| 摘要 |
PURPOSE:To obtain a pattern with fidelity to a picture signal and to attain excellent color reproduction by using a dot matrix threshold pattern where the order of pattern arrangement is opposite to a dot matrix threshold pattern of each color used to produce a black intermediate tone picture. CONSTITUTION:A picture signal obtained by a picture input device 1 is subject to color limpid correction and inputted to a background color elimination device 3 via a masking processing circuit 2 generating yellow, cyan and magenta color signals. Then the overlapped three colors are replaced by a gray signal, the subtraction processing corresponding to each color signal is applied and signals as four color signals of yellow Y', magenta M', cyan C' and gray K' are subject to dither processing by a dither processing circuit 4 and the result is outputted to an output device 5. The circuit 4 uses a dot matrix threshold pattern with entirely opposite arrangement order for the dot matrix threshold pattern M1 for three colors of yellow, magenta and cyan and a gray dot matrix threshold pattern M2 so as to reduce the overlap among the gray dot and the other three color dots and the change in the area rate of the dot of each color due to background color elimination is decreased.
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