Low bit rate color image coding with adaptive encoding of wavelet co-efficients

This paper reports the performance of the embedded zerotree wavelet (EZW) using successive-approximation quantization and an adaptive arithmetic coding for effective reduction in bit rates while maintaining high visual quality of reconstructed color images. For 24 bit color images, excellent visual quality is maintained up to a bit rate reduction to approximately 0.48 bpp by EZW yielding a compression ratio (CR) of 50:1. Further bit rate reduction to 0.375 bpp results in visible degradation by EZW as well as by a recently developed adaptive vector quantizer, namely, AFLC-VQ.