文档介绍：八方向滤波器的设计及其在图像增强中的应用
张洁杨丰
(南方医科大学生物医学工程学院,广州,510515,jiezhang@)
摘要: 本文提出一种无抽样的方向滤波器组设计方法。该方法是在文献[1][3]基础上,将多级滤波器组整合为单级滤波器组,并将其转化为的空间模板,与图像卷积可获得八方向的子带图像,各子带图像尺寸大小与原图像相同,利用各方向子带统计特性,实现图像增强。实验结果表明:本方法因避免了抽样与插值过程,操作简便。采用图像方向特征,降低图像模糊影响,图像增强效果明显。
关键词: 无抽样方向滤波器组;滤波器设计;图像增强;图像处理
Design of eight-band directional filter and its application in image enhancement
ZHANG Jie YANG Feng
(Biomedical engineering department of Southern Medical University,Guangzhou 510515)
Abstract: This paper presents a decimation-free directional filter bank. We integrate multilevel filter banks into single level filter bank based on paper[1][3], and transform each directional filter into an operator with size of . We can convolve image with the operator to get eight subband images of the same size as the original input image. We get enhanced image according to the statistic character of block centered of each pixel in each subband image .Results proved that because of avoiding downsampling and upsampling, it es easy to handle, and reduce the influence of gray using directional information.
Keywords: decimation-free directional filter bank; design of filter; image enhancement; image processing
1 引言
方向滤波器作为图像方向特征描述的重要工具,其广泛应用于图像压缩、增强、边缘检测和去噪等图像处理。比如,在经典边缘检测算法中,Sobel算子、Prewitt算子和LoG算子,以及小波变换均可归属于方向滤波器,但它们都仅限于水平、垂直和对角方向。Bamberger和Smith于1992年首次提出了多方向滤波器组设计[1],每个子带输出都具有特定方向性。因对原始图像进行多倍抽样,造成各子带图像分辨率与原图像不同,并随