Medical Image Data Compression Research In PACS System

In recent years,as the multimedia techology,computer network and communica-tion technology development, PACS has a great achievement, and digital medical image in medicine clinical diagnosis and the teaching research play an important roles and has a wide range of applications. Because of medical image with a large amount of data,large storage space wide transmission frequency band, etc,it seriously influenced the development of the PACS. In addition, high-fidelity of the medical image influences the doctor diagnosed the illness. So, With DCT, wavelet transform technology, the major objective of this article should improve Compression ratio and the high fidelity degrees for the medical images that are kind of special images. And the existing algorithm was improved for improvement of the image reconstruction.Based on the algorithm of DCT, since the image segmentation before transforming, in quantitative coding, no full consideration of difference of the adjacent piece of quantitative step length result in blocking artifacts in the block boundary. For this reason, this paper proposed a based-the post-processing technology to reduce block effect.First to test, The corresponding set four models, and according to the different mode choice different filter to filter block edge, removing blocking artifacts. Based on the wavelet transformation of the image compression method, with the traditional SPIHT in code,the subbands originally neglected by the SPIHT algorithm neglected exhibits quite a large correlation among the same level subbands. This article uses an8×8Discrete Cosine Transform approach to perform subband and modified set partitionning in hierarchical trees(SPIHT) employed to organize data and entyopy coding.The translation function can store the detailed characteristics of an image.A transformation to deserve DCT spectrum data in a frequency decomposes the original signal into various frequency that further compressed by wavelet-based algorithm.Cmpared the post-processing technology to block the effects with The traditional JPEG image compression method, the image visual quality and compression ratio of the reconstruction have been significantly improved. Improved SPIHT algorithm reduces correlation among the same level subbands and raises image compression ratio.