Image processing method

摘要

An image processing method is disclosed wherein an image is divided into a plurality of blocks. Each block comprises a plurality of picture elements which are sorted into a first group consisting of picture elements of densities not lower than a reference density and a second group consisting of picture elements of densities lower than the reference density. A representative density of picture elements of the first group and the second group in each block is obtained. An image discrimination is effected in accordance with the representative densities and then a determination of a threshold value is effected in accordance with the representative densities and the result of the image discrimination. The image discrimination and determination of threshold values are conducted by using histograms made out from the representative density of picture elements of the first group in each block and the representative density of picture elements of the second group in each block. Image information is then converted into binary signals according to the threshold value.