JPS6419873A - Image processing system - Google Patents

Abstract

PURPOSE:To satisfy both of gradation and resolution and to prevent a moire from generating in the case of a network-point original by providing a means to detect the characteristic of an inputted image and successively changing a binarizing processing system according to the detected characteristic value. CONSTITUTION:Inputted multi-value image data are inputted to an inputted value correcting circuit and a picture tone discriminating circuit. In the picture tone discriminating circuit, edge quantity is calculated by using a differential filter, etc. In the inputted value correcting circuit, the correction of the inputted value is executed by corrected data calculated in a corrected value operating circuit. In a threshold generating circuit, a dither threshold is generated in accordance with the edge quantity. In a binarization circuit, the corrected inputted data are quantized by using this threshold. A quantized error at such a time is computed by an error operating circuit and stored to a line buffer for error. In the corrected value operating circuit, the corrected value added and substracted in accordance with the edge quantity is outputted. The picture tone discriminating circuit is composed of an edge extracting part by a 3X3 matrix operation and an edge quantity operating part.