一种基于WBCT的图像编码算法  

An Image Coding Algorithm Based on WBCT

作　　者：聂永丹[1] 张岩[1] 唐国维[1] 

机构地区：[1]东北石油大学计算机与信息技术学院,黑龙江大庆163318

出　　处：《计算机技术与发展》2018年第1期74-77,共4页Computer Technology and Development

基　　金：黑龙江省研究生教育创新工程资助项目(JGXM-HLJ-2015111);黑龙江省教育科学规划重点课题(GJB1215019);东北石油大学青年基金(NEPUQN2014-20)

摘　　要：最新标准的图像压缩算法JPEG2000核心是在小波变换的基础上,利用率失真优化算法对所有码块的嵌入式压缩码流进行适当的截取,得到最优的编码率失真性能,提高编码性能。针对小波变换不能充分稀疏表示图像的二维几何特征,从而影响基于小波变换的传统图像压缩算法对图像纹理特征保持效果的问题,提出一种基于WBCT变换的EBCOT压缩算法。该算法利用基于小波的Contourlet变换可以有效地稀疏表示图像纹理区域的特性,根据码块熵最小化原则优化WBCT方向分解,降低了码块内系数的复杂程度,提高了EBCOT上下文模型编码效率;通过EBCOT自适应算术编码与率失真优化截断方法生成压缩码流。实验结果表明,重构图像不仅峰值信噪比(PSNR)得到提高,而且对图像局部纹理失真明显减小,证明了该算法的有效性。JPEG2000, a latest standard image compression algorithm, takes the proper interception of embedded bits stream for all code blocks by means of rate distortion optimization algorithm on the basis of wavelet transform and gets the optimal performance of rate dis- tortion for increasing of coding performance. In order to solve the problem that the wavelet transform cannot adequately represent the two -dimensional geometric features of the image, which affects the preservation of the texture area of traditional image processing algorithm based on wavelet transform, EBCOT （Embedded Block with Coding Optimized Transform）, a novel image coding algorithm based on WBCT （Wavelet-Based Contourlet Transform） ,is proposed. It can be sparse representation of the texture area of image effectively by Contourlet Transform based on wavelet and optimizes the decomposition of WBCT by the rule of code block entropy minimization,to re- duce the complexity of the coefficients in code block and improve the coding efficiency of EBCOT context model. Through the adaptive arithmetic coding of EBCOT and rate distortion optimization truncation method, the compressed bit stream is generated. The experimental results show that the reconstructed image not only improves the PSNR, but also reduces the distortion of local texture, which verifies its effectiveness further.

关 键 词：图像编码 小波变换 CONTOURLET变换 基于小波变换的Contourlet分析 最优截断嵌入码块 

分 类 号：TP13[自动化与计算机技术—控制理论与控制工程]