Apparatus and method of mapping color gamut

Abstract

A gamut mapping apparatus includes a parameter calculating unit calculating parameters for segmenting a gamut of an output device using gamut information about first and second input color spaces; a gamut segmenting unit segmenting the gamut of the output device into a core gamut and a surround gamut using the parameters; and a gamut mapping unit performing gamut mapping on image data present into the first and second input color spaces to the core gamut and the surround gamut according to a predetermined mapping method. The gamut mapping apparatus and method enable accurate reproduction of image data having components having undergone total internal reflection falling outside the scRGB color space or high chroma components in the scRGB color space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

FIG. 1 is a block diagram showing a gamut mapping apparatus according to an exemplary embodiment of the present invention;

FIG. 2A is a graphical representation describing a procedure of performing gamut mapping according to a first exemplary embodiment of the present invention;

FIG. 2B is a flowchart of the procedure of performing gamut mapping shown in FIG. 2A;

FIG. 3A is a graphical representation describing a procedure of performing gamut mapping according to a second exemplary embodiment of the present invention;

FIG. 3B is a flowchart of the procedure of performing gamut mapping shown in FIG. 3A; and

FIG. 4 is a flowchart of a gamut mapping method according to an exemplary embodiment of the present invention.

Claims

1. A gamut mapping apparatus comprising: a parameter calculating unit for calculating parameters for segmenting a gamut of an output device using gamut information about first and second input color spaces;a gamut segmenting unit for segmenting the gamut of the output device into a core gamut and a surround gamut using the parameters; anda gamut mapping unit for performing gamut mapping on image data present into the first and second input color spaces to the core gamut and the surround gamut according to a predetermined mapping method.

2. The gamut mapping apparatus of claim 1, wherein the first input color space is a sRGB color space and the second input color space is a scRGB color space.

3. The gamut mapping apparatus of claim 2, wherein the parameters are calculated using a ratio of the gamut distribution profile in the scRGB color space to the gamut distribution profile in the scRGB color space.

4. The gamut mapping apparatus of claim 3, wherein when the first input color space completely falls within the second input color space, the parameters α, β, and γ are

5. The gamut mapping apparatus of claim 4, wherein the gamut segmenting unit segments the gamut of the output device into a core gamut and a surround gamut based on Equations WCore=WSurround−αk1(WSurround−KSurround), KCore=KSurround+βk2 (WSurround−KSurround) and CCore=γk3CSurround, wherein WCore, KCore, and CCore indicate the maximum lightness level (white), the maximum lightness level (black), and the minimum chroma level in the gamut in the core color of the output device, respectively, Wsurround, Ksurround, and Csurround indicate the maximum lightness level (white), the minimum lightness level (black), and the maximum chroma level in the gamut in the core color of the output device, and k1, k2, and k3 are scaling factors, respectively.

6. The gamut mapping apparatus of claim 5, wherein the predetermined mapping method is performed such that image data present inside the first color space is mapped to the core gamut and image data present outside the first color space and inside the second color space is mapped to the surround gamut.

7. The gamut mapping apparatus of claim 1, wherein when the first input color space completely falls within the second input color space, a parameter k calculated by the parameter calculating unit is defined by Equation

8. The gamut mapping apparatus of claim 7, wherein the gamut segmenting unit segments the gamut of the output device into a core gamut and a surround gamut based on Equations WCore=kWSurround, KCore=kKSurround, and CCore=kCSurround, wherein WCore, KCore, and CCore indicate the maximum lightness level (white), the maximum lightness level (black), and the minimum chroma level in the gamut in the core color of the output device, respectively, and Wsurround, Ksurround and Csurround indicate the maximum lightness level (white), the minimum lightness level (black), and the maximum chroma level in the gamut in the core color of the output device, respectively.

9. The gamut mapping apparatus of claim 8, wherein the predetermined mapping method is performed such that image data present inside the first color space is mapped to the core gamut and image data present outside the first color space and inside the second color space is mapped to the surround gamut.

10. The gamut mapping apparatus of claim 1, wherein when the input image data falls in the first input color space, the gamut segmenting unit sets the core gamut and the surround gamut of the output device to be matched to each other, and the gamut mapping unit performs gamut mapping on the input image data to the core gamut or the surround gamut of the output device.

11. A color mapping method comprising: calculating parameters for segmenting a gamut of an output device using gamut information about first and second input color spaces;segmenting the gamut of the output device into a core gamut and a surround gamut using the parameters; andperforming gamut mapping on image data present into the first and second input color spaces to the core gamut and the surround gamut according to a predetermined mapping method.

12. The color mapping method of claim 11, wherein the first input color space is a sRGB color space and the second input color space is a scRGB color space.

13. The gamut mapping method of claim 12, wherein the parameters are calculated using a ratio of the gamut distribution profile in the scRGB color space to the gamut distribution profile in the scRGB color space.

14. The gamut mapping method of claim 13, wherein when the first input color space completely falls within the second input color space, the parameters α, β, and γ are

15. The gamut mapping method of claim 14, wherein the segmenting of the gamut of the output device comprises segmenting the gamut based on Equations WCore=WSurround−αk1(WSurround−KSurround), KCore=KSurround+βk2(WSurround−KSurround) and CCore=γk3CSurround, wherein WCore, KCore, and CCore indicate the maximum lightness level (white), the maximum lightness level (black), and the minimum chroma level in the gamut in the core color of the output device, respectively, Wsurround, Ksurround and Csurround indicate the maximum lightness level (white), the minimum lightness level (black), and the maximum chroma level in the gamut in the core color of the output device, and k1, k2, and k3 are scaling factors, respectively.

16. The gamut mapping method of claim 15, wherein the predetermined mapping method is performed such that image data present inside the first color space is mapped to the core gamut and image data present outside the first color space and inside the second color space is mapped to the surround gamut.

17. The gamut mapping method of claim 11, wherein when the first input color space completely falls within the second input color space, a parameter k calculated by the parameter calculating unit is defined by Equation

18. The gamut mapping method of claim 17, wherein the segmenting of the gamut of the output device comprises segmenting the gamut based on Equations WCore=kWSurround, KCore=kKSurround, and CCore=kCSurround, wherein WCore, KCore, and CCore indicate the maximum lightness level (white), the maximum lightness level (black), and the minimum chroma level in the gamut in the core color of the output device, respectively, and Wsurround, Ksurround, and Csurround indicate the maximum lightness level (white), the minimum lightness level (black), and the maximum chroma level in the gamut in the core color of the output device, respectively.

19. The gamut mapping method of claim 18, wherein the predetermined mapping method is performed such that image data present inside the first color space is mapped to the core gamut and image data present outside the first color space and inside the second color space is mapped to the surround gamut.

20. The gamut mapping method of claim 11, wherein when the input image data falls in the first input color space, the segmenting of the gamut comprises setting the core gamut and the surround gamut of the output device to be matched to each other, and the mapping of the gamut comprises performing gamut mapping on the input image data to the core gamut or the surround gamut of the output device.

21. The gamut mapping method of claim 16, wherein the gamut mapping is performed by compression or clipping.

22. A recording medium having a computer readable program recorded therein, the program for executing the method of claim 11.

23. The gamut mapping method of claim 19, wherein the gamut mapping is performed by compression or clipping.