ABSTRACT
In this chapter, the authors describe the differential technique in general. They discuss two components of differential coding: prediction and quantization. The authors also discuss the idea of differential coding involving image sequences. They emphasize prediction, outline the optimum linear prediction problem and present a theoretical solution to the problem. Instead of encoding a signal directly, the differential coding technique codes the difference between the signal itself and its prediction. The differential coding technique has played an important role in image and video coding. In a general differential pulse code modulation (DPCM) system, a pixel’s gray-level value is first predicted from the preceding reconstructed pixels’ gray-level values. Since DPCM consists mainly of two parts, prediction and quantization, its optimization should not be carried out separately. The interaction between the two parts is quite complicated, however, and thus combined optimization of the whole DPCM system is difficult.
