基于游程和扩展指数哥伦布编码的任意形状感兴趣区域图像编码  

Arbitrary shaped ROI image coding using Run-length coding and generalized Exp-Golomb coding

作　　者：徐勇[1,2] 徐智勇[1] 张启衡[1] 

机构地区：[1]中国科学院光电技术研究所,四川成都610209 [2]中国科学院研究生院,北京100039

出　　处：《光学精密工程》2011年第1期175-182,共8页Optics and Precision Engineering

基　　金：国防创新基金资助项目(No.CXJJ-259)

摘　　要：给出一种上下文自适应的游程编码和扩展指数哥伦布编码。利用游程编码算法对图像小波系数及ROI掩模进行上下文自适应建模并输出三元组样本;然后扩展普通的指数哥伦布编码,使其可以编码由游程编码建模输出的三元组样本,在对小波系数编码的同时可以携带感兴趣区域掩模标记信息。由此得到一种可以区别感兴趣区域和背景区域的高效编码算法,并以此算法为基础提出一种感兴趣区域编码的编解码框架,该框架包括5/3小波变换、小波域掩模标记生成、不均匀最佳量化、游程编码和扩展的指数哥伦布编码。该算法的游程建模过程简单,熵编码算法可用闭合公式表达,具有较高的可实现性。实验结果表明,提出的算法支持多个任意形状的感兴趣区域,感兴趣区域相对于背景区域的编码优先级可调,并且可以获得高于基于BbB-shift的SPIHT算法的压缩性能。A context adaptive tri-element Run length coding algorithm and an Exp-Golomb coding alogorithm were introduced.The Run-length coding was used to model the image wavelet coefficients and the Region of Interest（ROI） mask and to yield tri-element codes.Then,the conventional Exp-Golomb coding was expanded to encode tri-element codes from Run-length coding and to carry the ROI mask together.Based on the two algorithms above,a high efficient algorithm to distinguish the ROI and background was obtained and a ROI codec framework was proposed.The framework includes 5/3 wavelet transform,wavelet domain mask generation,non-uniform optimal quantization,context adaptive tri-element Run-length coding and generalized Exp-Golomb coding.The tri-element Run-length coding in this algorithm is brief,and the expanded Exp-Golomb coding can be expressed by a closed formula.Experimental results show that the algorithm supports multiple arbitrary-shaped ROI and the adjustability of the ROI is prior to that of the background region.Furthermore,it achieves higher compressing performance as compared with the BbB-shift based SPIHT compression algorithm.

关 键 词：图像编码 感兴趣区域编码 自适应游程编码 指数哥伦布编码 

分 类 号：TN919.81[电子电信—通信与信息系统]