Device and method for color reduction with dithering

1. A method for driving a display panel including a plurality of pixels, comprising:

receiving first m-bit image data for a plurality of pixels, where m is an integer ≥3;

receiving addresses for the plurality of pixels, the addresses referring to a co-ordinate system defined for the display panel;

selecting n-bit dither values from elements of a dither table respectively corresponding to the addresses, where n is an integer from 2 to m;

generating second image data by performing dithering on the first m-bit image data using the n-bit dither values; and

driving a plurality of source lines of the display panel using the second image data.

2. The method according to claim 1 , wherein a frequency distribution of values of the elements of the dither table is uneven.

3. The method according to claim 1 , wherein the display panel comprises a plurality of pixel columns each comprising multiple pixels arrayed in a first direction in which source lines extend, and wherein generating the second image data comprises:

generating second image data corresponding to first pixels of a first pixel column of the plurality of pixel columns using n-bit dither values selected from elements in a first column of the dither table respectively corresponding to addresses of the first pixels; and

generating second image data corresponding to second pixels of a second pixel column adjacent to the first pixel column in a second direction perpendicular to the first direction using n-bit dither values selected from elements in a second column of the dither table respectively corresponding to addresses of the second pixels.

4. The method of claim 3 , wherein the elements of the first column of the dither table belong to a first half of elements of the dither table having smaller values, and

wherein the elements of the second column of the dither table belong to a second half of the elements of dither table having larger values.

5. The method of claim 3 , wherein generating the second image data comprises:

generating second image data corresponding to third pixels belonging to a third pixel column adjacent to the first pixel column in a third direction opposite to the second direction, the n-bit dither values selected from elements in a third column of the dither table respectively corresponding to addresses of the third pixels; and

generating second image data corresponding to fourth pixels belonging to a fourth pixel column adjacent to the second pixel column in the second direction, the n-bit dither values selected from elements in a fourth column of the dither table respectively corresponding to addresses of the fourth pixels,

wherein the elements of the third column of the dither table belong to a first half of the elements of the dither table having smaller values, and

wherein the elements of the fourth column of the dither table belong to a second half of the elements of the dither table having larger values.

6. The method according to claim 1 , wherein values of the elements of the dither table are determined so that there exist integers p 1 and p 2 , having values from 0 to 2 n −1, for which a number N(p 1 ) of elements having a value p 1 is different than a number N(p 2 ) of elements having a value p 2 .

7. The method according to claim 1 , wherein n is equal to m, and wherein:

the dither table is generated so that a number of elements of 2 m elements of the dither table having a value f(p) are equal to or larger than 2 m −p for p<(2 m −1)/2, and a number of elements of 2 m elements of the dither table having the value f(p) are equal to or larger than 2 m −p−1 for p>(2 m −1)/2, where f(p) is a desired brightness of a graylevel of a subpixel of p indicated by the first m-bit image data, in an image displayed on the display panel.

8. The method according to claim 1 , further comprising generating the first m-bit image data by performing a gamma correction on input image data.

9. The method according to claim 1 , wherein the second image data is generated as binary image data representing each subpixel graylevel of the plurality of pixels as a first value or a second value, and further comprising driving the display panel using the binary image data.

10. A method for driving a display panel including a plurality of pixels each comprising two or more subpixels, comprising:

generating m-bit corrected image data by performing a gamma correction on input image data, m being an integer≥3;

selecting n-bit dither values from elements of a dither table respectively corresponding to addresses of the plurality of pixels, the addresses referring to a co-ordinate system defined for the display panel, where n is an integer from 2 to m;

generating binary image data representing each graylevel of the subpixels of the plurality of pixels as a first value or a second value, by performing dithering on the corrected image data with n-bit dither values; and

driving the display panel using the binary image data.

