METHOD AND APPARATUS FOR HALFTONING AND INVERSE HALFTONING AND THE TRANSMISSION OF SUCH IMAGES

摘要

A method for obtaining the inverse halftone or gray scaleimage of a halftone image is disclosed in which the halftone imagecan be comprised of clustered dots or dispersed dots, and it is notnecessary to have knowledge of the screening methods or parameter.This method involves adaptive run-length filtering over at leastone of rows and colums and diagonals of said halftones. A methodfor transmitting and receiving a gray scale image in a compressedand decompressed manner, respectively, is also disclosed for efficientfacsimile transmission of images. This method involves transmittinga local mean continuous tone image and an error image.