We propose a time improved fractal image coder with a reduceddomain pool and optimal luminance transform parameters calculation. Thisscheme is applicable to the Fischer's (1994) classification method. Weaccelerate the encoding process by reducing the domain pool and then byminimizing the number of operations for the similarity search; thisreduction is based on discarding the domains with nearly the samevariance from each class of the domain pool. This approach provides agreater speed loss with a slight loss in the compression ratio and aslight improvement in the image quality. In our experiments anacceleration of 6.7 for the image “Lena” is reached with agood decoded image quality. For a speed up factor of 2 the compressionratio is about 0.8% reduced and the image quality is about 0.23%improved. In order to increase the compression ratio again we useJaquin's (1992) method and we remove some of the range blocks with shadeproperty from the search
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