随机中点位移算法的改进

Upper Bound on Redundancy Reduction in Predictive Entropy Subband Image Coding

在研究用于分形图象生成的随机中点位移算法原理和实验结果的基础上，提出了改进的随机中点位移算法，以便生成具有预定基本形状和轮廓的分形图象，并通过编程实验验证了改进算法的有效性。

This paper deals with the estimation of the theoretical and practical performance efficiency of a subband coding system for still images using memoryless quantizers optimized to entropy and mean square error constraints. An approach with the concept of rate distortion theory has allowed to derive a function in special form, which gives the performance gain in terms of signal to noise ratio and redundancy reduction. The theoretical upper bounds on entropy coded bit rate reduction were found to be 1.10; 1.51 and 2.10 bits per pixel for M = 4, 7 and 16 subbands, respectively. Some simulation results concerning practical performance are presented and interpreted on test images.