A hybrid image compression scheme combining block-based fractal coding and DCT

Abstract A novel hybrid image compression scheme based on block-based fractal coding and discrete cosine transform (DCT) is proposed in this paper. An original image is first compressed by DCT domain fractal transform instead of spatial domain fractal transform, then the difference image between the original image and its fractal approximation is quantized and encoded by a Huffman code. The detailed steps to implement the scheme and some experimental results are presented. A comparison with other fractal-based image coding methods is also made in the paper. Experimental results show that when compressing the standard image ‘Lena’ with this technique, for a compression ratio of 12.4, its PSNR can reach 31.7 dB.