ENHANCED HISTOGRAM EQUALIZATION

• US 20110285913A1
• Filed: 07/14/2011
• Published: 11/24/2011
• Est. Priority Date: 05/21/2010
• Status: Active Grant

• Current Assignee: VIXS Systems Incorporated (Pixelworks Incorporated)
• Original Assignee: VIXS Systems Incorporated (Pixelworks Incorporated)
• Inventors: Astrachan, Paul M.
• Granted Patent: US 8,698,961 B2
• Time in Patent Office: Days
• US Class Current: 348/687
• CPC Class Codes: H04N 21/4318 by altering the content in the rendering process, e.g. blanking, blurring or masking an image region image enhancement or restoration in general G06T5/00
• CPC Class Codes: H04N 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 5/57 Control of contrast or brightness

Abstract

A video processor includes a video stream translation module configured to generate a translated luminance value for a pixel of a current frame of a video data stream. The translated luminance value is based on a first luminance value for the pixel and a first translation matrix for the current frame of the video data stream. The video processor includes a filter configured to generate an output luminance value for the pixel based on the translated luminance value and a target translated luminance value for the pixel. The output luminance value may be based on a weighted average of the translated luminance value and the target translated luminance value using a first weighting factor. The video processor may include a first weighting factor generator configured to generate the first weighting factor based on luminance values of the current frame of the video stream.

Claims

1. An apparatus comprising:

a video stream translation module configured to generate a translated luminance value for a pixel of a current frame of a video data stream, the translated luminance value being based on a first luminance value for the pixel and a first translation matrix for the current frame of the video data stream; and

a filter configured to generate an output luminance value for the pixel based on the translated luminance value and a target translated luminance value.

2. The apparatus, as recited in claim 1, wherein the output luminance value is based on a weighted average of the translated luminance value and the target translated luminance value using a first weighting factor.

3. The apparatus, as recited in claim 2, further comprising:

a first weighting factor generator configured to generate the first weighting factor based on luminance values of the current frame of the video data stream.

4. The apparatus, as recited in claim 3, wherein the first weighting factor is proportional to an average luminance of the current frame of the video data stream.

5. The apparatus, as recited in claim 1, further comprising:

a target pixel generator configured to generate the target luminance value based on a target translation matrix and the first luminance value.

6. The apparatus, as recited in claim 5, wherein the target translation matrix is a linear function.

7. The apparatus, as recited in claim 5, wherein the target translation matrix is a non-linear function.

8. The apparatus, as recited in claim 1, further comprising:

a translation matrix generator configured to generate the first translation matrix based on a second translation matrix for the current frame of the video data stream, a prior first translation matrix for a prior frame of data, and a weighting factor.

9. The apparatus, as recited in claim 8, further comprising:

a weighting factor generator configured to generate the weighting factor based on luminance values of the current frame of the video data stream.

10. The apparatus, as recited in claim 9, wherein the weighting factor is a weight of the second translation matrix and the weighting factor is proportional to an average luminance of the current frame of the video data stream.

11. A method comprising:

generating a translated luminance value for a pixel of a current frame of a video data stream, the translated luminance value being based on a first luminance value for the pixel and a first translation matrix for the current frame of the video data stream; and

generating an output luminance value for the pixel based on the translated luminance value and a target translated luminance value for the pixel.

12. The method, as recited in claim 11, further comprising:

generating the target translated luminance value based on a target translation matrix for the current frame of the video data stream and the first luminance value.

13. The method, as recited in claim 11, wherein the output luminance value is based on a weighted average of the translated luminance value and the target translated luminance value using a first weighting factor.

14. The method, as recited in claim 13, further comprising:

updating the first weighting factor based on luminance values of the current frame of the video stream.

15. The method, as recited in claim 14, wherein the first weighting factor is proportional to an average luminance of the current frame of the video data stream.

16. The method, as recited in claim 12, wherein the target translation matrix is a linear function.

17. The method, as recited in claim 12, wherein the target translation matrix is a non-linear function.

18. The method, as recited in claim 11, further comprising:

generating the first translation matrix based on a second translation matrix for the current frame of the video data stream, a prior first translation matrix for a prior frame of data, and a weighting factor.

19. The method, as recited in claim 18, further comprising:

generating the weighting factor based on luminance values of the current frame of the video stream.

20. The method, as recited in claim 19, wherein the weighting factor is a weight of the second translation matrix and the weighting factor is proportional to an average luminance of the current frame of the video data stream.

21. A tangible computer-readable medium encoding a representation of an integrated circuit that comprises:

a video stream translation module configured to generate a translated luminance value for a pixel of a current frame of a video data stream, the translated luminance value being based on a first luminance value for the pixel and a first translation matrix for the current frame of the video data stream; and

a filter configured to generate an output luminance value for the pixel based on the translated luminance value and a target translated luminance value.

22. The tangible computer-readable medium, as recited in claim 21, wherein the integrated circuit further comprises:

a target pixel generator configured to generate the target luminance value based on a target translation matrix and the first luminance value.

23. The tangible computer-readable medium, as recited in claim 21,

wherein the output luminance value is based on a weighted average of the translated luminance value and the target translated luminance value using a first weighting factor,

wherein the integrated circuit further comprises:

a first weighting factor generator configured to generate a first weighting factor based on luminance values of the current frame of the video stream.

24. An apparatus comprising:

a video stream translation module configured to generate a translated luminance value for a pixel of a current frame of a video data stream, the translated luminance value being based on a first luminance value for the pixel and a first translation matrix for the current frame of the video data stream; and

a translation matrix generator configured to generate the first translation matrix based on a second translation matrix for a current frame of a video data stream, a prior translation matrix for a prior frame of the video data stream, and a weighting factor.

25. The apparatus, as recited in claim 24, further comprising:

a weighting factor generator configured to generate the weighting factor based on luminance values of the current frame of the video stream.

26. The apparatus, as recited in claim 24, wherein the weighting factor is a weight of the second translation matrix and the weighting factor is proportional to an average luminance of the current frame of the video data stream.