METHOD AND SYSTEM FOR PREDICTION OF GAMMA CHARACTERISTICS FOR A DISPLAY

• US 20110109652A1
• Filed: 05/22/2007
• Published: 05/12/2011
• Est. Priority Date: 05/22/2007
• Status: Active Grant

• Current Assignee: InterDigital Madison Patent Holdings (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Lee, Bongsun, Doser, Ingo Tobias
• Granted Patent: US 9,177,499 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165
• CPC Class Codes: H04N 5/202 Gamma control circuits for controlling camera response irrespective of the scene brightness H04N23/82

Abstract

A method and system for gamma adjustment for average power level dependency displays includes applying gamma controlled functions over a range of values at a plurality of average power levels (APLs) for a display. The gamma controlled functions include coefficients for reconstruction of the gamma controlled functions. Upon a change to an APL, interpolation is performed between the coefficients to predict a new gamma controlled function for the new APL.

Claims

1. A method, comprising:

measuring gamma characteristics for a plurality of average power levels of a display to determine respective gamma controlled functions;

determining respective basis vectors and coefficients for the gamma controlled functions of the plurality of average power levels;

in response to a different average power level, interpolating between coefficients associated with known average power levels to determine a respective coefficient and gamma controlled function for the different average power level.

2. The method of claim 1, wherein gamma characteristics are measured by measuring ramp patches.

3. The method of claim 2, wherein ramp patches are measured for each color channel.

4. The method of claim 1, wherein gamma characteristics are measured for each color channel.

5. The method of claim 1, wherein said coefficients are determined using a principal component analysis function.

6. The method of claim 1, wherein said gamma controlled functions are determined from respective gamma curves derived from said measurement.

7. The method of claim 6, wherein said gamma curves are normalized to a common reference.

8. The method of claim 7, wherein said common reference comprises a maximum luminance level.

9. The method of claim 1, further comprising reconstructing at least one of said gamma controlled functions to determine a precision of at least one of said gamma controlled functions.

10. The method of claim 9, wherein said at least one gamma controlled function is reconstructed as a function of input content values, the determined basis vectors and the determined coefficients.

11. The method of claim 1, wherein said determined coefficients are applied to content to be displayed for adjusting luminance values of said input content to be displayed.

12. The method of claim 1, wherein determined coefficients and gamma controlled functions are stored in a memory.

13. A display system, comprising:

a display means configured to display input content;

a storage means configured to store coefficients and gamma controlled functions for a plurality of average power levels;

a sensor configured to determine when a change to an average power level has occurred or a new average power level has been received; and

a processor configured to be responsive to the sensor and in response to a different average power level determined by said sensor, interpolating between coefficients associated with known average power levels to determine a respective coefficient and gamma controlled function for the different average power level.

14. The display system of claim 13, wherein the storage means includes a look up table for storing respective values for gammas associated with average power levels.

15. The display system of claim 13, wherein the stored coefficients are determined using a principal component analysis on the gamma controlled functions.

16. The display system of claim 13, wherein determined respective coefficients and gamma controlled functions are applied to input content having the different average power level for adjusting luminance values of the input content.