Color gamut mapping/enhancement technique using skin color detection

• US 7,933,445 B2
• Filed: 03/29/2007
• Issued: 04/26/2011
• Est. Priority Date: 01/09/2007
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Daly, Scott J., Pan, Hao
• Primary Examiner(s): Alavi; Amir
• Application Number:
  US11/731,095
• Publication Number:
  US 20080166042A1
• Time in Patent Office: 1,489 Days
• Field of Search: 382/162, 382/164, 382/165, 382/167, 382/190, 382/254, 382260-264, 345/589, 345/590, 345600-604, 345/619, 345/622, 358/1.9, 358/504, 358/512, 358/515, 358/518, 358/520, 358/523, 358/525, 358/529, 358/530, 347/15, 347/43, 348/802, 348/E9.024
• US Class Current: 382/167
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only
• CPC Class Codes: H04N 1/628 Memory colours, e.g. skin or sky

Abstract

A method for mapping/enhancing the color of an image to be displayed on a display includes receiving an image having a plurality of pixels where each of the pixels has a plurality of color components. The image is processed using a pair of gamut color mapping operations in combination with skin-tone pixels detection to modify the image in a suitable manner for presentation on the display.

Claims

1. A method for enhancing the color of an image to be displayed on a display comprising:

(a) using a processor to receive an image having a plurality of pixels where each of said pixels has a plurality of color components;

(b) using said processor to modify said image with a first gamut mapping to a first color gamut;

(c) using said processor to modify said image with a second gamut mapping to a second color gamut, wherein said second color gamut is generally different than said first color gamut;

(d) using said processor to determine potential skin-tone pixels of said image;

(e) using said processor to modify said image based upon said first gamut mapping, said second gamut mapping, and said potential skin-tone pixels.

2. The method of claim 1 wherein said first gamut mapping leaves said image substantially unchanged.

3. The method of claim 1 wherein said second gamut mapping substantially changes said image to match that of an input image calibration.

4. The method of claim 1 wherein said second color gamut is generally larger than said first color gamut.

5. The method of claim 1 wherein said potential skin-tone pixels are filtered with a color space filter.

6. The method of claim 1 wherein said first gamut mapping is independent of skin-tones.

7. The method of claim 6 wherein said second gamut mapping is independent of skin-tones.

8. The method of claim 1 wherein said second gamut mapping is independent of skin-tones.

9. The method of claim 1 wherein the values associated with said potential skin-tone pixels are non-binary.

10. The method of claim 1 wherein said potential skin-tone pixels may be modified based upon a gain.

11. The method of claim 10 wherein said gain is user adjustable.

12. The method of claim 1 wherein said potential skin-tone pixels may be modified based upon a hue.

13. The method of claim 12 wherein said hue is user adjustable.

14. The method of claim 1 wherein said potential skin-tone pixels may be based upon saturation.

15. The method of claim 14 wherein said saturation is user adjustable.

16. The method of claim 1 wherein said skin-tone pixels are based upon two dimensional look up tables.

17. The method of claim 1 wherein said skin-tone pixels are also based upon one dimensional look up tables.

18. The method of claim 1 wherein the image is divided into 6 regions of a color space.

19. A method for enhancing the color of an image to be displayed on a display comprising:

(a) using a processor to receive an image having a plurality of pixels where each of said pixels has a plurality of color components;

(b) using said processor to selectively modify a pixel of said image with either a first gamut mapping to a first color gamut or a second gamut mapping to a second color gamut, wherein said second color gamut is generally different than said first color gamut, based upon the likelihood that said pixel is a skin-tone pixel of said image.

20. The method of claim 19 wherein said first gamut mapping leaves said pixel substantially unchanged once displayed.

21. The method of claim 20 wherein said skin-tone pixel is filtered with a spatial filter.

22. The method of claim 19 wherein said first gamut mapping is independent of skin-tones.

23. The method of claim 22 wherein said second gamut mapping is independent of skin-tones.

24. The method of claim 19 wherein said skin-tone pixel may be modified based upon a gain.

25. The method of claim 24 wherein said gain is user adjustable.

26. The method of claim 19 wherein said skin-tone pixel may be modified based upon a hue.

27. The method of claim 26 wherein said hue is user adjustable.

28. The method of claim 19 wherein said skin-tone pixel may be based upon saturation.

29. The method of claim 28 wherein said saturation is user adjustable.