Method of generating a threshold matrix for producing a color separation, the matrix having a varied intensity distribution, method of reproducing a color image using the threshold matrix, apparatus for producing the color separation, and the threshold matrix

摘要

Threshold matrixes for a C-separation and an M-separation of main colors are used to convert a continuous-tone image subjected to color separation into dot patterns for the C-separation and the M-separation. The dot patterns are binary images in which no screen ruling or screen angle is defined. Then, a color image is reproduced by overlaying the dot patterns for the C-separation and the M-separation. When the dot patterns for the C-separation and the M-separation are converted into patterns in the frequency domain, main frequency components obtained by the conversion have a substantially-constant predetermined pattern frequency for all angles, and the intensity distribution of the main frequency components is varied based on the C-separation and the M-separation.