A fast fractal encoding algorithm based on sub-block subtraction

To overcome the long encoding time of fractal image coding, many methods have been proposed and most of these are based on image blocks classification or feather matching. It is really a good choice to convert the entire search into the nearest neighbor search defined under some situation. This paper proposes a fractal image encoding method based on sub-block subtraction, which converts the entire search into the nearest neighbor search and saves plenty of time. We also present the feasibility analysis. By comparing with the basic fractal algorithm, the simulation result shows that the proposed algorithm not only can guarantee the same image quality but also can improve the encoding speed.