System and Method for Color Space Setting Adjustment

• US 20100277492A1
• Filed: 04/30/2009
• Published: 11/04/2010
• Est. Priority Date: 04/30/2009
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Frederick, John W., Myers, Robert L., Prouty, David Allen
• Granted Patent: US 8,390,642 B2
• Time in Patent Office: Days
• US Class Current: 345/589
• 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 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

Disclosed are various systems and methods of color space setting adjustment. In one embodiment, a system includes an LED RGB backlight as well as a color gamut mapping engine configured to adjust a plurality of input values and output a plurality of adjusted input values to an LCD panel having a native transfer function such that the transformation of the adjusted input values to visible light displayed by the LCD panel complies with user defined color space settings.

Claims

1. A system, comprising:

an LCD panel having a native transfer function configured to transform a plurality of adjusted input values and output a plurality of gamma corrected input values and a native light output function configured to transform the gamma corrected input values into a plurality of light output levels;

an LCD backlight having a plurality of light emitting diode (LED) modules; and

a color gamut mapping engine configured to adjust a plurality of input values corresponding to a video signal and output a plurality of adjusted input values such that the transformation of the adjusted input values to the light output levels complies with at least one color space setting specified by a user; and

a color calibration user interface configured to allow the user to modify the at least one color space setting.

2. The system of claim 1, wherein the color calibration user interface is at least one of:

an on-screen display menu overlaid on the video signal, and color calibration software executable on a computer system.

3. The system of claim 1, wherein the LED modules are configured to emit a combination of red light, green light, and blue light.

4. The system of claim 3, wherein the color calibration user interface is further configured to adjust a white point of the LCD panel by configuring the LCD backlight.

5. The system of claim 4, wherein the white point is adjusted by modifying levels of at least one of:

red light, green light, and blue light emitted by the LED modules.

6. The system of claim 1, wherein the at least one color space setting is at least one of:

primary color chromaticities, transfer function, white point, and luminance.

7. The system of claim 1, wherein the at least one color space setting is an output device specification with which the transformation of the adjusted input values to the output light levels complies.

8. The system of claim 7, wherein the output device specification is at least one of:

sRGB, Adobe RGB, SMPTE-C, and SMPTE-431-2.

9. The system of claim 1, wherein the color gamut mapping engine further comprises:

a color specification transform block configured to apply a transfer function specified by the at least one color setting to the input values and output a gamma corrected input value associated with each of the input values; and

a device compensation block configured to adjust the gamma corrected input value associated with each of the input values and output the adjusted input values.

10. The system of claim 9, wherein the color specification transform block further comprises at least one transfer function lookup table, the at least one transfer function lookup table storing a plurality of possible gamma corrected input values associated with a plurality of possible input values.

11. The system of claim 9, wherein the device compensation block further comprises:

at least one matrix multiplier configured to multiply the gamma corrected input value associated with each of the input values by a transformation matrix and output a plurality of multiplied input values; and

an inverse native transfer function configured to apply an inverse of the native transfer function to the multiplied input values and output the adjusted input values;

wherein

the transformation matrix is a combination of an inverse of the native light output function and a light output function corresponding to the transfer function specified by the at least one color space setting.

12. A method, comprising the steps of:

receiving at least one color space setting from a user;

receiving a plurality of input values corresponding to a video signal;

applying at least one transfer function to the input values and outputting a plurality of gamma corrected input values; and

compensating the gamma corrected input values and outputting a plurality of adjusted input values to an LCD panel having a native transfer function and a native light output function;

wherein

the adjusted input values result in transformation from the input values to light output by the LCD panel according to the at least one color space setting.

13. The method of claim 12, further comprising the step of adjusting levels of at least one of red light, green light and blue light emitted by an LED backlight coupled to the LCD panel, the adjustment being according to the at least one color space setting.

14. The method of claim 12, wherein the at least one color space setting is at least one of:

primary color chromaticities, transfer function, white point, and luminance.

15. The method of claim 12, wherein the at least one color space setting is an output device specification, the output device specification being at least one of:

sRGB, Adobe RGB, SMPTE-C, and SMPTE-431-2.

16. The method of claim 12, wherein the step of compensating the gamma corrected input values further comprises the steps of:

performing a matrix multiplication operation of the gamma corrected input values by a transformation matrix and outputting multiplied input values; and

applying an inverse of the native transfer function to the multiplied input values and outputting the adjusted input values.

17. The method of claim 13, wherein the transformation matrix further comprises a combination of an inverse of the native light output function and a light output function corresponding to the specified output device specification.

18. A computer readable media executable in a computing system, comprising:

logic that receives at least one color space setting from user;

logic that receives a plurality of input values corresponding to a video signal;

logic that applies at least one transfer function to the input values and outputting a plurality of gamma corrected input values; and

logic that compensates the gamma corrected input values and outputting a plurality of adjusted input values to an LCD panel having a native transfer function and a native light output function;

wherein

the adjusted input values result in transformation from the input values to light output by the LCD panel according to the at least one color space setting.

19. The computer readable media of claim 18, wherein the at least one color space setting is at least one of:

primary color chromaticities, transfer function, white point, and luminance.

20. The computer readable media of claim 18, wherein the at least one color space setting is an output device specification, the output device specification being at least one of:

sRGB, Adobe RGB, SMPTE-C, and SMPTE-431-2.