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Control apparatus, multidimensional color correction method and non-transitory computer-readable storage medium storing multidimensional color correction program

  • US 9,894,248 B2
  • Filed: 01/03/2017
  • Issued: 02/13/2018
  • Est. Priority Date: 01/07/2016
  • Status: Active Grant
First Claim
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1. A control apparatus for controlling a user printing device equipped with a print engine that forms images by using at least three primary colors which are different in hue from each other, the control apparatus comprising:

  • a raster-image processor that performs multidimensional color correction and color conversion on image data created from a print job, the multidimensional color correction being a process to correct colors to be output by the user printing device into colors to be output by a predetermined standard printing device, by using a multidimensional LUT (look-up table) which associates input color values of three or more primary colors with corresponding output color values, the color conversion being a process to convert colors to be output by the standard printing device into target colors, by using a printer profile for the standard printing device and a target profile; and

    a control unit that controls the raster-image processor, and includesa table creation section that creates the multidimensional LUT including a first LUT and a second LUT, the first LUT including output color values which are indexed by the input color values and are to be obtained by the multidimensional color correction performed on the input color values without a specific process, the specific process being a process to preserve values of complementary color components of secondary colors before and after the multidimensional color correction, the second LUT including output color values which are indexed by the input color values and are to be obtained by the multidimensional color correction performed on the input color values with the specific process, anda correction control section thatobtains color values of fully saturated secondary colors of the user printing device, the standard printing device and the target colors, by referring to the multidimensional LUT, the printer profile for the standard printing device and the target profile,calculates chromas of the fully saturated secondary colors of the user printing device, the standard printing device and the target colors from the color values obtained, to compare the chromas with each other for each of the fully saturated secondary colors, andon judging that the chroma of one of the fully saturated secondary colors of the user printing device is greater than the chroma of the one of the fully saturated secondary colors of the standard printing device, gives the raster-image processor an instruction to perform the multidimensional color correction while specifying use of the first LUT or the second LUT on a basis of the chromas of the one of the fully saturated secondary colors, so as toinstruct the raster-image processor to perform the multidimensional color correction while specifying use of the second LUT, on judging that the chroma of the one of the fully saturated secondary colors of the target colors is greater than the chroma of the one of the fully saturated secondary colors of the user printing device, andinstruct the raster-image processor to perform the multidimensional color correction while specifying use of the first LUT, on judging that the chroma of the one of the fully saturated secondary colors of the target colors is smaller than the chroma of the one of the fully saturated secondary colors of the standard printing device, andoutputs print image data on which the raster-image processor performed the multidimensional color correction and the color conversion, to the print engine and gives the print engine a print instruction.

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