Method and apparatus for color space conversion using per-color selection of look-up table density

• US 7,940,982 B1
• Filed: 05/31/2007
• Issued: 05/10/2011
• Est. Priority Date: 05/31/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Zoran Corporation (Qualcomm, Inc.)
• Inventors: Shaick, Ben-Zion
• Primary Examiner(s): Do; Anh Hong
• Application Number:
  US11/809,562
• Time in Patent Office: 1,440 Days
• Field of Search: 382/162, 382/167, 382/246, 382/307, 382/308, 345/156, 345/158, 345/619, 345/629, 358/1.9, 358/1.15, 710/65, 711/168, 711/200, 712/34, 712/210, 365/230.05
• US Class Current: 382/162
• CPC Class Codes: H04N 1/46 Colour picture communication systems
• CPC Class Codes: H04N 1/6019 using look-up tables H04N1/6025 takes precedence
• CPC Class Codes: H04N 1/6058 Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut

Abstract

A method of performing color space conversion includes maintaining a data structure that has a plurality of dimensions and that contains a plurality of locations storing information in each of the dimensions. Each of the dimensions corresponds to a different one of a plurality of input color signal components. The number of locations which the data structure contains in a first one of the dimensions is different from the number of locations which the data structure contains in a second one of the dimensions. The method further includes inputting first data defined according to a first color space, and generating second data defined according to a second color space, by applying information contained in the data structure to the first data.

Claims

1. A method operating within one or more microprocessors of performing color space conversion, the method comprising:

maintaining a data structure that has a plurality of dimensions and that contains a plurality of locations storing information in each of the dimensions, each of the dimensions corresponding to a different one of a plurality of input color signal components, wherein the number of locations which the data structure contains in a first one of the dimensions is different from the number of locations which the data structure contains in a second one of the dimensions; and

inputting first data defined according to a first color space;

generating second data defined according to a second color space, by applying information contained in the data structure to the first data.

2. A method as recited in claim 1, wherein the data structure comprises a plurality of multi-dimensional look-up tables (LUTs), each corresponding to a different output color component.

3. A method as recited in claim 2, wherein each of the multi-dimensional LUTs includes a plurality of locations, each location containing an output color signal value for a particular combination of the plurality of input color signal components.

4. A method as recited in claim 3, wherein the plurality of multi-dimensional LUTs comprises three multi-dimensional look-up tables (LUTs), each corresponding to a different output color signal component, each of the multi-dimensional LUTs having a separate dimension for each of the plurality of input color signal components.

5. A method as recited in claim 4, wherein each of said multi-dimensional LUTs is a three-dimensional LUT.

6. An apparatus comprising:

an input device to receive first data defined according to a first color space;

a memory having stored therein a data structure that has a plurality of dimensions and that contains a plurality of locations storing information in each of the dimensions, each of the dimensions corresponding to a different one of a plurality of input color signal components, wherein the number of locations which the data structure contains in a first one of the dimensions is different from the number of locations which the data structure contains in a second one of the dimensions; and

a processor to generate second data defined according to a second color space, by applying information contained in the data structure to the first data.

7. An apparatus as recited in claim 6, wherein the apparatus is a digital camera.

8. An apparatus as recited in claim 6, wherein the data structure comprises a plurality of multi-dimensional look-up tables (LUTs), each corresponding to a different output color component.

9. An apparatus as recited in claim 8, wherein each of the multi-dimensional LUTs includes a plurality of locations, each location containing an output color signal value for a particular combination of the plurality of input color signal components.

10. An apparatus as recited in claim 9, wherein the plurality of multi-dimensional LUTs comprises three multi-dimensional look-up tables (LUTs), each corresponding to a different output color signal component, each of the multi-dimensional LUTs having a separate dimension for each of the plurality of input color signal components.

11. An apparatus as recited in claim 9, wherein each of said multi-dimensional LUTs is a three-dimensional LUT.

12. A digital camera comprising:

a set of optics;

an image sensor coupled to the optics;

an analog-to-digital converter to generate first data defined according to a first color space based on output of the image sensor;

a memory having stored therein a data structure that has a plurality of dimensions and that contains a plurality of locations storing information in each of the dimensions, each of the dimensions corresponding to a different one of a plurality of input color signal components, wherein the number of locations which the data structure contains in a first one of the dimensions is different from the number of locations which the data structure contains in a second one of the dimensions; and

a processor to generate second data defined according to a second color space, by applying information contained in the data structure to the first data.

13. A digital camera as recited in claim 12, wherein the data structure comprises a plurality of multi-dimensional look-up tables (LUTs), each corresponding to a different output color component.

14. A digital camera as recited in claim 13, wherein each of the multi-dimensional LUTs includes a plurality of locations, each location containing an output color signal value for a particular combination of the plurality of input color signal components.

15. A digital camera as recited in claim 14, wherein the plurality of multi-dimensional LUTs comprises three multi-dimensional look-up tables (LUTs), each corresponding to a different output color signal component, each of the multi-dimensional LUTs having a separate dimension for each of the plurality of input color signal components.

16. A digital camera as recited in claim 15, wherein each of said multi-dimensional LUTs is a three-dimensional LUT.

17. An apparatus comprising:

logic to maintain in a memory a data structure that has a plurality of dimensions and that contains a plurality of locations storing information in each of the dimensions, each of the dimensions corresponding to a different one of a plurality of input color signal components, wherein the number of locations which the data structure contains in a first one of the dimensions is different from the number of locations which the data structure contains in a second one of the dimensions; and

an input to receive first data defined according to a first color space;

logic to generate second data defined according to a second color space, by applying information contained in the data structure to the first data.

18. An apparatus as recited in claim 17, wherein the data structure comprises a plurality of multi-dimensional look-up tables (LUTs), each corresponding to a different output color component.

19. An apparatus as recited in claim 18, wherein each of the multi-dimensional LUTs includes a plurality of locations, each location containing an output color signal value for a particular combination of the plurality of input color signal components.

20. An apparatus as recited in claim 19, wherein the plurality of multi-dimensional LUTs comprises three multi-dimensional look-up tables (LUTs), each corresponding to a different output color signal component, each of the multi-dimensional LUTs having a separate dimension for each of the plurality of input color signal components.

21. An apparatus as recited in claim 20, wherein each of said multi-dimensional LUTs is a three-dimensional LUT.