Claims
- 1. A method of color conversion comprising:
providing a first color domain input signal set having plural input signals; sorting the input signals of the first color domain input signal set according to signal intensity; designing and generating plural 1-D look-up table sets for color polyhedrons; selecting a set of look-up tables for use with a specific color polyhedron, wherein said selecting is a function of a section of the polyhedron determined as a function of the input signal set; looking up values in the look-up table set as a function of the input signal set; generating weights as a function of the sorted signal intensities; and interpolating the output from the selected look-up tables as a function of the selected look-up table and the generated weights to produce a color domain signal set which is converted to a desired color domain signal set.
- 2. The method of claim 1 which includes compensating for hue shifts in the first color domain, including sorting the input signal sets into color domain components, Vl, Vm, Vs, where Vl≧Vm≧Vs; generating an order signal, designing and generating a 1-D look-up table for the color domain, generating weights w1 and w2 as a function of Vl, Vm, Vs, selecting a look-up table as a function of the sorted components and the order signal, and interpolating the color domain components with the weights and selected look-up table to provide a signal set for a desired color domain.
- 3. The method of claim 2 wherein said compensating for hue shifts in the first color domain includes inputting a RGB input signal; designing and generating CMY 1-D look-up tables; and interpolating to provide a CMY signal set.
- 4. The method of claim 2 wherein said compensating for the desired color domain includes inputting a CMY input signal and black generation; designing and generating CMYK 1-D look-up tables; and interpolating to provide a CMYK signal set.
- 5. The method of claim 4 wherein said designing and generating CMYK 1-D look-up tables includes specifying independent look-up tables for each primary color and each secondary color and black.
- 6. The method of claim 5 wherein said designing and generating CMYK 1-D look-up tables includes controlling hue angles.
- 7. The method of claim 5 wherein said designing and generating CMYK 1-D look-up tables includes controlling metric spacing of color ramps.
- 8. The method of claim 4 wherein said designing and generating CMY 1-D look-up tables includes specifying independent look-up tables for each primary color and each secondary color.
- 9. The method of claim 8 wherein said designing and generating CMY 1-D look-up tables includes controlling hue angles and metric spacing of color ramps.
- 10. The method of claim 2 wherein said compensating for the desired color domain includes inputting a CMY input signal; designing and generating CMY 1-D look-up tables; and interpolating to provide a RGB signal set.
- 11. The method of claim 1 wherein said processing the desired color domain signal set includes black generation.
- 12. The method of claim 11 wherein said providing a first color domain input signal set includes providing a RGB signal set, and which includes generating a final colorant signal set, including generating a CMYK signal set.
- 13. The method of claim 1 wherein said providing a first color domain input signal set includes providing a RGB signal set, and which includes generating a final colorant signal set, including generating a modified first color domain signal set which is a RGB signal set.
- 14. The method of claim 1 which includes processing the first color domain input signal set in a upper half hue straightening module wherein all colors are processed, including compensating for hue shifts, to generate a second color domain signal set; and processing the second color domain signal set in a lower half hue straightening module wherein colors between pure colors and black are processed, including compensating for hue shifts, to generate a final colorant signal set in the desired color domain.
- 15. The method of claim 14 wherein said processing the second color domain input signal includes sorting the input signals according to signal intensity; designing and generating 1-D look-up tables for color line segments; selecting a specific look-up table; generating weights as a function of the sorted signal intensities; and interpolating the input signals to generate the final colorant signal set.
- 16. The method of claim 14 wherein said compensating for hue shifts includes sorting signal sets into color domain components, Vl, Vm, Vs, where Vl≧Vm≧Vs; generating an order signal, designing and generating a 1-D look-up table for the color domain, generating weights w1 and w2 as a function of Vl, Vm, Vs, selecting a look-up table set as a function of the sorted components and the order signal, and interpolating the color domain components with the weights and selected look-up table set to provide another color domain signal set.
- 17. The method of claim 16 wherein said compensating for the first color domain includes inputting a RGB input signal; designing and generating CMY 1-D look-up tables; and interpolating to provide a CMY signal set.
- 18. The method of claim 17 wherein said compensating for the second color domain includes inputting a CMY input signal and black generation; designing and generating CMYK 1-D look-up tables; and interpolating to provide a CMYK signal set.
