ADAPTIVE TEMPORAL DITHER SCHEME FOR DISPLAY DEVICES

• US 20140192079A1
• Filed: 01/04/2013
• Published: 07/10/2014
• Est. Priority Date: 01/04/2013
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Lee, Jeho, Parmar, Manu, Chuei, Nao S., Aflatooni, Koorosh, Lewis, Alan G., Chui, Clarence
• Application Number:
  US13/734,704
• Publication Number:
  US 20140192079A1
• Time in Patent Office: Days
• US Class Current: 345/597
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/204 the sub-frames being organized in consecutive sub-frame groups
• CPC Class Codes: G09G 3/2055 the pattern being varied in time
• 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

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for displaying high resolution images using an adaptive temporal dithering scheme on display devices having two or more color planes. The adaptive temporal dithering scheme includes identifying the dither visibility of an image to be displayed by the color planes and adaptively applying temporal dithering to the color plane having the highest dither visibility. In one aspect, temporal dithering can be adaptively applied between two different color planes on a frame-by-frame basis based at least partly on the dither visibility of the image content.

Claims

1. An apparatus comprising:

a display device having a plurality of display pixels, each display pixel configured to display a plurality of colors in a color space associated with the display device; and

a processor configured to communicate with the display device, the processor configured to process image data for display by the display device, the image data including a plurality of image pixels, the processor configured to;

map the image data to the plurality of display pixels to provide data associated with each color plane in the color space associated with the display device, the color plane data including a color value for each display pixel in the display device;

for each color plane;

identify display pixels having spatial frequencies below a threshold,

for each of the identified display pixels, calculate a dither visibility score based at least in part on comparison of the color value for the display pixel and a dither visibility function for the color plane, and

determine an accumulated dither visibility score for the color plane; and

apply temporal dither to a subset of the plurality of color planes based on the determined accumulated dither visibility scores.

2. The apparatus of claim 1, wherein the processor is configured to apply temporal dither to the color plane determined to have the highest accumulated dither visibility score.

3. The apparatus of claim 2, wherein the processor is further configured to apply temporal dither to the color plane determined to have the second-highest accumulated dither visibility score.

4. The apparatus of claim 3, wherein the temporal dither applied to the color plane determined to have the second-highest accumulated dither visibility score is less than the temporal dither applied to color plane determined to have the highest accumulated dither visibility score.

5. The apparatus of claim 4, wherein the temporal dither applied to the color plane determined to have the highest accumulated dither visibility score is a 3-bit temporal dither, and the temporal dither applied to the color plane determined to have the second-highest accumulated dither visibility score is a 1-bit temporal dither.

6. The apparatus of claim 1, wherein the processor is configured to apply temporal dither to only the color plane determined to have the highest accumulated dither visibility score.

7. The apparatus of claim 1, wherein the dither visibility function is stored as a look-up table (LUT).

8. The apparatus of claim 1, wherein the temporal dither includes a Floyd-Steinberg dither.

9. The apparatus of claim 1, wherein the plurality of color planes includes at least two color planes selected from the group consisting of a red color plane, a green color plane, and a blue color plane.

10. The apparatus of claim 1, wherein the plurality of color planes includes a first color plane configured to display a first hue of a color and a second color plane configured to display a second hue of the color, the first hue different from the second hue.

11. The apparatus of claim 1, wherein a color in the color space of the display device represents:

tone, grayscale, hue, chroma, saturation, brightness, lightness, luminance, correlated color temperature, dominant wavelength, or a coordinate in the color space.

12. The apparatus of claim 1, wherein the display device has a frame refresh rate less than 60 Hz.

13. The apparatus of claim 1, wherein the display device is a reflective display device.

14. The apparatus of claim 1, wherein each display pixel includes at least three subpixels.

15. The apparatus of claim 14, wherein each subpixel includes a movable mirror element.

16. The apparatus of claim 15, wherein the movable mirror elements of two different subpixels in each pixel have different reflective areas.

17. The apparatus of claim 14, wherein each subpixel is configured to display two bit color in the color space associated with the display device.

