Method And Apparatus For Selectively Applying Input Gamma Dithering

• US 20110025591A1
• Filed: 07/29/2009
• Published: 02/03/2011
• Est. Priority Date: 07/29/2009
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: HAN, Seok-Jin, Hwang, Sarah Sunyoung
• Granted Patent: US 8,203,523 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

Display systems that employ input gamma dithering and dynamic backlight control. Embodiments relate to disabling input gamma dithering during periods when there is a change in the scale value by which image data is scaled due to dynamic backlight control. In this manner, input gamma dithering is selectively applied only during those times when data scaling due to dynamic backlight control is constant.

Claims

1. A method of processing image data, comprising:

receiving a first frame of image data;

determining a first scale value corresponding to a first illumination of a backlight, the first scale value determined at least partially according to the first frame of image data;

receiving a second frame of image data;

determining a second scale value corresponding to a second illumination of the backlight, the second scale value determined at least partially according to the second frame of image data;

enabling input gamma dithering of a third frame of image data when the first scale value is substantially the same as the second scale value; and

disabling input gamma dithering of the third frame of image data when the first scale value is not substantially the same as the second scale value.

2. The method of claim 1:

wherein the method further comprises receiving the image data, the image data being first image data having a first bit depth, and increasing the bit depth of the received image data to a second bit depth greater than the first bit depth, so as to form second image data; and

wherein the input gamma dithering further comprises reducing the bit depth of the second image data by;

for segments of the second image data having least significant bits with a value of binary 0, truncating the segments of the second image data so as to discard the least significant bits; and

for segments of the second image data having least significant bits with a value of binary 1, truncating the segments of the second image data so as to discard the least significant bits, and adding binary 1 to the truncated segments of the second image data.

3. The method of claim 2, wherein the first bit depth is 8 bits, the second bit depth is 12 bits.

4. The method of claim 1, wherein the backlight is a backlight of a liquid crystal display (LCD), and wherein the method further comprises:

displaying images on the LCD according to the first and second frames of image data; and

illuminating the backlight of the LCD according to the first and second illumination when the displayed images corresponding to the first and second frames are respectively displayed on the LCD.

5. The method of claim 1, wherein the first illumination is an illumination of at least a portion of the backlight, and the second illumination is an illumination of at least a portion of the backlight.

6. The method of claim 5, wherein the input gamma dithering is a dithering performed on at least a portion of the second frame of image data.

7. A method of processing image data, comprising:

in a system processing image data and controlling a corresponding illumination of a backlight, enabling input gamma dithering of the image data when the corresponding illumination does not change temporally; and

disabling input gamma dithering when the corresponding illumination changes temporally.

8. The method of claim 7:

wherein the method further comprises receiving the image data, the image data being first image data having a first bit depth, and increasing the bit depth of the received image data to a second bit depth greater than the first bit depth, so as to form second image data; and

wherein the input gamma dithering further comprises reducing the bit depth of the second image data by;

for segments of the second image data having least significant bits with a value of binary 0, truncating the segments of the second image data so as to discard the least significant bits; and

for segments of the second image data having least significant bits with a value of binary 1, truncating the segments of the second image data so as to discard the least significant bits, and adding binary 1 to the truncated segments of the second image data.

9. The method of claim 8, wherein the first bit depth is 8 bits, and the second bit depth is 12 bits.

10. The method of claim 7, wherein the backlight is a backlight of a liquid crystal display (LCD), and wherein the method further comprises:

displaying images on the LCD according to the processed image data; and

illuminating the backlight of the LCD according to the corresponding illumination when the processed image data is displayed on the LCD.

11. The method of claim 7, wherein:

when the corresponding illumination does not substantially change from a first frame of image data to a second frame of image data, the enabling further comprises enabling input gamma dithering of a third frame of image data; and

when the corresponding illumination substantially changes from the first frame of image data to the second frame of image data, the disabling further comprises disabling input gamma dithering of the third frame of image data.

12. The method of claim 7, wherein:

enabling further comprises enabling input gamma dithering when a scale value for gamut correcting the image data according to the corresponding illumination does not change temporally; and

the disabling further comprises disabling input gamma dithering when the scale value changes temporally.

13. A computer-readable memory storing instructions for carrying out a method of processing image data, the method comprising:

in a system processing image data and controlling a corresponding illumination of a backlight, enabling input gamma dithering of the image data when the corresponding illumination does not change temporally; and

disabling input gamma dithering when the corresponding illumination changes temporally.

14. The computer-readable memory of claim 13:

wherein the method further comprises receiving the image data, the image data being first image data having a first bit depth, and increasing the bit depth of the received image data to a second bit depth greater than the first bit depth, so as to form second image data; and

wherein the input gamma dithering further comprises reducing the bit depth of the second image data by;

for segments of the second image data having least significant bits with a value of binary 0, truncating the segments of the second image data so as to discard the least significant bits; and

for segments of the second image data having least significant bits with a value of binary 1, truncating the segments of the second image data so as to discard the least significant bits, and adding binary 1 to the truncated segments of the second image data.

15. The computer-readable memory of claim 14, wherein the first bit depth is 8 bits, and the second bit depth is 12 bits.

16. The computer-readable memory of claim 13, wherein:

when the corresponding illumination does not substantially change from a first frame of image data to a second frame of image data, the enabling further comprises enabling input gamma dithering of a third frame of image data; and

when the corresponding illumination substantially changes from the first frame of image data to the second frame of image data, the disabling further comprises disabling input gamma dithering of the third frame of image data.

17. The computer-readable memory of claim 13, wherein:

the enabling further comprises enabling input gamma dithering when a scale value for gamut correcting the image data according to the corresponding illumination does not change temporally; and

the disabling further comprises disabling input gamma dithering when the scale value changes temporally.

18. A system for processing image data, comprising:

an input gamma block receiving first image data having a first bit depth, and converting the first image data to second image data having a second bit depth;

a dithering block receiving the second image data and performing a dithering operation on the second image data so as to generate third image data having a third bit depth;

a backlight control block controlling an output of a backlight and generating a backlight change signal indicating a change in the output of the backlight; and

logic receiving the backlight change signal and instructing the dithering block to disable the dithering operation when the backlight change signal indicates the change in the output of the backlight.

19. The system of claim 18, wherein the input gamma block is the dithering block.

20. The system of claim 18, wherein the logic further instructs the dithering block to enable the dithering operation when the backlight change signal indicates no change in the output of the backlight.

21. The system of claim 18, wherein the input gamma block is further configured to the bit depth of the second image data by:

for segments of the second image data having least significant bits with a value of binary 0, truncating the segments of the second image data so as to discard the least significant bits; and

for segments of the second image data having least significant bits with a value of binary 1, truncating the segments of the second image data so as to discard the least significant bits, and adding binary 1 to the truncated segments of the second image data.

22. The system of claim 18, wherein the first bit depth is 8 bits, and the second bit depth is 12 bits.