Image coding using successive approximation wavelet vector quantization

A novel coding method of wavelet coefficients of images using vector quantization, referred to as successive approximation wavelet vector quantization (SA-W-VQ) is proposed. In this method, each vector is coded by a series of vectors of decreasing magnitudes until a certain distortion level is reached. Analysis of the successive approximation using vectors is given, and conditions for convergence are derived. It is shown that lattice codebooks offer an efficient tool to meet these conditions, with the extra advantage of fast encoding algorithms. In SA-W-VQ, distortion equalization of the wavelet coefficients can be achieved together with high compression ratio and precise bit rate control. Simulation results for still image coding show that SA-W-VQ outperforms both the EZW coder and the standard JPEG