System and method for dithering video data

• US 9,024,964 B2
• Filed: 06/06/2008
• Issued: 05/05/2015
• 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
• Primary Examiner(s): Thompson, James A
• Application Number:
  US12/157,190
• Publication Number:
  US 20090303248A1
• Time in Patent Office: 2,524 Days
• Field of Search: 345204-215, 345690-693, 345/98, 345/100, 345/600, 345/603, 345/596
• 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, said video data including data words having a first number of bits, each data word having a value defining an intensity level to be displayed by an individual pixel;

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, said pixel data including data words having a second number of bits, said second number of bits being greater than said first number of bits, each data word having a value defining an intensity level to be displayed by an individual pixel; and

a ditherer operative to receive said pixel data and to dither said pixel data to generate temporally dithered pixel data, said dithered pixel data including a greater number of bits than said video data.

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

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

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

3. 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.

4. 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.

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

6. A display driver circuit according to claim 1, wherein said ditherer is further operative to generate a series of values to be asserted on corresponding pixels of said display, the order of said values of each said series of values varying depending on the location of said corresponding pixel upon which said series of values is to be asserted.

7. 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.

8. A display driver circuit according to claim 7, wherein said first type of data includes a binary data word.

9. A display driver circuit according to claim 7, wherein said second type of data includes a compound data word.

10. A display driver circuit according to claim 9, 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.

11. A display driver circuit according to claim 10, wherein said second set of arbitrarily weighted bits includes a set of equally weighted bits.

12. 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 different from said first type;

temporally dithering said data of said second type to form dithered pixel data, said dithered pixel data including a greater number of bits than said video data; and

outputting said dithered pixel data; and

wherein

said first type of data is defined by a first data word, said second type of data is defined by a second data word, and said dithered pixel data is defined by said 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, said first data word and said second data word each having a value defining an intensity level to be displayed by an individual pixel.

13. A method according to claim 12, wherein said step of receiving said video data includes receiving a binary data word.

14. A method according to claim 12, 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.

15. A method according to claim 12, wherein said second type of data defines more values than said first type of data.

16. A method according to claim 15, wherein:

said first data word is defined by a first number of bits;

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

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

17. A method according to claim 12, wherein said step of converting said first type of video data to said second type includes converting a data word of said video data to a compound data word.

18. A method according to claim 17, wherein:

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

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

19. A method according to claim 17, 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.

20. A method according to claim 19, wherein said arbitrarily weighted bits include a set of equally weighted bits.

21. 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; and

wherein

said step of temporally dithering data includes

receiving digital video data of a first type, said video data of said first type including data words having values defining intensity levels to be displayed by individual pixels,

converting said digital video data of said first type to data of a second type, said data of said second type including data words having values defining intensity levels to be displayed on individual pixels and being capable of defining more values than said data words of said data of said first type, and

dithering said data of said second type to generate said series of values;

said data of said second type includes a compound data word for each pixel of said group; and

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 data words of said data of said second type each include a greater number of bits than said data words of said digital video data.