IMAGE TRANSMISSION METHOD AND APPARATUS

IMAGE TRANSMISSION METHOD AND APPARATUS The gray-scale information in a scanned image is presented on a bi-level display medium illustratively using the known ordered dither technique. In particular, the image is scanned in a matrix of picture elements, each corresponding to a different cell of the display medium. A dither threshold value is assigned to each picture element from a predetermined dither matrix. If the intensity of any given picture element is greater than the dither threshold value assigned thereto, the corresponding display cell is turned on. Otherwise, it is maintained off. The state of the cell corresponding to each picture element is represented by a dithered image bit. The bandwidth and/or time required to transmit the image to a remote display medium is substantially reduced by assembling in respective groups dithered image bits which correspond to picture elements having equal (or substantially equal) assigned dither threshold values. The resultant bit stream is then encoded for transmission via, for example, standard run-length encoding techniques.