The Study, Based On Jpeg2000 Region Of Interest Algorithm

JPEG2000, the new ISO/ITU-T Standard for still image encoding, had been finished at the end of 2000. Compared with the JPEG standard, JPEG2000 standard adopts some different compress technique, such as the Discrete Wavelet Transform, Embedded Coding and so on. So it has better compress performances, including Progressive Display, Region of Interest (ROl) encoding.Firstly, JPEG2000 standard is introduced, including the basic theory and every module in its encoding/decoding system. The programming results are analyzed and compared with those of the JPEG standard. Then, the research of ROI is mainly involved, which allows the ROI to be coded with better quality than the background of an image. The MaxShift method is adopted in JPEG2000 Part Ⅰ. For the MaxShift method does not have the flexibility to select a scaling value to define the relative importance of the ROI and the background wavelet coefficients, two new methods are realized: Most Significant Bitplane Shift (MSBShift) method and Bitplane-by-Bitplane Shift (BbBShift) method. The programming results prove that the two improved methods support both arbitrary ROI shape and arbitrary scaling without shape encoding.