Embedded wavelet zerotree coding with direct sum quantization structures

One of the more effective data compression systems that has been recently proposed is the relatively simple embedded wavelet image coder developed by J.M. Shapiro (1994). Two key components of Shapiro's system are the use of zerotrees to keep track of insignificant subband coefficients and progressive transmission of successive bit planes of significant coefficients. Shapiro's quantization mechanism is the use of scaled successive approximation uniform scalar quantizers. This paper investigates ways of improving the performance of embedded wavelet coders with the use of optimized successive approximation direct sum quantization structures.