Processing a video signal using motion estimation to separate luminance information from chrominance information in the video signal

• US 20040189875A1
• Filed: 03/31/2003
• Published: 09/30/2004
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Zhai, Fan, Renner, Karl H.
• Granted Patent: US 7,046,306 B2
• Time in Patent Office: Days
• US Class Current: 348/669
• CPC Class Codes: H04N 9/78 for separating the brightness signal or the chrominance signal from the colour television signal, e.g. using comb filter

Abstract

In one embodiment, a method for processing a video signal includes: (1) receiving and storing luminance and chrominance information for each pixel in a first portion of the signal; (2) receiving luminance and chrominance information for each pixel in a second portion of the signal; (3) determining an estimated motion vector for each particular pixel of the second portion by comparing the luminance and chrominance information of the particular pixel to the stored luminance and chrominance information for one or more pixels in a search area of the first portion to determine a pixel in the search area that most closely matches the particular pixel and determining the estimated motion vector according to the particular pixel and the most closely matching pixel; (4) using the estimated motion vector to access the chrominance information for the most closely matching pixel; (5) using a three-dimensional comb filter to filter the chrominance information for the particular pixel and for the most closely matching pixel to determine three-dimensional filter output chrominance information for the particular pixel; (6) receiving the three-dimensional output chrominance information and if the chrominance information for the particular pixel matches the chrominance information of the most closely matching pixel within a specified tolerance, using the three-dimensional filter output chrominance information to determine output luminance information for the particular pixel; and (7) providing the three-dimensional output chrominance information and output luminance information for the particular pixel for displaying the particular pixel.

Claims

1. A system for processing a video signal comprising information for a plurality of frames, each frame representing an image and comprising a plurality of pixels, each pixel having luminance information and chrominance information, the system comprising:

a motion estimator operable to;

receive the luminance information and chrominance information for each pixel in a first predetermined portion of the video signal, the first predetermined portion comprising at least a first frame;

store the received luminance information and chrominance information for the pixels in the first predetermined portion of the video signal;

receive the luminance information and chrominance information for each pixel in a second predetermined portion of the video signal, the second predetermined portion comprising at least a second frame; and

for each particular pixel of the second predetermined portion, determine an estimated motion vector for the particular pixel of the second predetermined portion by;

comparing the luminance information and chrominance information of the particular pixel of the second predetermined portion to the stored luminance information and chrominance information for one or more pixels in a search area of the first predetermined portion to determine a pixel in the search area of the first predetermined portion that most closely matches the particular pixel of the second predetermined portion; and

determining the estimated motion vector according to the particular pixel of the second predetermined portion and the most closely matching pixel in the search area of the first predetermined portion, the estimated motion vector being used to access the chrominance information for the most closely matching pixel in the search area of the first predetermined portion;

a three-dimensional comb filter operable to filter the chrominance information for the particular pixel of the second predetermined portion and the chrominance information for the most closely matching pixel in the search area of the first predetermined portion to determine three-dimensional filter output chrominance information for the particular pixel of the second predetermined portion; and

an output processor operable to;

receive the three-dimensional output chrominance information for the particular pixel of the second predetermined portion;

if the chrominance information for the particular pixel of the second predetermined portion matches the chrominance information of the most closely matching pixel in the search area of the first predetermined portion within a specified tolerance, use the three-dimensional filter output chrominance information to determine output luminance information for the particular pixel of the second predetermined portion; and

provide the three-dimensional output chrominance information for the particular pixel and the output luminance information for the particular pixel for displaying the particular pixel.

2. The system of claim 1, wherein the video signal comprises a composite analog video signal and the system further comprises a digitizer operable to receive and digitize the composite analog video signal.

3. The system of claim 1, further comprising a predictor operable to use the estimated motion vector to access the chrominance information for the most closely matching pixel in the search area of the first predetermined portion.

4. The system of claim 1, wherein the motion estimator is further operable to determine a motion intensity for the particular pixel of the second predetermined portion as a measure of the similarity of the particular pixel of the second predetermined portion to the most closely matching pixel in the search area of the first predetermined portion.

5. The system of claim 4, further comprising:

a two-dimensional comb filter operable to filter the chrominance information of the particular pixel of the second predetermined portion to generate two-dimensional filter output chrominance information; and

a mixer operable to determine final output chrominance information for the particular pixel of the second predetermined portion using the motion intensity determined by the motion estimator, the two-dimensional filter output chrominance information, and the three-dimensional output chrominance information.

