HALFTONE IMAGE TRANSMISSION METHOD

A method for transmitting a halftone image using the dither method is provided. In accordance with the present invention, an original image to be transmitted is divided into a plurality of regions corresponding in pattern and shape to the dither matrix used. And, each of the regions thus divided is further subdivided into a plurality of subregions of predetermined shape and then the average value of density for each of the regions is calculated. This average value is then compared with each of the thresholds of the corresponding group in the dither matrix to determine the location of a maximum threshold among those thresholds which are equal to or less than (or less than) the average value to determine an address for each of the regions. Then, such a string of addresses is subjected to a predetermined coding for compression of data to be transmitted. Upon receipt of such data, the process described above is basically reversed to reconstruct a dither-processed halftone image.