The Research On Application Of Wavelet Based Digital Image Technology

The Wavelet Transform used in digital image compression is an important part of its application. The Wavelet Transforms is good at high compression ratio and speed; it can keep the feature unchanged after the compression and Anti-jamming during the transfer.JPEG 2000 standard which is created by the Joint Photographic Experts Group committee in the year 2000 used Discrete Wavelet Transform (DWT) instead of Discrete Cosine Transform (DCT) which is used in JPEG The JPEG 2000 standard has improved the image quality and could do both Lossy Compression and Lossless Compression; it also has the function of the error correction.This paper is aiming at 5/3 DWT and 9/7 DWT which are used in JPEG 2000 standard. It introduced the base theory of the Wavelet Transform at first and showed the deducting procedure of DWT, 2-D Wavelet Transform. Then it illustrated the structures of 5/3 DWT and 9/7 DWT.The Wavelet Transform as an important part of JPEG 2000 standard, its parameter would impact the image quality directly. This paper did some research works on it and analyzed the impact of the number of Wavelet Transform level and the choice of Wavelet according the experiments' result.The implementation of 5/3 DWT and 9/7 have been researched in this paper, and the issue of the expansion of cyclical signal is also has been discussed. The application architecture and pseudo code of the lifting scheme of 5/3 DWT and 9/7 DWT were showed in this paper. The issue of the max value of intermediate results during the DWT which was faced in the project has been also proved.The decimal precision is another important part which will impact the image quality. This paper implemented it by converting the float decimal to the fix decimal, which has the guiding significance with the actual project.