11. The method of claim 10 , wherein a frequency distribution of values of the elements of the dither table is uneven.

12. The method of claim 10 , wherein the display panel comprises a plurality of pixel columns each comprising multiple pixels arrayed in a first direction in which source lines extend, and wherein generating the binary image data comprises:

generating binary image data corresponding to first pixels of a first pixel column of the plurality of pixel columns using the n-bit dither values selected from elements in a first column of the dither table respectively corresponding to addresses of the first pixels; and

generating binary image data corresponding to second pixels of a second pixel column that is adjacent to the first pixel column and in a second direction perpendicular to the first direction, using the n-bit dither values selected from elements in a second column of the dither table respectively corresponding to addresses of the second pixels.

13. The method of claim 12 , wherein the elements of the first column of the dither table belong to a first half of the elements of the dither table having smaller values, and

wherein the elements of the second column of the dither table belong to a second half of the elements of the dither table having larger values.

14. The method of claim 12 , wherein generating the binary image data comprises:

generating binary image data corresponding to third pixels of a third pixel column that is adjacent to the first pixel column and in a third direction opposite to the second direction, the n-bit dither values selected from elements in a third column of the dither table respectively corresponding to addresses of the third pixels; and

generating binary image data corresponding to fourth pixels of a fourth pixel column that is adjacent to the second pixel column in the second direction, the n-bit dither values selected from elements in a fourth column of the dither table respectively corresponding to addresses of the fourth pixels,

wherein the elements of the third column of the dither table belong to a first half of the elements of the dither table having smaller values, and

wherein the elements of the fourth column of the dither table belong to a second half of the elements of the dither table having larger values.

15. A display panel driver for driving a display panel including a plurality of pixels, comprising:

a dithering section configured to:

receive first m-bit image data, wherein m is an integer ≥3,

receive addresses for a plurality of pixels, the addresses referring to a co-ordinate system defined for the display panel,

select n-bit dither values from elements of a dither table respectively corresponding to the addresses, where n is an integer from 2 to m, and

generate second image data for the plurality of pixels by performing dithering on the first m-bit image data with the n-bit dither values; and

a driver circuit configured to drive a plurality of source lines of the display panel using the second image data.

16. The display panel driver of claim 15 , wherein a frequency distribution of values of the elements of the dither table is uneven.

17. The display panel driver of claim 15 , wherein the display panel comprises a plurality of pixel columns each comprising multiple pixels arrayed in a first direction in which source lines extend,

wherein the dithering section is further configured to:

generate second image data corresponding to first pixels belonging to a first pixel column of the plurality of pixel columns using n-bit dither values selected from elements in a first column of the dither table respectively corresponding to addresses of the first pixels; and

generate second image data corresponding to second pixels belonging to a second pixel column adjacent to the first pixel column in a second direction perpendicular to the first direction using n-bit dither values selected from elements in a second column of the dither table respectively corresponding to addresses of the second pixels.

18. The display panel driver of claim 17 , wherein the elements of the first column of the dither table belong to a first half of the elements of the dither table having smaller values, and

wherein the elements of the second column of the dither table belong to a second half of the elements of the dither table having larger values.

19. The display panel driver of claim 17 , wherein the dithering section is further configured to:

generate second image data corresponding to third pixels belonging to a third pixel column adjacent to the first pixel column in a third direction opposite to the second direction, the n-bit dither values selected from elements in a third column of the dither table in response to addresses of the third pixels; and

generate second image data corresponding to fourth pixels belonging to a fourth pixel column adjacent to the second pixel column in the second direction, the n-bit dither values selected from elements in a fourth column of the dither table respectively corresponding to addresses of the fourth pixels,

wherein the elements of the third column of the dither table belong to a first half of the elements of the dither table having smaller values, and

wherein the elements of the fourth column of the dither table belong to a second half of the elements of the dither table having larger values.

20. The display panel driver of claim 15 , wherein values of the elements of the dither table are determined so that there exist integers p 1 and p 2 , having values from 0 to 2 n −1, for which a number N(p 1 ) of elements of the dither table having the value p 1 is different from a number N(p 2 ) of elements of the dither table having the value p 2 .