Data Compression Dictionary and a Quick Image Compression Algorithm Based on Fractal Mapping

The compression time of fractal coding algorithm is so long that the algorithm is hardly useful in reality. The idea to preprocess the image by means of many grey levels was presented. It constructs a data compression dictionary based on compressed image, so that the compression block matched in the image is only searched in the data compression dictionary. As a result, this algorithm greatly shortens the compression time and the searching scope in the compression procedure,compared with other algorithms of the fractal block coding. In addition, the theoretical basis of constructing the data compression dictionary was obtained. Based on the new compression idea, a concrete algorithm of realizing fractal image coding was designed. The new algorithm can improve compression ratio while reducing encoding time.