基于小波零树的医学图像压缩研究

【作者】 李振伟；

【导师】 何继善；

【作者基本信息】 中南大学 ， 生物医学工程， 2004， 硕士

【摘要】 数字影像技术在医学中的广泛应用，产生了大量的数据，给图像的存储和传输技术提出了严峻的挑战，解决它的关键技术之一就是医学图像压缩技术。 医学图像压缩的目的是在保证图像使用质量的前提下将图像的信息转换成另外一种能使数据量缩减的表达形式。医学图像压缩方法很多，其中小波图像编码发展最快，主要是因为它具有多分辨率分析特性，即可以和子带编码有机统一，又能和人眼的视觉特性相结合，因此成为医学图像压缩编码领域的一只主力军。 基于小波分析的医学图像压缩方法很多，最经典的是Shapiro于1993年提出了嵌入零树小波(Embedded Zerotree Wavelet，EZW)算法。但由于它存在着诸如效率较低、没有充分利用小波的多分辨率分析特性等缺点和不足之处，所以这种算法并不完美。针对这种方法的缺陷，在实现EZW算法并分析其现有改进算法的基础上，本文作者将行程编码方案引入嵌入零树小波医学图像压缩算法，提出了自己的改进意见：首先对医学图像进行嵌入零树编码，然后对编码后的符号串进行行程编码，最后再对行程编码后的码流进行自适应二进制算术编码。实验结果表明，这种零树与行程相结合的医学图像编码方案可以提高压缩比，改善压缩性能。 研究开发出有效的医学图像压缩算法对医学图像的存储和传输都有着重要的意义，它可以节约存储空间和传输时间，方便医学图像的管理和运用，更好地服务于临床诊治。更多还原

【Abstract】 The wide use of digital image technologies produced a great deal medical data, which challenged the image Archiving and Communication technologies. Medical image compressing is one way to solving it.The aim of medical image compression is transforming its information from one form to another, which can reduce its data stream. There are many medical image compression methods, in which wavelet image coding is one important aspect because its ability of multi-resolution, meanwhile, it can combine itself with sub-band coding and HVS(Human Vision System).There are many image compression methods based on wavelet analysis. The most typical of them is EZW(Embedded Zerotree Wavelet) algorithm, which was put forward by Shapiro in 1993 .But it has shortcomings, such as low efficiency, having not used the multi-resolution property of wavelet, and so forth. Therefore, this algorithm is not ideal. According to this, the author brought RLC(Run Length Coding) to EZW and improved the algorithm based on the analysis of EZW algorithm and its improved algorithms in existence. The author firstly code the image with EZW, then code the output of EZW using RLC, and finally code the stream of RLC with adaptive binary arithmetic method. The result showed that the combination of EZW and RLC is better than EZW in Compression Ration.The study of effective medical image compression algorithm is very important to PACS(Pictures Archiving and Communication System). It can save storage space and communication time, improve the efficiency of medical images management and using. Accordingly, serving the clinic diagnosis and treatment.更多还原