Research And Implementation On Static Image Coding

With the continuous development of multimedia technology and network, static images are becoming increasingly widely used. In specific applications, the static images take up a great many resources in the storage and transmission, and cause much inconvenience. In this case, static image compression has become a research hotspot. People want to use the limited storage capacity and transmission bandwidth to transmit bigger size images, and hope that the compressed image has better image quality. In this background, the ISO issued a series of static image compression standards, and the most famous are the standards—JPEG and JPEG2000.JPEG is short for "digital compression and coding of continuous-tone still images", and the N.O. of this international standard is ISO/IEC 10918, which is currently the most widely used image compression standard. JPEG2000 is the next generation static image compression coding standard, and the N.O. of this international standard is ISO/IEC 15444, which is an upgraded version of JPEG, with superior compression performance. This paper described the research and implementation based on these two standards. This paper completed the following major tasks:1) Performed a systematically theoretical study of the coding and decoding of the JPEG standard, introduced the major modules in detail , and programmed to convert a BMP format image to a JPEG format image and vice verse with Visual C + +, Finally,the paper introduced the look-up table DCT and using the adaptive quantitative method instead of the standard quantitative method to achieve the purpose of improving the quantity of compression.2) Performed the theoretical research on the coding and decoding of basic system of JPEG2000 standard, presented detailed description about the main modules including wavelet transform and entropy coding, and realized the mutual conversion between a BMP format image and JP2 format image with the reference code of kakadu_V2.2.3 edition.3) Compared the main characteristics and image compression performance between JPEG and JPEG2000 and concluded: in some low compression ratio cases, JPEG2000 cannot replace JPEG because of the complexity of its algorithm. However, in some high compression ratio circumstances, or in some special requirements cases (such as: ROI (Region of Interest) coding), JPEG2000 will be the best choice.Finally, this dissertation summarized the work that has been done, pointed out the deficiency of this research and determined direction of the future study.