METHOD FOR BINARIZING PICTURE DATA AND ITS DEVICE

摘要

PROBLEM TO BE SOLVED: To binarize picture data without deteriorating picture quality. SOLUTION: Error dataΣep is read from an error memory 20 concerning a picture element P to be considered. An adder 22 adds error data to multi- valued picture data concerning the picture element P to be considered. A comparator 24 binarizes multi-valued picture data and outputs binary picture data. A subtractor 26 derives difference (e) between picture data before binarization and picture data after binarization. An error distributing window selecting circuit 32 outputs '1' as control data when the value of multi-valued picture data is '0'-'13' and also the value of picture data after binarization is '1' or when the value of multi-valued picture data is '242'-'255' and also the value of picture data after binarization is '0' and outputs '0' at the time of a case except them. An error distributing circuit 30 distributes error (e) to the eight picture elements A-H when the value of control data is '1' and to the four picture elements A and C-E at the time of '0'.