Image data processor

Abstract

An image data processor for processing image data input with gray scale information corresponding to pixels in response to the number of divided-per-pixel gray scale levels that can be expressed by an image reproducing apparatus, the processor including a quantization portion for dividing gray scale values corresponding to the pixels of input image data by a comparison reference value set to about a gray scale between gray scale levels in which the image reproducing apparatus can express a pixel, and separately outputting the quotients and remainders of the division, a dithering portion for comparing the element values in a set dithering matrix with the remainder values at corresponding comparison positions and outputting the results of the comparison as binary bits, and a mixer for adding the quotients output by the quantization portion to the binary bits output by the dithering portion and outputting the sum to the image reproducing apparatus. The image data processor allows the image reproducing apparatus, capable of expressing a pixel in only a few gray scale levels, to reproduce an image having a gray scale similar to that of the original image data without greatly degrading the resolution of the image.