Method and unit for binary processing in image processing unit and method and unit for recognizing characters

摘要

A binary processing method for a variable density image the method includes the steps of binary processing an image having variable density, according to which brightness of an image having variable density to be binary processed is given as 1/n (where n is an integer of 2 or above), and expansion processing and smoothening processing the image having the brightness of 1/n so that a threshold value image for binary processing is generated. A difference is obtained between the threshold value image and the variable density image to be binary processed, such that it is possible to carry out binary processing even for an image having a complex background or variance in brightness.