JPS6416658A - Color conditioning method - Google Patents

Abstract

PURPOSE:To enable color adjustment and color correction to be performed in a unified manner in conformity with the human sensation of color, by converting original color signals from an RGB space into an HLS space, then performing color adjustment and color correction through using lookup tables independently for H (hue), L (lightness) and S (saturation), and re-converting the adjusted or corrected color signals into the RGB space. CONSTITUTION:A manuscript 1 is subjected to color separation into red R, green G and blue B by a color scanner 2, then the resultant color signals are inputted to an RGB-to-HLS converting part 3, whereby the signals are converted to signals of hue H, lightness L and saturation S. The HLS signals are converted into signals N', L' and S' by lookup tables (LUT) 4 for exclusive use for each of H, L and S, and these signals are inputted to an HLS-to-RGB converting part 5, whereby the signals are converted into signals R', G' and B', which are used to directly drive a color printer 6 to print a hard copy 7. Thus, original color signals are converted from the RGB space into the HLS space, then color adjustment and color correction are performed by using the LUTs independently for each of H, L and S, and the adjusted or corrected color signals are a re-converted into the RGB space, whereby color conditioning based on color sensation can be performed without discrimination between color adjustment and color correction.