Intensity Compensation Method and Display Control Device and Image Display Device Applying the same

• US 20140327704A1
• Filed: 07/30/2013
• Published: 11/06/2014
• Est. Priority Date: 05/06/2013
• Status: Active Grant

• Current Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited), Novatek Shanghai Co Ltd (Novatek Microelectronics Corp Limited)
• Original Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited), Novatek Shanghai Co Ltd (Novatek Microelectronics Corp Limited)
• Inventors: Wei, Min, Yu, Heng, Jiang, Jiande
• Granted Patent: US 9,177,507 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

An intensity compensation method for a display control device includes steps of obtaining a plurality of backlight duties of a plurality of backlights according to an image data; calculating a plurality of compensation gains according to the plurality of backlight duties and a non-uniform backlight profile, wherein the non-uniform backlight profile indicates a plurality of respective actual intensity distributions of the plurality of backlights; and compensating a plurality of first image intensities corresponding to a plurality of pixels of the image data according to the plurality of compensation gains, to obtain a plurality of second image intensities.

Claims

1. An intensity compensation method for a display control device of an image display device, comprising:

obtaining a plurality of backlight duties of a plurality of backlights according to an image data;

calculating a plurality of compensation gains according to the plurality of backlight duties and a non-uniform backlight profile, wherein the non-uniform backlight profile indicates a plurality of respective actual intensity distributions of the plurality of backlights; and

compensating a plurality of first image intensities corresponding to a plurality of pixels of the image data according to the plurality of compensation gains, to obtain a plurality of second image intensities.

2. The intensity compensation method of claim 1, wherein the step of calculating the plurality of compensation gains according to the plurality of backlight duties and the non-uniform backlight profile comprises:

calculating the compensation gain for each of the plurality of pixels according to multiple backlight duties among the plurality of backlight duties and respective actual intensity distributions of multiple backlights among the plurality of backlights.

3. The intensity compensation method of claim 1, wherein the step of obtaining the plurality of backlight duties of the plurality of backlights according to the image data comprises:

determining the plurality of backlight duties of the plurality of backlights according to a plurality of local image intensities of the image data corresponding to a plurality of display regions corresponding to the plurality of backlights.

4. The intensity compensation method of claim 1, wherein the non-uniform backlight profile comprises a plurality of leakage coefficients P(i,j), where P(i,j) represents an intensity of a j^th pixel among the plurality of pixels of a panel when only an i^th backlight among the plurality of backlights is turned on.

5. The intensity compensation method of claim 4, wherein the step of calculating the plurality of compensation gains according to the plurality of backlight duties and the non-uniform backlight profile comprises:

calculating respective actual backlight intensities at the plurality of pixels according to the plurality of backlight duties and the plurality of leakage coefficients; and

obtaining the plurality of compensation gains according to the respective actual backlight intensities at the plurality of pixels.

6. The intensity compensation method of claim 5, wherein the step of obtaining the plurality of compensation gains according to the respective actual backlight intensities at the plurality of pixels comprises:

calculating a plurality of respective maximum backlight intensities at the plurality of pixels according to the plurality of leakage coefficients under a condition that all of the plurality of backlights are fully turned on; and

calculating the plurality of compensation gains according to the plurality of respective maximum backlight intensities and the respective actual backlight intensities at the plurality of pixels.

7. The intensity compensation method of claim 6, wherein the step of calculating the plurality of compensation gains according to the plurality of respective maximum backlight intensities and the respective actual backlight intensities at the plurality of pixels comprises:

dividing the plurality of respective maximum backlight intensities when all of the pluralities of backlights are fully turned on by the respective actual backlight intensities at the plurality of pixels, respectively, to obtain the plurality of compensation gains.

8. The intensity compensation method of claim 7, wherein the step of calculating the plurality of compensation gains according to the plurality of respective maximum backlight intensities and the respective actual backlight intensities at the plurality of pixels further comprises:

combining a Gamma characteristic of a panel after dividing the plurality of respective maximum backlight intensities by the respective actual backlight intensities, to obtain the plurality of compensation gains.

