Intraframe coding for picture transmission

A great variety of intraframe coding techniques have been proposed and demonstrated in recent years. Most of them exploit the properties of both the image and the human viewer. These properties are discussed briefly so as to provide a framework for describing the various coding techniques. The development of intraframe coders has been an evolutionary process. Techniques such as delta modulation (DM) and differential pulse code modulation (DPCM) which were proposed in the early 1950's are still being actively studied and improved today. A survey of this early work is given as a preliminary to more detailed discussion of the work from 1967 to the present. Three main approaches are evident in these studies. First, by making linearizing assumptions, frequency domain analysis can be applied to the problem of minimizing the visibility of granular coding noise. Second, in order to exploit the nonlinear properties of the human visual system, a time domain approach to the development of coding algorithms is found most useful. Third, by exploiting only the statistics of the source, efficient reversible encoding operations can be developed. These three approaches are dealt with in some detail. Possible avenues for further research are pointed out.