Patent ID: 7920145

Claim:
A control method of controlling an image processing apparatus, for converting (n+m)-bit monochromatic image data represented by a single channel into n-bit color display image data represented by at least three channels, based on predetermined correlations between the (n+m)-bit monochromatic image data and the n-bit color display image data, wherein numeral “n” indicates a positive integer not less than 8, and numeral “m” indicates a positive integer not less than 2, the control method comprising: operating the image processing apparatus to perform: acquiring luminance information corresponding to each of monochrome signal values represented by the (n+m)-bit monochromatic image data; acquiring chromaticity information corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; determining each combination of plural-channel color signal values represented by the n-bit color display image data, based on the luminance information and the chromaticity information, so that each combination of the plural-channel color signal values corresponds to each of the monochrome signal values; establishing the predetermined correlations between the (n+m)-bit monochromatic image data and the n-bit color display image data, so that each combination of the plural-channel color signal values and each of the monochrome signal values are correlated with each other; selecting a plurality of candidate color display image data having signal values different from each other, with respect to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; and calculating a luminance and a chromaticity with respect to each of the plurality of candidate color display image data; wherein said acquiring of luminance information includes: a luminance determining process for determining a target luminance corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; wherein said acquiring of chromaticity information includes: a chromaticity determining process for determining a target chromaticity corresponding to each of the monochrome signal values represented by the (n+m)-bit monochromatic image data; and wherein, in said determining, signal values of color display image data are determined, based on a contrast between each luminance of the plurality of candidate color display image data calculated in said calculating and the target luminance, and another contrast between each chromaticity of the plurality of candidate color display image data calculated in said calculating and the target chromaticity.