A new hybrid wavelet-fractal coder (WFC) for image compression is proposed in this research. We show that the application of contractive mapping for interscale wavelet prediction in the wavelet domain offers bit rate savings in some regions. The prediction residue is then quantized and encoded by traditional wavelet coders. WFC allows the flexibility to choose either direct coding of wavelet coefficients or fractal prediction followed by residual coding to achieve a better rate-distortion (R-D) performance. A criterion of low complexity is derived to evaluate the R-D efficiency of fractal prediction. The superior performance of WFC is demonstrated with extensive experimental results.
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