System and method for dithering video data

• US 20090303248A1
• Filed: 06/06/2008
• Published: 12/10/2009
• Est. Priority Date: 06/06/2008
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Ng, Sunny Yat-san
• Granted Patent: US 9,024,964 B2
• Time in Patent Office: Days
• US Class Current: 345/596
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2340/0428 Gradation resolution change
• CPC Class Codes: G09G 3/2055 the pattern being varied in time
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A novel method for driving a display device includes the steps of receiving video data of a first type, converting the video data to data of a second type, dithering the data of the second type to form dithered pixel data, and outputting the dithered pixel data. The step of converting the video data to data of a second type includes inserting dither bits indicative of a particular dithering scheme into the data of the second type. An example display driver circuit includes an input for receiving video data, a data converter coupled to receive the video data and operative to convert the video data into pixel data to be written to pixels of a display, and a ditherer operative to receive the pixel data and to dither the pixel data to generate dithered pixel data. The video data is data of a first type, and the pixel data is data of a second type, different from the first type. In the disclosed example, the first type of data includes a binary data word, and the second type of data includes a compound data word. The compound data word includes a first set of binary weighted bits, a second set of arbitrarily weighted bits, and dither bits.

Claims

1. A display driver circuit, said circuit including:

an input for receiving video data;

a data converter coupled to receive said video data and to convert said video data into pixel data to be written to pixels of a display; and

a ditherer operative to receive said pixel data and to dither said pixel data to generate dithered pixel data.

2. A display driver circuit according to claim 1, wherein:

said video data is data of a first type; and

said pixel data is data of a second type different from said first type.

3. A display driver circuit according to claim 2, wherein said first type of data includes a binary data word.

4. A display driver circuit according to claim 2, wherein said second type of data includes a compound data word.

5. A display driver circuit according to claim 4, wherein:

said compound data word includes a first set of binary weighted bits, said first set of bits including at least one bit; and

said compound data word includes a second set of arbitrarily weighted bits, said second set of bits including at least one bit.

6. A display driver circuit according to claim 4, wherein:

said compound data word includes a first set of binary weighted bits, said first set of bits including at least one bit; and

said compound data word includes a second set of equally weighted bits, said second set of bits including at least one bit.

7. A display driver circuit according to claim 1, wherein:

said video data is capable of defining a first number of values; and

said pixel data is capable of defining a second number of values, said second number of values being greater than said first number of values.

8. A display driver circuit according to claim 1, wherein:

said video data includes data words having a first number of bits; and

said pixel data includes data words having a second number of bits, said second number of bits being greater than said first number of bits.

9. A display driver circuit according to claim 1, wherein:

said video data is binary-weighted video data; and

said pixel data includes data words having a group of equally weighted bits.

10. A display driver circuit according to claim 9, wherein said data words of said pixel data further include a group of binary weighted bits.

11. A display driver circuit according to claim 1, wherein said ditherer performs a predetermined dithering function based on at least a portion of said pixel data.

12. A display driver circuit according to claim 1, wherein said data converter includes a look-up-table.

13. A method for driving a display device, said method comprising:

receiving video data of a first type;

converting said first type of video data to data of a second type;

dithering said data of said second type to form dithered pixel data; and

outputting said dithered pixel data.

14. A method according to claim 13, wherein said step of receiving said video data includes receiving a binary data word.

15. A method according to claim 13, wherein said first type of data is defined by a first data word, and said second type of data is defined by a second data word, said first data word having a least significant bit and said second data word having a least significant bit, said least significant bit of said second data word being less significant than said least significant bit of said first data word.

16. A method according to claim 13, wherein said step of converting said video data to said data of a second type includes converting said video data to said data of said second type via a lookup table.

17. A method according to claim 13, wherein said second type of data defines more values than said first type of data.

18. A method according to claim 17, wherein:

said video data includes a first data word defined by a first number of bits;

said second type of data includes a second data word defined by a second number of bits, and

said second number of bits is greater than said first number of bits.

19. A method according to claim 18, wherein:

said step of converting said first type of data to data of a second type includes adding a set of dither bits to each data word of said second type; and

said step of dithering said second type of data includes dithering said data word of said second type according to one of a plurality of predetermined dithering logic functions depending on the value of said dither bits.

20. A method according to claim 13, wherein said step of converting said video data to said second data type includes converting said video data to a compound data word.

21. A method according to claim 20, wherein said compound data word includes a first set of binary bits and a second set of arbitrarily weighted bits, said first set of binary bits and said second set of arbitrarily weighted bits each including at least one bit.

22. A method according to claim 21, wherein said arbitrarily weighted bits include a set of equally weighted bits.

23. A method for driving a display device, said method comprising:

providing a display with an array of individual pixels;

defining a group of said pixels of said display;

temporally dithering data to be written to each pixel of said group to generate a series of values to be asserted on each pixel of said group; and

changing the order of at least one of said series of values depending on the location of a pixel of said group upon which said reordered series of values is to be asserted.