| With the development of multimedia technology, more high-performance image compression is expected to advent. As a new and excellent method used for signal analysis and processing,wavelet analysis is becoming one of the most important methods because of its perfect performance on both time and frequency domain in recent years. Firstly, on the basis of the principle of the image compression, we study the theory and basic algorithm of image compression detailedly. By experiment we compare the basic principle of JPEG compression standard with that of JPEG2000 still image international compression standard. The result shows the deficiency of JPEG: square effect when the CR is very high. But if DCT (Discrete Cosine Transform) is taken the place of WT (Wavelet Transform), the shortcoming of JPEG can be overcome and some new fuctions can be fulfilled, for example progressive coding, lossy-to-loseless coding and ROI (Region Of Interests) coding. And some core techniques of the JPEG2000 standard are elaborated detailedly such as EBCOT algorithm and ROI coding. Finally just as for ROI coding technique we further give out a novel algorithm of the still image classification compression. The algorithm bases on wavelet and, under the limited storage space condition, encodes the image in a better quality way inside the region of interests, and automaticly sets the edcoding grades according to the available storage space condition. The simulation experiment results of the algorithm on a photo show that it can rebuild a better quality inside the region of interests when meeting the command of the compression ratio. A deep researeh on still image compression is presented in this dissertation. The algorithm of still image classification compression can be applied for the Digital Personal Identification System, Discernment of the Number Plate System and Tele-medicine Operation System, etc. The algorithm has extensive application expections and brilliant development prospect.
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