6. The system of claim 5, wherein if the motion intensity determined by the motion estimator is greater than a predetermined threshold, the mixer determines the final output chrominance information to be equal to the two-dimensional filter output chrominance information.

7. The system of claim 1, wherein the output processor is operable to communicate the three-dimensional filter output chrominance information for the particular pixel in the second predetermined portion to a chrominance modulator, the chrominance modulator operable to subtract the three-dimensional filter output chrominance information for the particular pixel in the second predetermined portion from a portion of the video signal corresponding to the particular pixel in the second predetermined portion to determine the output luminance information for the particular pixel in the second predetermined portion.

8. The system of claim 1, wherein the output processor is further operable to accumulate the three-dimensional output chrominance information and the output luminance information for each pixel in an entire frame before sending an output signal comprising the three-dimensional output chrominance information and the output luminance information for each pixel in the entire frame.

9. The system of claim 1, wherein the video signal comprises a National Television System Committee (NTSC) composite video signal and each frame comprises five hundred twenty-five lines.

10. The system of claim 1, wherein the first predetermined portion and the second predetermined portion each comprise one entire frame and sixteen lines of a next sequential frame.

11. The system of claim 1, wherein the system comprises at least one of:

a television;

a video cassette recorder; and

a laser disc player.

12. A method for processing a video signal comprising information for a plurality of frames, each frame representing an image and comprising a plurality of pixels, each pixel having luminance information and chrominance information, the method comprising:

receiving the luminance information and chrominance information for each pixel in a first predetermined portion of the video signal, the first predetermined portion comprising at least a first frame;

storing the received luminance information and chrominance information for the pixels in the first predetermined portion of the video signal;

receiving the luminance information and chrominance information for each pixel in a second predetermined portion of the video signal, the second predetermined portion comprising at least a second frame;

for each particular pixel of the second predetermined portion, determining an estimated motion vector for the particular pixel of the second predetermined portion by;

comparing the luminance information and chrominance information of the particular pixel of the second predetermined portion to the stored luminance information and chrominance information for one or more pixels in a search area of the first predetermined portion to determine a pixel in the search area of the first predetermined portion that most closely matches the particular pixel of the second predetermined portion; and

determining the estimated motion vector according to the particular pixel of the second predetermined portion and the most closely matching pixel in the search area of the first predetermined portion;

using the estimated motion vector to access the chrominance information for the most closely matching pixel in the search area of the first predetermined portion;

using a three-dimensional comb filter to filter the chrominance information for the particular pixel of the second predetermined portion and the chrominance information for the most closely matching pixel in the search area of the first predetermined portion to determine three-dimensional filter output chrominance information for the particular pixel of the second predetermined portion;

receiving the three-dimensional output chrominance information for the particular pixel of the second predetermined portion;

if the chrominance information for the particular pixel of the second predetermined portion matches the chrominance information of the most closely matching pixel in the search area of the first predetermined portion within a specified tolerance, using the three-dimensional filter output chrominance information to determine output luminance information for the particular pixel of the second predetermined portion; and

providing the three-dimensional output chrominance information for the particular pixel and the output luminance information for the particular pixel for displaying the particular pixel.

13. The method of claim 12, wherein the video signal comprises a composite analog video signal and the system further comprises a digitizer operable to receive and digitize the composite analog video signal.

14. The method of claim 12, further comprising determining a motion intensity for the particular pixel of the second predetermined portion as a measure of the similarity of the particular pixel of the second predetermined portion to the most closely matching pixel in the search area of the first predetermined portion.

15. The method of claim 14, further comprising:

using a two-dimensional comb filter to filter the chrominance information of the particular pixel of the second predetermined portion to generate two-dimensional filter output chrominance information; and

determining final output chrominance information for the particular pixel of the second predetermined portion using the motion intensity, the two-dimensional filter output chrominance information, and the three-dimensional output chrominance information.

16. The method of claim 15, further comprising determining the final output chrominance information to be equal to the two-dimensional filter output chrominance information if the motion intensity greater than a predetermined threshold.

17. The method of claim 12, further comprising subtracting the three-dimensional filter output chrominance information for the particular pixel in the second predetermined portion from a portion of the video signal corresponding to the particular pixel in the second predetermined portion to determine the output luminance information for the particular pixel in the second predetermined portion.

