Image Coding: Variable Rate Differential Pulse Code Modulation Through Fixed Rate Channel
Andrew G. Tescher, Richard V. Coxt · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1977
A previously-developed block adaptive Differential Pulse Code Modulation (DPCM) procedure has been combined with a buffer feedback technique. The result is an efficient variable rate DPCM algorithm. The new technique is fully adaptive, yet it retains the basic simplicity of DPCM. It utilizes the appropriate quantizer parameters and also assigns the available channel bandwidth according to need as determined by the local image structure. A buffer feedback procedure, previously reported by the authors, has been generalized and was implemented to control the bit rate selection. Examples demonstrate that the algorithm is successful in achieving adaptivity objectives. Although buffer control requires additional hardware, because of its relatively low speed, the impact on overall hardware complexity is negligible.