Patent ID: 6707577
Filing Date: 2004-03-16
Classification: H04N

Abstract:
A gray scale image processing method which converts an input image, each pixel of which has a value between 0 and N, to an output image, each pixel of which is represented by a gray scale value of A levels, comprising:a generation step of generating B reference images, in each of which each pixel is represented by a gray scale value of said A levels, from B elementary images, in each of which all pixels have the same value between 0 and N, using one or more different error distribution matrixes according to said A levels; a selection step of selecting one of said B reference images based on a pixel value f(x,y) of said input image at coordinates (x,y); and an output step of outputting a pixel value represented by a gray scale value of said A levels of said selected one of said B reference images at a position corresponding to said coordinates (x,y).