| Image is one of the most important data in multimedia technology. The image processing and analysis have developed to be the specialized branch of the modem signal processing technology with its rapid development. So it is necessary to research the specialized technology. In recent years, with the development of wavelet theory and application, the wavelet image processing has made great progress in comparing with the former image processing methods. Therefore, people have always been very interested in the issue that wavelet transform is used in image processing, particularly in image compression. This is also the reason why the paper is going to research and discuss this.In this thesis, image compression algorithm is the main research object. The basic wavelet transform theory has been analyzed. Then EZW image compression algorithm based on wavelet transform is researched and discussed.The main results are as follows:1. Present and discuss the digital image compression method, the research background and the international standards of some classic coding methods.2. Discuss the wavelet transform coding based on wavelet transform theory and the EZW algorithm is the highlight. Regarding to its shortcomings and deficiencies, two improved algorithms based on EZW algorithm is presented. The new two algorithms improve the coding and decoding time and the experiment has verified it.3. An improved wavelet transform coding based on EZW algorithm is presented after the human visual system (HVS) is introduced. The experiment result has verified the effectiveness of the new improved algorithm. The improved algorithm not only bears the effective compression performance of the original EZW algorithm, but also improves the visual quality of image very well. |
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