基于对象的三维医学图像形状自适应编码算法  

Object-Based Shape-Adaptive Coding Method for Three-Dimensional Medical Images

作　　者：吴家骥[1] 焦李成[1] 石光明[1] 王磊[1] 

机构地区：[1]西安电子科技大学智能信息处理研究所

出　　处：《软件学报》2008年第7期1635-1643,共9页Journal of Software

基　　金：the National Natural Science Foundation of China under Grant Nos.60607010,60672125,60672126,60736043,60776795(国家自然科学基金);the Program for Cheung Kong Scholars and Innovative Research Team in University of China under Grant No.IRT0645(教育部长江学者和创新团队支持计划);the Natural Science Foundation of Hu'nan Province of China under Grant No.08JJ3123(湖南省自然科学基金)

摘　　要：提出了一种针对三维医学图像已知诊断对象区域的形状自适应小波编码方法.该算法仅对对象区域内的像素应用形状自适应小波变换去相关,变换后,对象在变换域中的系数个数与图像域的像素保持相同.为了实现快速无损变换,提出一种基于提升的形状自适应小波变换方法.通过分析形状自适应变换后无效系数的位置,又提出一种改进的OB-3DSPECK(object-based set partitioned embedded block coder)算法,取消了对象区域外无效块或系数的符号输出,即只输出两种符号码流到自适应算术编码器.对于三维医学图像的对象区域,该算法能够提供有损到无损的渐进编解码.实验结果表明,该算法平均SNR比OB-3DSPECK提高0.5dB.此外,由于减少了一种符号输出,使得算术编码过程可选.The paper proposes a shape-adaptive wavelet coding algorithm for known object of diagnostic region of three-dimensional medical images. The new algorithm only applies to the shape-adaptive transformation of the pixels inside the object for decorrelation. After transformation, the number of coefficients of the object is as many as that of the pixels inside the image area. To achieve a quick and lossless transformation, a novel shape-adaptive wavelet transform based on lifting scheme for arbitrarily shaped object is proposed. By analyzing the location of invalid coefficients transformed, the paper also proposes a modified OB-3DSPECK （object-based set partitioned embedded block coder） method that cancels symbol outputs of invalid block or coefficients outside the object, specifically, only two types of symbols are output to arithmetic coding coder. For object region of three-dimensional medical images, the proposed algorithm supports the lossy-to-lossless embedded en/decoding. Experimental results show that the proposed algorithm outperforms OB-3DSPECK by 0.5dB on the average SNR. Furthermore, because of the reduction of the output of one type symbol, the arithmetic coding becomes optional.

关 键 词：形状自适应变换 嵌入编码 基于对象编码 小波变换 SPECK(set partitioning EMBEDDED block) 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]