基于上下文选择编码的小波图像编码算法  

Coder selection based on context for wavelet image compression algorithm

作　　者：周映虹[1] 马争鸣[1] 

机构地区：[1]中山大学电子与通信工程系,广东广州510275

出　　处：《通信学报》2008年第1期132-140,共9页Journal on Communications

摘　　要：提出了基于上下文选择编码的小波图像编码算法:在独立同分布情况下,比较了直接对重要性信息进行算术编码、定长游程编码以及变长游程编码的理想平均比特损耗;分析了由于估计概率误差以及概率时变的存在从而导致了实际平均比特损耗增大;提出了新的上下文模型;根据上下文选择使用算术编码、定长游程编码或者变长游程编码。实验结果表明,在0.25bit/pixel下,新算法较算术编码方案编码时间节省了20%以上;与EBCOT相比,新算法提高了0～0.28dB;尤其适合于低码率应用。A wavelet image coding algorithm based on context selection was proposed： compares the ideal average coding cost of arithmetic coding, fixed run-length coding and variable run-length coding in the case of independently-identically distribution; analyses the increase of actual coding cost due to the existence of error of estimated probability and time-varying probability ; builds a new context template; chooses arithmetic coding, fixed run-length coding or variable run-length coding based on the proposed context model. Experimental results show that speed-up results are achieved in the new algorithm, for example, at 0.25bit/pixel, the proposed scheme saves 20% above coding time compared with arithmetic coding scheme; the proposed algorithm improves 0-0.28dB over embedded block coding with optimized truncation（EBCOT） in terms of PSNR and especially suits for low bit rate compression application.

关 键 词：小波图像编码 算术编码 定长游程编码 变长游程编码 

分 类 号：TN919[电子电信—通信与信息系统]