一种改进的Curvelet变换算法  

Modified Algorithm for Curvelet Transform

作　　者：马丽红[1] 麦棣科[1] 罗骁茜[1,2] 卢汉清[3] 

机构地区：[1]华南理工大学电子与信息学院,广州510641 [2]广东省移动通信公司佛山分公司,广东佛山528000 [3]中国科学院自动化所国家模式识别重点实验室,北京100080

出　　处：《数据采集与处理》2009年第1期7-13,共7页Journal of Data Acquisition and Processing

基　　金：国家自然科学基金(60472063)资助项目;广东省自然科学基金(04020074)资助项目

摘　　要：提出一种Curvelet变换的改进方法。该方法对经典算法进行了两方面改进:保持较大尺度下高频子带各子块的投影轴数不变,在较细尺度下减少投影方向数,使计算量下降;为保持原信号分辨率,对图像平滑块和边缘块分别进行插值和边缘主方向投影补偿。子块类别和边缘子块主方向用8区域方向滤波器来确定。实验结果表明,与降采样下的8方向经典算法相比,改进算法的PSNR值提高约0.8 dB;实现变换的平均耗时比16方向非降采样经典算法减少约9%。在主观视觉效果上,改进算法的重建图像和16方向经典算法结果接近,但系数冗余更小。当折衷考虑变换的耗时、重建质量和系数表达的紧凑性时,改进算法占有明显优势。An algorithm for rapid and efficient Curvelet transform is proposed. The algorithm modifies the original algorithm in two aspects. Firstly, the number of projecting axes in finer scales is decreased, while axis numbers in coarser scales remain are unchanged. Secondly, to maintain the signal resolution, the interpolation and the additional projection are introduced into smooth blocks and edge blocks. Additionally, directional filter banks are utilized to deter- mine the dominant orientations in edge blocks. Experimental results reveal that the modified algorithm increases PSNR about 0.8 dB, and save 9% of the average computational time com- pared with the conventional algorithm. The new algorithm can obtain similar visual quality with less redundance. It is superior to the original Curvelet transform in a tradeoff between the image quality and runninng time.

关 键 词：CURVELET变换 脊波分析 插值 主方向投影 8区域方向滤波器 

分 类 号：TN911[电子电信—通信与信息系统]