Adaptive successive approximation quantization of image waveforms with efficient codebook updates

A design method for adaptive successive approximation residual vector quantizers with suboptimal but computationally efficient sequential search encoders is given. Image-specific codebook adaptation and the sequential search encoder structural constraint are shown to be more easily accommodated with the use of separate, and in general, different encoder and decoder code books. The design method generates encoder codebooks that provide computationally efficient successive approximation tree structures, and generates decoder codebooks that satisfy conditions necessary for joint optimality. Design monotonicity is maintained even with the use of small training sets sizes, as required by image-specific codebook adaptation. The memory advantage of the direct sum structure permits image adapted codebooks to be efficiently stored or transmitted as overhead information