Joint optimization of lattice vector quantizer and entropy coder in subband coding
Wonha Kim, Yu Hen Hu, Truong Q. Nguyen · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1997
This paper presents an algorithm that jointly optimizes a lattice vector quantizer (LVQ) and an entropy coder in a subband coding at all ranges of bit rate. Estimation formulas for both entropy and distortion of lattice quantized subband images are derived. From these estimates, we then develop dynamic algorithm optimizing the LVQ and entropy coder together for a given entropy rate. Compared to previously reported min-max approaches, or approaches using asymptotic distortion bounds, the approach reported in this paper quickly designs a highly accurate optimal entropy- constrained LVQ at all range of bit rates. The corresponding wavelet-based image coder has better coding performance comparing with other subband coders that use entropy- constrained LVQ, especially at low bit rates.