Spatial domain coding techniques for image sequences

Two spatial domain techniques for coding videotelephone images are described. These coders are considered as part of a class of coders which try to preserve the visually important features of the image by employing image analysis techniques and characteristics such as those of the human visual system. Since high sensitivity to image edges is one of the main features of the human eye an important property of two component and segmented image coders can be considered to be their different treatment of the image components, paying special attention to the edge component. It is possible, therefore, to restrict the distortion to the edge component and preserve the sharpness of the image. This is not the case with conventional coders, however, as the whole image is treated in a uniform way. To demonstrate the efficiency of the above coding algorithms comparisons have been made with the results of the conventional DCT coding technique commonly used