9. The intensity compensation method of claim 5, wherein the step of obtaining the plurality of compensation gains according to the respective actual backlight intensities at the plurality of pixels comprises:

referring to a look-up table according to the respective actual backlight intensities at the plurality of pixels, to obtain a plurality of gains corresponding to the respective actual backlight intensities at the plurality of pixels and take the plurality of gains as the plurality of compensation gains.

10. A display control device, used in an image display device and coupled to a backlight driving circuit, for receiving an image data and executing the intensity compensation method of claim 1.

11. An image display device, comprising:

a display control device, for receiving an image data and executing the intensity compensation method of claim 1; and

a panel, for receiving control from the display control device for displaying images.

12. The image display device of claim 11 further comprising:

a plurality of backlights, corresponding to a plurality of displaying region; and

a backlight driving circuit, coupled to the display control device, for controlling the plurality of backlights to turn on with a plurality of backlight intensities.

13. The image display device of claim 11, wherein the image display device is a liquid crystal display (LCD).

14. An intensity compensation method for a display control device of an image display device, comprising:

obtaining a plurality of backlight intensities of a plurality of backlights according to an image data;

calculating a plurality of compensation gains according to the plurality of backlight intensities and a non-uniform backlight profile, wherein the non-uniform backlight profile indicates a plurality of respective actual intensity distributions of the plurality of backlights; and

compensating a plurality of first image intensities corresponding to a plurality of pixels of the image data according to the plurality of compensation gains, to obtain a plurality of second image intensities.

15. The intensity compensation method of claim 14, wherein each of the plurality of backlight intensities is defined by at least one among a duty and a magnitude of a control signal.

16. The intensity compensation method of claim 14, wherein the step of calculating the plurality of compensation gains according to the plurality of backlight intensities and the non-uniform backlight profile comprises:

calculating the compensation gain for each of the plurality of pixels according to multiple backlight intensities among the plurality of backlight intensities and respective actual intensity distributions of multiple backlights among the plurality of backlights.

17. The intensity compensation method of claim 14, wherein the step of obtaining the plurality of backlight intensities of the plurality of backlights according to the image data comprises:

determining at least one among a duty and a magnitude of a control signal for each of the plurality of backlights according to a plurality of local image intensities of the image data corresponding to a plurality of display regions corresponding to the plurality of backlights.

18. The intensity compensation method of claim 14, wherein the non-uniform backlight profile comprises a plurality of leakage coefficients P(i,j), where P(i,j) represents an intensity of a j^th pixel among the plurality of pixels of a panel when only an i^th backlight among the plurality of backlights is turned on.

19. The intensity compensation method of claim 18, wherein the step of calculating the plurality of compensation gains according to the plurality of backlight intensities and the non-uniform backlight profile comprises:

calculating respective actual backlight intensities at the plurality of pixels according to the plurality of backlight intensities and the plurality of leakage coefficients; and

obtaining the plurality of compensation gains according to the respective actual backlight intensities at the plurality of pixels.

20. The intensity compensation method of claim 19, wherein the step of obtaining the plurality of compensation gains according to the respective actual backlight intensities at the plurality of pixels comprises:

calculating respective maximum backlight intensities at the plurality of pixels according to the plurality of leakage coefficients under a condition that all of the plurality of backlights are fully turned on; and

calculating the plurality of compensation gains according to the plurality of respective maximum backlight intensities and the respective actual backlight intensities at the plurality of pixels.

21. The intensity compensation method of claim 19, wherein the step of obtaining the plurality of compensation gains according to the respective actual backlight intensities at the plurality of pixels comprises:

referring to a look-up table according to the respective actual backlight intensities at the plurality of pixels, to obtain a plurality of gains corresponding to the respective actual backlight intensities at the plurality of pixels and take the plurality of gains as the plurality of compensation gains.

22. A display control device, used in an image display device and coupled to a backlight driving circuit, for receiving an image data and executing the intensity compensation method of claim 14.

23. An image display device, comprising:

a display control device, for receiving an image data and executing the intensity compensation method of claim 14; and

a panel, receiving instructions from the display control device for displaying images.