Motion estimation method and apparatus

• US 20010026590A1
• Filed: 02/13/2001
• Published: 10/04/2001
• Est. Priority Date: 02/21/2000
• Status: Active Grant

• Current Assignee: Pantech Corporation (Ideahub, Inc.)
• Original Assignee: Pantech & Curitel Communications Incorporated (Pantech Incorporated)
• Inventors: Kang, Hyun Soo, Kim, Kyeong Joong, Chung, Jae Won
• Granted Patent: US 6,778,606 B2
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/56 Motion estimation with initialisation of the vector search, e.g. estimating a good candidate to initiate a search
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51

Abstract

A motion vector estimation apparatus in a digital video coding system and a method thereof. More particularly, the present invention relates to a motion estimation method and apparatus for, prior to a motion vector estimation operation, determining whether to perform it and selectively performing the motion vector estimation operation in accordance with the determined result, thereby reducing the coding time period and the amount of power consumed.

Claims

1. A motion estimation apparatus comprising:

motion vector estimation determination means for receiving motion vectors and motion prediction errors of macroblocks surrounding a macroblock to be currently coded and determining whether to perform a motion vector estimation operation, on the basis of the received motion vectors and motion prediction errors;

a motion vector estimation unit for performing the motion vector estimation operation in response to a motion vector estimation enable signal from said motion vector estimation determination means;

a switch for selecting one of outputs from said motion vector estimation determination means and motion vector estimation unit in accordance with the result determined by said motion vector estimation determination means; and

a memory for storing an input frame and a reference frame and providing the stored input frame and reference frame to said motion vector estimation determination means and motion vector estimation unit.

2. A motion estimation apparatus as set forth in

claim 1

, wherein said motion vector estimation determination means includes:

a threshold value determination unit for determining a threshold value according to said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded;

a predicted motion vector determination unit for determining a predicted motion vector according to said motion vectors of said surrounding macroblocks;

a motion compensation unit for performing a motion compensation operation using the predicted motion vector determined by said predicted motion vector determination unit; and

a comparator for comparing a motion compensated prediction error from said motion compensation unit with said threshold value determined by said threshold value determination unit.

3. A motion estimation apparatus as set forth in

claim 1

, wherein said macroblocks surrounding said macroblock to be currently coded are three in number.

4. A motion estimation apparatus as set forth in

claim 2

, wherein said threshold value determination unit includes means for determining the sum of absolute differences of one macroblock between a previous frame and a current frame as each of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded.

5. A motion estimation apparatus as set forth in

claim 2

, wherein said comparator is adapted to output a motion vector estimation disable signal to said motion vector estimation unit if said motion compensated prediction error from said motion compensation unit is smaller than or equal to said threshold value from said threshold value determination unit, and said motion vector estimation enable signal to said motion vector estimation unit if said motion compensated prediction error from said motion compensation unit is greater than said threshold value from said threshold value determination unit.

6. A motion estimation apparatus as set forth in

claim 2

, wherein said threshold value determination unit is adapted to determine a median value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

7. A motion estimation apparatus as set forth in

claim 2

, wherein said threshold value determination unit is adapted to determine a maximum value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

8. A motion estimation apparatus as set forth in

claim 2

, wherein said threshold value determination unit is adapted to determine a minimum value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

9. A motion estimation apparatus as set forth in

claim 2

, wherein said threshold value determination unit includes means for, when said macroblock to be currently coded is positioned at an edge of a corresponding frame or a given coding mode is an intraframe coding mode, determining a maximum value of motion prediction errors of macroblocks inside said corresponding frame as a motion prediction error of a macroblock outside said corresponding frame.

10. A motion estimation apparatus as set forth in

claim 2

, wherein said predicted motion vector determination unit is adapted to determine a median value of said motion vectors of said macroblocks surrounding said macroblock to be currently coded, as said predicted motion vector.

11. A motion estimation apparatus as set forth in

claim 2

, wherein said predicted motion vector determination unit is adapted to, when said macroblock to be currently coded is positioned at an edge of a corresponding frame or a given coding mode is an intraframe coding mode, determine a motion vector of said macroblock to be currently coded, to be 0.

12. A motion estimation apparatus comprising:

motion vector estimation determination means for receiving motion vectors and motion prediction errors of macroblocks surrounding a macroblock to be currently coded and determining whether to perform a motion vector estimation operation, on the basis of the received motion vectors and motion prediction errors;

a first motion vector estimation unit for performing the motion vector estimation operation in a relatively large pixel unit in response to a motion vector estimation enable signal from said motion vector estimation determination means;

a switch for selecting one of outputs from said motion vector estimation determination means and first motion vector estimation unit in accordance with the result determined by said motion vector estimation determination means;

a second motion vector estimation unit for performing said motion vector estimation operation in a relatively minute pixel unit using a motion vector selected by said switch; and

a memory for storing an input frame and a reference frame and providing the stored input frame and reference frame to said motion vector estimation determination means, first motion vector estimation unit and second motion vector estimation unit.