- 19. The method of claim 18 wherein said designing and generating CMYK 1-D look-up tables includes specifying independent look-up tables for each primary color and each secondary color and black.
- 20. The method of claim 19 wherein said designing and generating CMYK 1-D look-up tables includes controlling metric spacing of color ramps.
- 21. The method of claim 19 wherein said designing and generating CMYK 1-D look-up tables includes controlling hue angles.
- 22. The method of claim 16 wherein said compensating for the second color domain includes inputting a CMY input signal; designing and generating CMY 1-D look-up tables; and interpolating to provide a RGB signal set.
- 23. The method of claim 16 wherein said designing and generating CMY 1-D look-up tables includes specifying independent look-up tables from each primary color and each secondary color.
- 24. The method of claim 23 wherein said designing and generating CMY 1-D look-up tables includes controlling hue angles.
- 25. The method of claim 23 wherein said designing and generating CMY 1-D look-up tables includes controlling metric spacing of color ramps.
- 26. The method of claim 14 wherein said processing the second color domain signal set includes black generation.
- 27. The method of claim 26 wherein said providing a first color domain input signal set includes providing a RGB signal set, and wherein generating final colorant signal set includes generating a CMYK signal set.
- 28. The method of claim 14 wherein said providing a first color domain input signal set includes providing a RGB signal set, and wherein generating final colorant signal set includes generating a modified first color domain signal set which is a RGB signal set.
- 29. A method of color conversion comprising:
providing a RGB input signal set; processing the RGB input signal set in a upper half hue straightening module wherein colors are processed, including compensating for hue shifts, to generate a second color domain signal set; and processing the second color domain signal set in a lower half hue straightening and black generation module wherein all colors are processed, including compensating for hue shifts, to generate a final colorant signal set.
- 30. The method of claim 29 wherein said processing the RGB input signal includes sorting the input signals according to signal intensity; designing and generating 1-D look-up tables for color line segments; selecting a specific look-up table set; generating weights as a function of the sorted signal intensities; and interpolating the values from the look-up table set to generate a CMY signal set.
- 31. The method of claim 30 wherein said processing the CMY signal set includes sorting the input signals according to signal intensity; designing and generating 1-D look-up tables for color line segments and achromatic line segments; selecting a specific look-up table set; generating weights as a function of the sorted signal intensities; and interpolating the look-up table signals to generate a CMYK colorant signal set.
- 32. The method of claim 29 wherein said compensating for hue shifts includes sorting signal sets into color domain components, Vl, Vm, Vs, where Vl≧Vm≧Vs; generating an order signal, designing and generating a 1-D look-up table for the color domain, generating weights w1 and w2 as a function of Vl, Vm, Vs, selecting a look-up table as a function of the sorted components and the order signal, and interpolating the color domain components with the weights and selected look-up table to provide another color domain signal set.
- 33. The method of claim 32 wherein said compensating for the RGB signal set includes designing and generating second color domain 1-D look-up tables; and interpolating to provide the second color domain signal set.
- 34. The method of claim 33 wherein said compensating for the second color domain signal set includes black generation; designing and generating final color domain 1-D look-up tables; and interpolating to provide the final colorant signal set.
- 35. The method of claim 34 wherein said designing and generating the second color domain 1-D look-up tables and final 1-D look-up tables includes specifying independent look-up tables for each primary color and each secondary color and black.
- 36. The method of claim 30 wherein said designing and generating second color domain 1-D look-up tables and final 1-D look-up tables includes controlling hue angles.
- 37. The method of claim 30 wherein said designing and generating second color domain 1-D look-up tables and final 1-D look-up tables includes controlling metric spacing of color ramps.
- 38. The method of claim 29 which includes preprocessing an RGB input signal by inversion to generate a CMY input signal.
RELATED APPLICATIONS
[0001] This application is related to U.S. patent application Ser. No. 09/741,458, filed Dec. 19, 2000, for Black Generation Method for CMYK Color Printers Using Multiple Lookup Tables and Interpolation.
Provisional Applications (1)
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Number |
Date |
Country |
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60324862 |
Sep 2001 |
US |