Efficient Quadtree-based Fractal Image Coding Scheme in Wavelet Transform Domain

摘要

This paper presents an efficient quadtree-based fractal image coding scheme in wavelet transform domain based on the wavelet-based theory of fractal image compression introduced by Davis. In the scheme, zerotrees of wavelet coefficients are used to reduce the number of domain blocks, which leads to lower bit cost required to represent the location information of fractal coding, and overall entropy-constrained optimization is performed for the decision trees as well as for the sets of scalar quantizers and self-quantizers of wavelet subtrees. Experiment results show that at the low bit rates, the proposed scheme gives about 1 dB improvement in PSNR over the reported results.