空间太阳望远镜中图像的小波压缩算法及软件设计

【作者】 田丽霞；

【导师】 周晓军； 金声震；

【作者基本信息】 电子科技大学 ， 光学工程， 2002， 硕士

【摘要】 本文主要介绍了空间太阳望远镜中图像的小波压缩算法及软件设计。具体如下： 从工程的角度简要介绍了小波变换的基本理论，然后在此基础上提出二维小波变换程序设计过程中遇到的几个问题及其解决办法。 由嵌入式小波零树编码(EZW)引入，详细阐述了其变体——“基于集合划分的等级树编码(SPIHT)”的算法思想，以及SPIHT编码程序设计过程中遇到的一些问题。实验结果表明，小波SPIHT编码已足敷SST应用。 为了进一步提高图像压缩质量，在SPIHT编码的基础上引入了算术编码。本文简单介绍了算术编码的基本思想，实验结果表明，在小波SPIHT编码的基础上加入算术编码，图像压缩效果有所改善。 小波包图像压缩是当前小波图像压缩领域的一个新热点，前人已经在这方面做了很多工作。本文介绍了小波包的基本概念，并着重介绍R-D小波包优选算法；阐述了零树编码应用于小波包图像压缩时出现的不规则父子关系及其解决办法；针对R-D小波包优选算法与零树编码相结合时量化精度不相“匹配”的问题，创造性地提出修正R-D优选算法的思路；实验结果表明，在较大的压缩比(较大比特率)下，采用修正R-D优选小波包零树编码方案可以得到比前人的最大熵优选小波包零树编码方案更优越的图像压缩效果。更多还原

【Abstract】 The main idea of this paper is to introduce the process of algorithm devising and software developing of wavelet image compression in Space Solar Telescope.Theories about wavelet transform are introduced briefly from the perspective of engineer, then based on these theories, the disposal of some problems that arises during the programming process of two dimensional wavelet transform.After introducing the main idea of EZW(the Embedded Zerotree Wavelet algorithm), the author described "wavelet image compression based on SPIHT (Set Partition InHierarchical Trees)" ---- another "perspective" of EZWexplicitly, some problems that arises during the programming process are also provided here. Experiment results show that pleasurable reconstructed images can be obtained by applying this scheme.In order to get better reconstructed images, arithmetic coding is added to SPIHT scheme. The main idea of arithmetic coding is introduced briefly in this paper, experiment results show that better reconstructed images can be obtained after adding in arithmetic coding.Wavelet packet image compression is one of the focuses in the domain of wavelet image compression, much work has been done by others. In this paper, some main ideas about wavelet packet are introduced, in which the rule named R-D rule which was developed to select the best wavelet packet bases is introduced at length; While applying SPIHT scheme to wavelet packet image compression, the multi-father problem arises, the-n-problem and the disposal of it are then explained; Noticing the difference of the precision that are used to describe the datum in R-D rule and SPIHT scheme, creatively, the author advanced a new method to rectified the R-D rule , the new rule and the programming of it are then provided; Comparing the results with those of past, the method can get even better reconstructed images at high compression ratio, this proves that the rectified R-D rule is reasonable.更多还原