一种新的方向滤波器组及其在图像去噪中的应用

通过将二维棋盘形滤波器对和二维余弦调制滤波器组相结合，构造了具有方向和频率选择性的新的方向滤波器组。本文中，我们首先设计了具有45度和135度方向的二维棋盘形滤波器对。通过棋盘形滤波器对，输入图像首先被分解为两幅图像。然后，二维余弦调制滤波器组被分别应用到每幅图像。这种结构等效于一个冗余比为2的方向滤波器组。新的滤波器组具有良好的方向和频率选择性。作为新滤波器组的一个应用，我们把双重局部维纳滤波算法和新的方向滤波器组相结合，提出了一种新的图像去噪算法。实验结果表明：对于具有丰富纹理的图像，提出的算法获得了明显的去噪性能改善。

New Directional Filter Bank and its Application in Image Denoising

This paper constructs a new directional filter bank (DFB) by cascading checkerboard- shaped filter pair and cosine modulated filter bank (CMFB). We first design a checkerboard-shape filter pair with directions 45 degree and 135 degree to decompose the input image into two images containing different directional information of the original image. Next, a 2-D separable CMFB is applied to the two images to realize subband decompositions. This cascading structure corresponds to a new directional filter bank of redundant ratios of 2. The new DFB can provide good directional and frequency selectivity. As an application of the new DFB, we combine the new DFB and the doubly local Wiener filtering algorithm to develop a new image denoising algorithm. The experimental results show that the proposed algorithm achieves satisfactory performance improvement for images with abundant textures.