shift amount is detected based upon a differential value of pixels between the two frames;a storing unit for storing information of the first shift amount detected by said detection unit with regard to each of the plurality of reference frame candidates;a calculation unit for calculating a second shift amount based upon a sum of the first shift amount from each of the plurality of reference frame candidates to the input frame;a selection unit for selecting a reference frame to be used in an inter-frame prediction of the input frame among the plurality of reference frame candidates based on a result of a calculation by said calculation unit; anda motion vector calculation unit for calculating a motion vector between the input frame and the reference frame selected by said selection unit.

8. A motion compensation processing method of performing motion compensation using image information of an input frame and image information of any reference frame candidate among a plurality of reference frame candidates, comprising: a detection step of detecting a first shift amount between temporally adjacent first and second frames, wherein the first shift amount is detected based upon a differential value between pixels constituting the first frame and pixels constituting the second frame;a storing step of storing information of the first shift amount detected in said detection step with regard to each of the plurality of reference frame candidates;a calculation step of calculating a second shift amount between the input frame and each of the plurality of reference frame candidates based upon the first shift amount or a sum of the first shift amount from each of the plurality of reference frame candidates to the input frame;a selection step of selecting a reference frame candidate for which the second shift amount is smallest as a reference frame; anda motion vector calculation step of calculating a motion vector, with regard to each macro block that constitutes the input frame, based upon each macro block that constitutes the reference frame.

9. The method according to claim 8, wherein said selection unit selects the reference frame candidate as the reference frame for which a shift amount is smallest among the first shift amount detected between the input frame and a reference frame candidate that is temporally adjacent to the input frame, and the second shift amounts found between the input frame and other reference frame candidates that are not temporally adjacent to the input frame.

10. The method according to claim 8, wherein in a case where the first shift amount that has been detected with regard to the input frame between the input frame and a reference frame candidate that is temporally adjacent to the input frame exceeds a predetermined threshold value, a reference frame candidate for which the second shift amount is smallest is selected as the reference frame at said selection step

11. The method according to claim 8, wherein in a case where an evaluation value of the shift amount of the second reference frame candidate for which the second shift amount is smallest exceeds a predetermined threshold value, a reference frame candidate that is temporally adjacent to the input frame is selected as the reference frame at said selection step; and the evaluation value is calculated using a minimum differential value for detecting each of the first shift amounts of the input frame and the reference frame candidate situated between the reference frame candidate for which the second shift amount is smallest and the input frame.

12. The method according to claim 8, wherein the second shift amount is calculated at said calculation step by the sum of the first shift amounts of frames included between the input frame and any of the plurality of reference frame candidates.

13. The method according to claim 8, wherein the input frame and reference frame candidates are each divided into a plurality of areas and the first and second shift amounts are found with regard to each of the areas.

14. A motion compensation processing method of performing motion compensation using image information of an input frame and image information of any reference frame candidate among a plurality of reference frame candidates, comprising: a detection step for detecting a first shift amount between temporally adjacent two frames, wherein the first shift amount is detected based upon a differential value of pixels between the two frames;a storing step for storing information of the first shift amount detected in said detection step with regard to each of the plurality of reference frame candidates;a calculation step for calculating a second shift amount based upon a sum of the first shift amount from each of the plurality of reference frame candidates to the input frame;a selection step for selecting a reference frame to be used in an inter-frame prediction of the input frame among the plurality of reference frame candidates based on a result of a calculation in said calculation step; anda motion vector calculation step for calculating a motion vector between the input frame and the reference frame selected in said selection step.

15. A computer program stored in a computer-readable storage medium, wherein said computer program causes a computer to function as a motion compensator for performing motion compensation using image information of an input frame and image information of any reference frame candidate among a plurality of reference frame candidates, said motion compensator comprising: a detection unit for detecting a first shift amount between temporally adjacent first and second frames, wherein the first shift amount is detected based upon a differential value between pixels constituting the first frame and pixels constituting the second frame;a storing unit for storing information of the first shift amount detected by said detection unit with regard to each of the plurality of reference frame candidates;a calculation unit for calculating a second shift amount between the input frame and each of the plurality of reference frame candidates based upon the first shift amount or a sum of the first shift amount from each of the plurality of reference frame candidates to the input frame;a selection unit for selecting a reference frame candidate for which the second shift amount is smallest as a reference frame; anda motion vector calculation unit for calculating a motion vector, with regard to each macro block that constitutes the input frame, based upon each macro block that constitutes the reference frame.

16. A computer program stored in a computer-readable storage medium, wherein said computer program causes a computer to function as a motion compensator for performing motion compensation using image information of an input frame and image information of any reference frame candidate among a plurality of reference frame candidates, said motion compensator comprising: a detection unit for detecting a first shift amount between temporally adjacent two frames, wherein the first shift amount is detected based upon a differential value of pixels between the two frames;a storing unit for storing information of the first shift amount detected by said detection unit with regard to each of the plurality of reference frame candidates;a calculation unit for calculating a second shift amount based upon a sum of the first shift amount from each of the plurality of reference frame candidates to the input frame;a selection unit for selecting a reference frame to be used in an inter-frame prediction of the input frame among the plurality of reference frame candidates based on a result of a calculation by said calculation unit; anda motion vector calculation unit for calculating a motion vector between the input frame and the reference frame selected by said selection unit.