18. The method of claim 12, further comprising accumulating the three-dimensional output chrominance information and the output luminance information for each pixel in an entire frame before sending an output signal comprising the three-dimensional output chrominance information and the output luminance information for each pixel in the entire frame.

19. The method of claim 12, wherein the video signal comprises a National Television System Committee (NTSC) composite video signal and each frame comprises five hundred twenty-five lines.

20. The method of claim 12, wherein the first predetermined portion and the second predetermined portion each comprise one entire frame and sixteen lines of a next sequential frame.

21. The method of claim 12, wherein the method is executed by one or more components of at least one of:

a television;

a video cassette recorder; and

a laser disc player.

22. Logic encoded in media for processing a video signal comprising information for a plurality of frames, each frame representing an image and comprising a plurality of pixels, each pixel having luminance information and chrominance information, the logic when executed operable to:

receive the luminance information and chrominance information for each pixel in a first predetermined portion of the video signal, the first predetermined portion comprising at least a first frame;

store the received luminance information and chrominance information for the pixels in the first predetermined portion of the video signal;

receive the luminance information and chrominance information for each pixel in a second predetermined portion of the video signal, the second predetermined portion comprising at least a second frame;

for each particular pixel of the second predetermined portion, determine an estimated motion vector for the particular pixel of the second predetermined portion by;

comparing the luminance information and chrominance information of the particular pixel of the second predetermined portion to the stored luminance information and chrominance information for one or more pixels in a search area of the first predetermined portion to determine a pixel in the search area of the first predetermined portion that most closely matches the particular pixel of the second predetermined portion; and

determining the estimated motion vector according to the particular pixel of the second predetermined portion and the most closely matching pixel in the search area of the first predetermined portion;

use the estimated motion vector to access the chrominance information for the most closely matching pixel in the search area of the first predetermined portion;

use a three-dimensional comb filter to filter the chrominance information for the particular pixel of the second predetermined portion and the chrominance information for the most closely matching pixel in the search area of the first predetermined portion to determine three-dimensional filter output chrominance information for the particular pixel of the second predetermined portion;

receive the three-dimensional output chrominance information for the particular pixel of the second predetermined portion;

if the chrominance information for the particular pixel of the second predetermined portion matches the chrominance information of the most closely matching pixel in the search area of the first predetermined portion within a specified tolerance, use the three-dimensional filter output chrominance information to determine output luminance information for the particular pixel of the second predetermined portion; and

provide the three-dimensional output chrominance information for the particular pixel and the output luminance information for the particular pixel for displaying the particular pixel.

23. The logic of claim 22, wherein the video signal comprises a composite analog video signal and the system further comprises a digitizer operable to receive and digitize the composite analog video signal.

24. The logic of claim 22, further operable to determine a motion intensity for the particular pixel of the second predetermined portion as a measure of the similarity of the particular pixel of the second predetermined portion to the most closely matching pixel in the search area of the first predetermined portion.

25. The logic of claim 24, further operable to:

use a two-dimensional comb filter to filter the chrominance information of the particular pixel of the second predetermined portion to generate two-dimensional filter output chrominance information; and

determine final output chrominance information for the particular pixel of the second predetermined portion using the motion intensity, the two-dimensional filter output chrominance information, and the three-dimensional output chrominance information.

26. The logic of claim 25, further operable to determine the final output chrominance information to be equal to the two-dimensional filter output chrominance information if the motion intensity greater than a predetermined threshold.

27. The logic of claim 22, further operable to subtract the three-dimensional filter output chrominance information for the particular pixel in the second predetermined portion from a portion of the video signal corresponding to the particular pixel in the second predetermined portion to determine the output luminance information for the particular pixel in the second predetermined portion.

28. The logic of claim 22, further operable to accumulate the three-dimensional output chrominance information and the output luminance information for each pixel in an entire frame before sending an output signal comprising the three-dimensional output chrominance information and the output luminance information for each pixel in the entire frame.

29. The logic of claim 22, wherein the video signal comprises a National Television System Committee (NTSC) composite video signal and each frame comprises five hundred twenty-five lines.

30. The logic of claim 29, wherein the first predetermined portion and the second predetermined portion each comprise one entire frame and sixteen lines of a next sequential frame.

31. The logic of claim 22, wherein the logic is executed by one or more components of at least one of:

a television;

a video cassette recorder; and

a laser disc player.