Quadtree-Guided Wavelet Image Coding

A hybrid of wavelet and quadtree image coding is introduced. It uses a recently developed quadtree predictive coding technique, having good rate/fidelity performance and very low complexity, to encode the baseband wavelet coefficients. The resulting quadtree decomposition of the baseband is then used to guide the encoding of higher frequency subbands, by indicating which of their coefficients require encoding and which do not. The result is a coding method with performance comparable to those of the best known wavelet coders, but with less complexity. I. Introduction Subband image coders based on discrete wavelet transforms have produced some of the best, if not the best, image coding results (c.f. [1-7]) in the sense of good rate vs. fidelity characteristics (both PSNR and perceptual) with reasonable complexity. Aside from producing good subband decompositions, recent wavelet coders have also benefited substantially from clever ways of exploiting the similarity of subband images at o..