具有任意方向的扇形滤波器及其在图像方向检测中的应用

扇形滤波器在图像的方向检测中是非常重要的.本文基于极傅里叶变换和一个楔形滤波器,设计出具有任意方向的二维扇形滤波器.首先,楔形滤波器被变换到极傅里叶域,再利用极傅里叶变换的旋转特性,楔形滤波器可以通过将其极傅里叶变换沿着水平方向进行移动来实现旋转,得到一系列具有任意方向导向的扇形滤波器,它们能够检测图像中所包含的任意方向信息.由于整个设计过程不涉及二维优化,因此所提出的设计方法具有设计简单的优点.为了验证扇形滤波器的方向敏感性,将所设计的扇形滤波器应用于图像的纹理方向检测,结果表明,具有任意方向的扇形滤波器在图像纹理方向检测中具有很大的潜能.

Arbitrarily-orientated Fan Filter and Its Application in Direction Detection of Images

Fan filter palys an important role in direction detection of images. In this paper, a simple but efficient method is proposed for the design of two-dimensional (2D) fan filters with arbitrary orientations. The proposed method is based on the polar Fourier transform (PFT) and a wedge-shaped filter. Firstly, the wedge-shaped filter is transformed to the polar Fourier domain. Then, by taking the rotation advantage of PFT, this wedge-shaped filter is rotated via shifting its PFT along the horizontal axis. By doing so, a series of arbitrarily-orientated fan filters are obtained and these obtained fan filters can detect the image information in arbitrary directions. Furthermore, since the design process involves no 2D optimization, the advantage of easy design is also achieved. To varify their directional sensetivity, the designed fan filters are applied to detect the texture direction of images. Experiment results show that the proposed fan filters has great potential in texture detection.