A Subjectively Adapted Image Communication System

An interactive image communication system is described transmitting image information stored in a central database over low-bitrate channels. To shorten the transmission time, a data compression technique is applied in combination with a progressive image transmission procedure. Furthermore, human interaction is implemented in order to select specific areas for picture buildup or to reject additional image sharpening completely. The mean transmission time for each picture is essentially reduced if the transmission parameters of the investigated system are adapted to the visual threshold performance of the human eye. The adaptation is realized by means of the given classification algorithm. For a set of portrait pictures, more than 95 percent of the transmission time can be gained by this adaptation in comparison with PCM transmission.