Research Of JPEG2000 Image Standard And ROI Coding

With the increasing use of multimedia technologies, image compression requires higher performance as well as new features. To address this need in the specific area of still image encoding, a new standard is currently being developed, the JPEG2000.JPEG2000 is the latest image compression standard developed by ths ISO/ITU-T. JPEG2000 Part I ,the core-coding algorithm, became an international standard in December 2000. JPEG2000 provides, in a single bit-stream, a broad set of functionalities. Region-Of-Interest (ROI) image coding is a new feature in the JPEG2000 , which allows ROIs to be coded with better quality than the rest of an image, i.e., background.Firstly the general information of the JPEG2000 still image compression standard is outlined, and each part of the JPEG2000 coder is discussed in detail according to the JPEG2000 encoding order, especially about the EBCOT codec. The three methods by which ROI coding can be achieved in JPEG2000 (tiling; code-block selection; and coefficient scaling) are then discussed, especially ths Maxshift method is analysed. Then the relative performances of Maxshift method and code-block selection are experimentally investigated. Finally we realized modified ROI coding method. The experimental results show that the modified ROI coding method combines the advantages of the two standard ROI coding methods defined in JPEG2000.