| With the computer technology and multimedia technology development, more and more digital information needs for storage and transmission. In order to store and transfer of these information efficiently, data compression becomes more and more important. In this paper, we studied of Fractal Image Compression Coding, the branch of image compression in Digital Compression. Fractal Image Compression Coding with the advantage of high compression ratio, resolution independence and fast decoding attract many scholars, but the shortcoming which coding time is too long limits its wide application and further development.In this paper, we introduced the background and the research status of image compression firstly. And then, discussed the basic principles of fractal coding and algorithms in detail and carried out related studies on Basic Fractal Image Coding of improved algorithm. Briefly described the main directions to the current of improved algorithms and their respective advantages and disadvantages. On this basis, two kinds of improved algorithm were proposed in this paper:1. Used the classifiable of the domain block, we proposed Fractal Image Coding Algorithm Based on Classification of Sub-Block Feature. It used the similar characteristics of sub-block, converted the basic fractal image coding's entire search into nearest neighbor search of a relative difference, and only searched the domain blocks which have the same difference.This method can reduce the search space and find out the best matched block in a small amount of domain blocks, achieve the speedup of image coding.2. Combined the fractal image coding with genetic algorithm, we proposed Based on Improved Genetic Algorithm's Fractal Image Coding. We used the improved algorithm's optimal solution search capabilities to replace the complex process of block matching in fractal image coding, and combined with the contrast of contract scaling factor.This method can limit the search space and speed up the encoding process. |
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