13. A motion estimation apparatus as set forth in

claim 12

, wherein said motion vector estimation determination means includes:

a threshold value determination unit for determining a threshold value according to said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded;

a predicted motion vector determination unit for determining a predicted motion vector according to said motion vectors of said surrounding macroblocks;

a motion compensation unit for performing a motion compensation operation using the predicted motion vector determined by said predicted motion vector determination unit; and

a comparator for comparing a motion compensated prediction error from said motion compensation unit with said threshold value determined by said threshold value determination unit.

14. A motion estimation apparatus as set forth in

claim 12

, wherein said first motion vector estimation unit includes means for performing a motion vector searching operation in an integer-pixel unit.

15. A motion estimation apparatus as set forth in

claim 12

, wherein said first motion vector estimation unit includes means for performing a motion vector searching operation in a two-pixel unit.

16. A motion estimation apparatus as set forth in

claim 12

, wherein said second motion vector estimation unit includes means for performing a motion vector searching operation in a half-pixel unit.

17. A motion estimation apparatus as set forth in

claim 13

, wherein said macroblocks surrounding said macroblock to be currently coded are three in number.

18. A motion estimation apparatus as set forth in

claim 13

, wherein said threshold value determination unit includes means for determining the sum of absolute differences of one macroblock between a previous frame and a current frame as each of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded.

19. A motion estimation apparatus as set forth in

claim 13

, wherein said comparator is adapted to output a motion vector estimation disable signal to said first motion vector estimation unit if said motion compensated prediction error from said motion compensation unit is smaller than or equal to said threshold value from said threshold value determination unit, and said motion vector estimation enable signal to said first motion vector estimation unit if said motion compensated prediction error from said motion compensation unit is greater than said threshold value from said threshold value determination unit.

20. A motion estimation apparatus as set forth in

claim 13

, wherein said threshold value determination unit is adapted to determine a median value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

21. A motion estimation apparatus as set forth in

claim 13

, wherein said threshold value determination unit is adapted to determine a maximum value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

22. A motion estimation apparatus as set forth in

claim 13

, wherein said threshold value determination unit is adapted to determine a minimum value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

23. A motion estimation apparatus as set forth in

claim 13

, wherein said threshold value determination unit includes means for, when said macroblock to be currently coded is positioned at an edge of a corresponding frame or a given coding mode is an intraframe coding mode, determining a maximum value of motion prediction errors of macroblocks inside said corresponding frame as a motion prediction error of a macroblock outside said corresponding frame.

24. A motion estimation apparatus as set forth in

claim 13

, wherein said predicted motion vector determination unit is adapted to determine a median value of said motion vectors of said macroblocks surrounding said macroblock to be currently coded, as said predicted motion vector.

25. A motion estimation apparatus as set forth in

claim 13

, wherein said predicted motion vector determination unit is adapted to, when said macroblock to be currently coded is positioned at an edge of a corresponding frame or a given coding mode is an intraframe coding mode, determine a motion vector of said macroblock to be currently coded, to be 0.

26. A motion estimation method comprising the steps of:

a) determining a predicted motion vector referring to a plurality of macroblocks surrounding a macroblock to be currently coded;

b) performing a motion compensated prediction operation for said macroblock to be currently coded, using the predicted motion vector selected at said step a), to obtain a motion compensated prediction error;

c) determining a threshold value using motion prediction errors of said macroblocks surrounding said macroblock to be currently coded;

d) determining whether said motion compensated prediction error obtained at said step b) is smaller than or equal to said threshold value determined at said step c);

e) performing no motion vector estimation operation and determining said predicted motion vector selected at said step a) as a final motion vector, if it is determined at said step d) that said motion compensated prediction error obtained said step b) is smaller than or equal to said threshold value determined at said step c); and

f) performing said motion vector estimation operation to determine an estimated motion vector as the final motion vector, if it is determined at said step d) that said motion compensated prediction error obtained at said step b) is greater than said threshold value determined at said step c).

27. A motion estimation method as set forth in

claim 26

, wherein said macroblocks surrounding said macroblock to be currently coded are three in number.

28. A motion estimation method as set forth in

claim 26

, wherein said step c) includes the step of determining the sum of absolute differences of one macroblock between a previous frame and a current frame as each of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded.

29. A motion estimation method as set forth in

claim 26

, wherein said step c) includes the step of determining a median value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

30. A motion estimation method as set forth in

claim 26

, wherein said step c) includes the step of determining a maximum value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

31. A motion estimation method as set forth in

claim 26

, wherein said step c) includes the step of determining a minimum value of said motion prediction errors of said macroblocks surrounding said macroblock to be currently coded, as said threshold value.

32. A motion estimation method as set forth in

claim 26

, wherein said step c) includes the step of, when said macroblock to be currently coded is positioned at an edge of a corresponding frame or a given coding mode is an intraframe coding mode, determining a maximum value of motion prediction errors of macroblocks inside said corresponding frame as a motion prediction error of a macroblock outside said corresponding frame.

33. A motion estimation method as set forth in

claim 26

, wherein said step a) includes the step of determining a median value of said motion vectors of said macroblocks surrounding said macroblock to be currently coded, as said predicted motion vector.

34. A motion estimation method as set forth in

claim 26

, wherein said step a) includes the step of, when said macroblock to be currently coded is positioned at an edge of a corresponding frame or a given coding mode is an intraframe coding mode, determining a motion vector of said macroblock to be currently coded, to be 0.