SYSTEMS AND METHODS FOR SELECTIVE HANDLING OF OUT-OF-GAMUT COLOR CONVERSIONS

• US 20090092325A1
• Filed: 09/30/2008
• Published: 04/09/2009
• Est. Priority Date: 10/09/2007
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Higgins, Michael Francis, Brown Elliott, Candice Hellen
• Granted Patent: US 8,295,594 B2
• Time in Patent Office: Days
• US Class Current: 382/232
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607

Abstract

Displays systems and methods for selectively reducing or compressing image data values within an image are recited. Display systems transform input image data from one input gamut hull or space to another target gamut hull or space that is substantially defined by different subpixel repeating groups comprising the display. Display systems described herein comprise a selective compression unit, said unit surveying said input image data to produce intermediate image data based upon a segmentation of the input image according to a parameter. Suitable parameters for segmenting the image include one or more of the following: spatial segments, chromatic segments or temporal segments. A selective compression amount may be determined so as to substantially maintain local contrast of the image data within a given segment.

Claims

1. A display system for rendering input image data onto a display, said display system comprising:

a display, said display comprising a subpixel repeating group, said group comprising colored subpixels of at least four colors, said display having a target gamut space;

a selective compression unit coupled to the display, said unit surveying said input image data to produce intermediate image data wherein said intermediate image data is a function of a segmentation of the input image data according to a parameter; and

a gamut mapping unit coupled to the selective compression unit for mapping said intermediate image data onto image data that is renderable upon the target gamut of said display comprising said subpixel repeating group.

2. The display system as recited in claim 1 wherein said selective compression unit further comprises:

an OOG survey unit for surveying input image data and detecting out of gamut colors in the target gamut of said display;

a segmentation unit that determines which segment of the input image said out of gamut colors reside, wherein said input image comprises a set of segments, said segments determined according to a parameter; and

a scaling map that determines a reduction amount to apply to out of color gamut color depending upon said segment in which said out of color gamut resides.

3. The display system as recited in claim 2 wherein said parameter is at least one of a group, said group comprising:

spatial segments, chromatic segments, and temporal segments.

4. The display system as recited in claim 2 compression unit further comprises:

a selective reduction unit for applying said reduction amount to said out-of-color gamut image data.

5. The display system as recited in claim 4 wherein said reduction amount substantially maintains local contrast of image data.

6. The display system as recited in claim 5 wherein said reduction amount substantially maintains local contrast of image data within said segment of said out-of-gamut image data.

7. A display system for rendering input image data onto a display, said display system comprising:

a display, said display substantially comprising a subpixel repeating group, said group comprising colored subpixels of at least four colors, said display having a target gamut space;

a gamut mapping unit coupled to said display for mapping said input image data onto image data that is substantially renderable upon the target gamut of said display comprising said subpixel repeating group; and

a selective compression unit coupled to said gamut mapping unit, said selective compression unit surveying said image data to produce intermediate image data wherein said intermediate image data is a function of a segmentation of the input image according to a parameter.

8. The display system as recited in claim 7 wherein said selective compression unit further comprises:

an OOG survey unit for surveying image data and detecting out of gamut colors in the target gamut of said display;

a segmentation unit that determines which segment of the image said out of gamut colors reside, wherein said input image comprises a set of segments, said segments determined according to a parameter; and

a scaling map that determines a reduction amount to apply to out of color gamut color depending upon said segment in which said out of color gamut resides.

9. The display system as recited in claim 8 wherein said parameter is at least one of a group, said group comprising:

spatial segments, chromatic segments, and temporal segments.

10. The display system as recited in claim 8 compression unit further comprises:

a selective reduction unit for applying said reduction amount to said out-of-color gamut image data.

11. The display system as recited in claim 10 wherein said reduction amount substantially maintains local contrast of image data.

12. The display system as recited in claim 11 wherein said reduction amount substantially maintains local contrast of image data within said segment of said out-of-gamut image data.

13. A method for selectively compressing input image data within an image, said method comprising:

segmenting an image into a set of segments, said segments determined according to a parameter;

surveying said input image data within each segment to find the out-of-gamut colors in that segment;

for each image data value within a segment, determining a reduction amount to apply to each image data value within each segment; and

reducing each image data value within said segment by the reduction amount, such that the local contrast of the reduced image data is substantially maintained from the input image data.

14. The method as recited in claim 13 wherein said parameter that determines the segmentation of the image comprises at least one of a group, said group comprising a spatial segmentation, a chromatic segmentation and a temporal segmentation.

15. The method as recited in claim 14 wherein said step of determining a reduction amount for each image data value within a segment further comprises:

feathering the reduction amount across other segments to reduce potential visual artifacts.

16. A computer readable medium, said medium comprising an encoding for a method for selectively compressing input image data within an image, said method comprising:

segmenting an image into a set of segments, said segments determined according to a parameter wherein said parameter that determines the segmentation of the image comprises at least one of a group, said group comprising a spatial segmentation, a chromatic segmentation and a temporal segmentation;

surveying said input image data within each segment to find the out-of-gamut colors in that segment;

for each image data value within a segment, determining a reduction amount to apply to each image data value within each segment; and

reducing each image data value within said segment by the reduction amount, such that the local contrast of the reduced image data is substantially maintained from the input image data.

17. The computer readable medium as recited in claim 16 wherein said method further comprises feathering the reduction amount across other segments to reduce potential visual artifacts.