18. The apparatus of claim 1, further comprising a memory device that is configured to communicate with the processor.

19. The apparatus of claim 18, further comprising a driver circuit configured to send at least one signal to the display device.

20. The apparatus of claim 19, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

21. The apparatus of claim 1, further comprising an image source module configured to send the image data to the processor.

22. The apparatus of claim 21, wherein the image source module includes at least one of a receiver, transceiver, and transmitter.

23. The apparatus of claim 1, further comprising an input device configured to receive input data and to communicate the input data to the processor.

24. An apparatus comprising:

means for displaying image data including a plurality of image pixels, the displaying means including a plurality of display pixels configured to display a plurality of colors in a color space associated with the displaying means; and

means for processing the image data for display by the displaying means, the processing means configured for;

mapping the image data to the plurality of display pixels to provide data associated with each color plane in the color space associated with the displaying means, the color plane data including a color value for each display pixel in the displaying means;

for each color plane;

identifying display pixels having spatial frequencies below a threshold;

for each of the identified display pixels, calculating a dither visibility score based at least in part on comparison of the color value for the display pixel and a dither visibility function for the color plane, and

determining an accumulated dither visibility score for the color plane; and

applying temporal dither to a subset of the plurality of color planes based on the determined accumulated dither visibility scores.

25. The apparatus of claim 24, wherein the means for displaying image data includes a display device, or the means for processing includes a processor configured to communicate with the display device.

26. The apparatus of claim 24, wherein the processing means includes an accumulator.

27. The apparatus of claim 24, wherein the processing means includes a comparator.

28. A method for adaptively applying temporal dithering to display an input image having reduced dither visibility on a display device having a plurality of display pixels, each display pixel configured to display a plurality of colors in a color space associated with the display device, the method comprising:

mapping the input image to the plurality of display pixels to provide data associated with each color plane in the color space associated with the display device, the color plane data including a color value for each display pixel in the display device;

for each color plane;

identifying display pixels having spatial frequencies below a threshold;

calculating a dither visibility score for each of the identified pixels, wherein the dither visibility score is based at least in part on comparison of the color value for the display pixel and a dither visibility function for the color plane; and

determining an accumulated dither visibility score for the color plane; and

applying temporal dither to a subset of the plurality of color planes based on the determined accumulated dither visibility scores,

wherein the method is performed in its entirety by a physical computing device.

29. The method of claim 28, further comprising applying temporal dither to the color plane determined to have the highest accumulated dither visibility score.

30. The method of claim 29, further comprising applying temporal dither to the color plane determined to have the second-highest accumulated dither visibility score.

31. The method of claim 30, wherein the temporal dither applied to color plane determined to have the second-highest accumulated dither visibility score is lower than the temporal dither applied to color plane determined to have the highest accumulated dither visibility score.

32. A non-transitory computer storage medium comprising instructions that when executed by a processor cause the processor to perform a method for adaptively applying temporal dithering to display an input image having reduced dither visibility on a display device having a plurality of display pixels, each display pixel configured to display a plurality of colors in a color space associated with the display device, the method comprising:

mapping the input image to the plurality of display pixels to provide data associated with each color plane in the color space associated with the display device, the color plane data including a color value for each display pixel in the display device;

for each color plane;

identifying display pixels having spatial frequencies below a threshold;

calculating a dither visibility score for each of the identified pixels, wherein the dither visibility score is based at least in part on comparison of the color value for the display pixel and a dither visibility function for the color plane, and

determining an accumulated dither visibility score for the color plane; and

applying temporal dither to a subset of the plurality of color planes based on the determined accumulated dither visibility scores.

33. The non-transitory computer storage medium of claim 32, wherein the method further comprises applying temporal dither to the color plane determined to have the highest accumulated dither visibility score.

34. The non-transitory computer storage medium of claim 33, further comprising applying temporal dither to the color plane determined to have the second-highest accumulated dither visibility score.

35. The non-transitory computer storage medium of claim 34, wherein the temporal dither applied to color plane determined to have the second-highest accumulated dither visibility score is lower than the temporal dither applied to color plane determined to have the highest accumulated dither visibility score.