The essay , first of all , researchs jpeg2000 and implements the kernel code of compressing dicom with jpeg2000 . on the basis of it , gives an improvement , and then combines image denoising and image compression to get better lossy compression effect ; discusses several lossless compression ways of medical image sequence ; in the end , discusses or analyses many problems of compressing with jpeg2000 , and tests all the methods said in the paper 并在此基础上给出了一种对jpeg2000的改进算法;接着将图像的小波降噪方法与jpeg2000相结合,以得到更好的有损压缩效果,同时给出了一种提高压缩比的方法;再接着讨论了几种提高医学序列图像无损压缩的方法;最后讨论和分析了jpeg2000在压缩dicom时所涉及的问题;并对所提出和讨论的方法进行了相关的试验。
Experimental results show that the watermarking algorithm presented in this thesis can survive general lossy compression , such as jpeg , noise and lowpass filter manipulation . the robustness of watermarking is related with the length of spread spectrum sequences . the longer the spread spectrum sequences are , the more robust the watermarking is 实验结果表明，本文提出的算法能抵抗一般的有损压缩( jpeg ) ，加噪和滤波处理，而且水印的鲁棒性与扩频序列的长度有关系，扩频序列长度越长，水印的鲁棒性越强。
The data compession technology is researched , and the problem is solved which quanties of fault recording data are huge and the sending time is long . the transmission success ratio is boroved greatly . the electrical relation of single phase - earth fault of generator stator windings is ndied in detail , and the process of generator losing magnetism faul is also discussed 利用该标准记录数据中的冗余量，进行压缩是一新思路，对无损压缩和有损压缩进行了大量仿真，采用信号源符号1byte的自适应二阶算术编码无损压缩法，使远传数据压缩率可达72 ，解决了录波数据远传中数据量大、传送时间长、成功率低的难题。
Presently , most of the researchers focused their attention on the lossy compression of bionedical signals , but lossless and near - lossless compression is practically expected because the general lossy compression techniques can not serve the high fidelity requirement of signals in this field 鉴于当前生物医学信号压缩技术主要偏重于有损压缩技术的研究，而较少研究无损近无损压缩技术，然而在临床和科研应用中，首先要求的是生物医学信号必须具有高可信度，所以更期望使用无损或近似无损的压缩技术。
We study the code model characteristic of videos , analyse the characteristic of mpeg data structure and similarities and differences of forms of avi video . the method which compresses the information of an image and the differences of images is adopted to reach the high compression ratio . mpeg compresses algorithms as the international standard , is supported together by many computer platforms now , have better compatibility than avi video 论文首先简要地介绍了课题背景和当前的研究状况，研究了视频编码模型特点，分析了mpeg - 2数据结构特点和avi视频格式的异同，在同等的视觉质量范围下mpeg - 2采用有损压缩方法减少运动图像中的冗余信息从而达到高压缩比，因此mpeg - 2压缩算法作为国际标准，被许多的计算机平台共同支持，较avi视频具有更好的兼容性。
To solve the problem of watermark encryption , a novel permutation operator is proposed , based on which the permutation scheme and the substitution scheme for watermark encryption are designed ; encryption algorithms in spatial domain and transform domain are proposed . the ciphered image can be jpeg compressed before it is transmitted , and low - distortion plain image can be obtained after decrypting the compressed encryption image 为解决水印信息加密问题,我们在第三章提出混沌有序化算子方法,设计了水印信息加密的置乱模块和替代模块;还给出了空间域和变换域数字图像加密算法,密文图像可以经过有损压缩再传输,经过解密得到低失真的明文图像。
The image compression technology based on region of interest utilizes different compression to different area in an image , it can solve the contradiction between the image quality and the compression rate . in the paper , first , the research background and development of image processing are introduced ; then an algorithm utilizes integer - to - integer wavelet transform , maxshift and spiht is brought forward 图像的感兴趣区域压缩编码技术，即在图像中的感兴趣区域( roi )进行无损或近无损压缩，而在其它区域采用有损压缩，从而既可以获得所期望的高质量的图像信息，又保持了较高的压缩比，很好地解决了压缩比和图像质量之间的矛盾。
This paper introduces the principle of wavelet transform and the foreground of which in the image compression fields and realizes to compress the medical image with matlab which is a very popular software . we adopt the lossless compression for region - of - interested and for the region - of - uninterested where the significance is very small and we reference it only we adopt the wavelet compression of high compressibility . thus high compression ratio is gained and it is favorable to the storage and transmission of medical image 本文着重介绍了小波变换的原理和在压缩领域中的广泛前景，并运用目前非常流行的软件matlab实现了对医学图像的压缩，对感兴趣区域( region - of - interested ， roi ) ，在压缩编码时采用无损压缩，而对实用意义小，只有参考价值的图像区域( region - of - uninterested ， uroi ) ，可以采用高压缩比的小波有损压缩，从而实现较高的压缩比，利于医学图像的存储与传输。
On the basis of these , we further bring forward a method to decrease the computational complexity of lifting scheme , which is used in jpeg2000 and shows high performance . this dissertation first retrospects the basic principles of jpeg compression standard , and then points out the deficiency of jpeg : square effect when the cr is very high , and only if dct is taken the place of by dwt , this shortcoming can be overcome and some new features can be realized : such as progressive coding , from lossy coding to loseless coding and roi coding 本文首先回顾了jpeg压缩标准的基本原理，随后了阐明了该压缩标准的局限性-高压缩比时重建图像的方块效应，而惟有把离散余弦变换( discretecosinetransform )改为小波变换( wavelettransform )才可能克服现有的局限性并且还可以实现许多新的功能，如渐进编解码、从有损压缩到无损压缩和感兴趣区域编码等。
3 . lossy and lossless image compression is realized by means of integer wavelet transform , and the shortcoming of pure lossy compression with non integer ones is overcame . here the influence of different wavelet base to the effect of compression is discussed , and conclusions are obtained as follows : to the choice of wavelet base in spiht image codec , in lossless codec , integer lg5 / 3 and in lossy codec , non integer db9 / 7 wavelet base is recommended 3 、将整数小波变换应用于图像编码之中，克服了非整数小波变换只能有损压缩的缺点，实现了图像从有损到无损的压缩，并分析了不同小波基对压缩性能的影响，最后得到如下结论：在spiht压缩编码中，有损压缩推荐使用非整数db9 7小波变换，无损压缩推荐使用整数lg5 3小波。
