关键词: 图像压缩, 分形, 迭代函数系统, 分辨率

Abstract: Fractal image compression is an efficient technique for encoding images. It can lead to a high compress ratio and decoding quality in theory. But, the speed of basic automatic fractal encoding is slow and the decoding quality is also unsatisfactory when the compress ratio is higher.This paper gives a way to get a fast speed of encoding. We reduce the original image to the 1／4 resolution, encode the 1／4 resolution image by the basic fractal algorithm, get the fractal code of the 1／4 resolution image, and decode the code to the original resolution. Then we calculate the difference between the decode image and the original image, and encode the difference image in a simple way. The code of the 1／4 resolution and the code of the difference image constitute the code of the original image.This method can speed up about 3-4 times with the same PSNR as for the basic automatic fractal algorithm.

Key words: image compression, fractals, iterated function system, resolution