Abstract: In a color converting device for converting input image data based on a plurality of first color components (the number of bits of each color component is k) into output image data based on plural of second color components by interpolation processing using a 3DLUT storing color correction values at grid points obtained by dividing a color space composed of the plurality of first color components, the distance of the grid points is 2n (where n is an integer smaller than k), the number Dn of grid points of the plurality of first color components is an integer satisfying 2m?1+1<Dn<2m+1+1 (where Dn?2m+1, and m=k?n), and input image data is converted into output image data by converting each color component data of the input image data according to the number of grid points, and performing interpolation processing by reading color correction values corresponding to the converted color components from the 3DLUT.

Abstract: An original is illuminated by a light source ? or a light source ?, and image data is obtained under these conditions. An absolute value of a difference between image data under these different conditions is compared to a threshold value, and it is judged whether or not a color-unmatch occurs. If the color-unmatch occurs, the color-unmatch is corrected in accordance with a plurality of image data read under different conditions.

Abstract: In a copier, a specific pattern being hardly recognizable by human eyes but recognizable by a recognizing means is added onto a color image to be printed on a recording medium in order to clearly indicate that the printed image is a copy image. RGB-color image data is converted by a post processing portion of an image processing unit into YMCK color image data. An additional color forming unit calculates color data YaMaCaKa of a specific pattern received from a specific pattern generating unit based on the RGB-color image data. A combining unit generates output Y′M′C′K′-color image data including the specific pattern color image data by combining YMCK color data with the specific pattern data of YaMaCaKa. An image output unit adds the specific pattern on the color image according to the Y′M′C′K′ color image data.

Abstract: A color image processing device includes color conversion means for outputting color adjusted signals having been chromatically adjusted in accordance with the input of separated color signals obtained from a scanner and a variable factor signal other than color signals. The color conversion means includes a memory device for discretely storing only the color adjusted signals that correspond to predetermined separated color signals and a predetermined variable factor signal, and color adjusting means for, when the inputted separated color signal or the inputted variable factor signal directly corresponds to none of the color adjusted signals stored in the memory means, outputting color adjusted signals having been interpolated in accordance with the known color adjusted signals found in a neighborhood of the inputted separated color signals and variable factor signal.