Fast Fractal Encoding in Frequency Domain

Fractal image compression applies the self-similarity property of image. Many researches have been done to study the properties of fractal coding in image domain. In this paper, however, we try to explore the features of fractal coding in frequency domain. We rstly overview the properties of fractal coding in image domain, then we derive the corresponding formula of scaling factor and o set of a ne transform in DCT domain. Applying the energy compaction property of DCT, we propose a fast fractal encoding algorithm by using only a small number of low frequency DCT coe cients in measuring the similarity between range block and domain block. We further propose a possible fast hybrid fractal encoding algorithm which combines existing fast search methods, statistical normalization and frequency domain comparison.