METHOD AND APPARATUS FOR HALFTONING PROCESS

摘要

An original binary image is converted to a weighted multi-valued image by a pixel converter. The original binary image is converted in such a manner that its pixels are reversed and shifted upward by one dot by a shift-up/reverse circuit to form an upward shifted reverse image, they are reversed and shifted downward by one dot by a shift-down/reverse circuit to form a downward shifted reverse image, they are reversed and shifted to the right by one dot by a shift-right/reverse circuit to form a rightward shifted reverse image, and they are reversed and shifted to the left by one dot by a shift-left/reverse circuit to form a leftward shifted reverse image. A halftoning circuit processes the shifted reverse images by subtraction to synthesize a halftone image.