全相位方向滤波器组设计及其应用

为提高方向滤波器组的方向选择性和运算速度，基于全相位列率滤波理论提出了一种新的方向滤波器组设计方法该方法直接从频谱特性设计纯二维方向滤波器并灵活构建方向滤波器组，避免了传统方向滤波器组对图像的旋转、采样等操作，可以更多地保留图像细节并减小运算量．采用该方法设计了2种全相位方向滤波器组，并将其用于图像去噪对经典测试图像的实验结果表明，与Contourlet变换及其改进——非下采样Contourlet变换相比，采用该方法去噪后图像的峰值信噪比最多提高2．96dB，且重建图像的主观质量也较好．

Design and Application of All Phase Directional Filter Bank

To improve the directional selectivity and efficiency of directional filter bank,a novel designing approach of directional filter bank based on all phase sequency filtering theory was presented. In all phase datum space,pure 2-D directional filters were designed directly from its spectrum and directional filter banks were flexibly constructed without rotation and resampling of image necessary in traditional directional filter banks,so as to preserve more image details and reduce computational complexity. Two all phase directional filter banks were designed based on this method and used in image denoising. Experimental results demonstrate that compared with Contourlet and nonsubsampled Contourlet,the PSNR of the images reconstructed by proposed algorithm is superior up to 2.96 dB and the images are also of better subjective quality.