JPS6419872A - Picture processing system - Google Patents

Abstract

PURPOSE:To satisfy both of a gradation and a resolution and to prevent a moire generating in the case of a dot original by having a means to discriminate the binarization systems of two types and the picture tone of an inputted image and selecting the one of the binarization systems of the two types according to the discriminated picture tone. CONSTITUTION:In an inputted value correcting circuit, the inputted value is corrected by a value to correct the error of a circumferential picture element computed computed by a corrected value computing circuit. A picture tone discriminating circuit is composed of a line buffer, an adder and a multiplier and discriminates an edge extraction and the picture tone. When a decision is executed as a character and a dot image, 1 is outputted and when the desicion is a photograph image, 0 is outputted. A threshold generating circuit outputs a threshold when data from the picture tone discriminating circuit is 1 and generates a threshold to two-dimensionally change (dither pattern data) when the data is 0. A binarization circuit can be realized by using a comparator. Namely, the corrected input value and the threshold are compared, 1 is outputted when the inputted value is large and 0 is outputted when it is small.