基于小波变换的预测四叉树图像编码  

Predictive quadtree coding based on wavelet

作　　者：冯前进[1] 梁斌[1] 秦安[1] 袁静[1] 陈武凡[1] 

机构地区：[1]南方医科大学生物医学工程学院,广东广州510515

出　　处：《电路与系统学报》2006年第3期36-41,共6页Journal of Circuits and Systems

基　　金：973基金项目(2003CB716104);国家自然科学基金重点资助项目(30130180);广东省科技计划资助项目(2003B30605)

摘　　要：本文提出了一种图像编码的新算法,该算法利用了图像小波系数在频带内部与频带间的相关性,属于带内编码与带间编码的混合。在同一频带内将系数分块,随比特面的移动,将块由大到小进行四叉树分裂,以期最大限度的利用块内系数的相关性,克服了固定大小块的不足。同时在编码的过程中加入了预测过程,用上一比特平面的显著系数在当前比特面对其邻域和子节点系数进行预测,将上一比特平面的显著系数的邻域和子节点系数从块中取出单独编码,从而实现对块的裁剪,以使块的形状更符合实际的情况。最后熵编码采用的了基于上下文的算术编码,提出了四种上下文编码模型。通过对比实验表明,该方法的压缩性能较SPIHT、SQP、QT_L均有不同程度的提高。A new Wavelet Image Coding method based on Predictive Quadtree-split is proposed in this paper. This method hybridizes the intra-band and inter-band coding. Wavelet coefficients in same band are partitioned into many blocks, and the blocks are split according to quadtree with the moving of bitplane. This kind of dynamic block splitting can overcome some shortcomings brought by fixed block size. At the same time, the algorithm introduces a predictive coding procedure to truncate the block and make the block＇s shape fit in with the actual image. A context based arithmetic coder is adopted in entropy coding, and four different sets of models are designed for the arithmetic coder. The experiment results show that the proposed algorithm provides better compression ratio than SPITH, SQP, QT_L.

关 键 词：小波变换 图像编码 SPIHT SQP 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]