The Study Of Still Image Compression Methods Based On DCT & WT

Discrete Cosine Transform (DCT) and Wavelet Transform (WT) are adopted by international still image compression standards. It is important and evaluable to study image compression algorithms with both of the transforms and to realize the functions defined in standards.In this thesis, the main idea and basic methods of image compression encoding are investigated based on the standards of JPEG and JPEG2000. The still image compression by using DCT & WT is focused. Dealing with the JPEG Baseline compression, optimal RLC and Huffman coding methods are presented. The PTC Progressive Transmission) and ROI C Region-of-Interest) are implemented and the related problems including embeded zerotrees encoding, net realization and compression rate are also discussed.The gray image "lena.bmp"(512 X 512 X 8bit/pels, 257000bytes) is used to be the test example and the results show that the method and algorimths proposed here are effective and feasible.The related software is developed on Matlab and Visual C++ for Windows.