摘要
为了校正强反射表面图像的亮度不均匀性,抑制局部强亮度现象,同时使其保留足够多的原始图像信息,研究了强反射表面缺陷图像的预处理方法。分析了强反射表面的光学特性,研究了偏微分方程理论及同态滤波算法,在此基础上提出了一种基于偏微分方程的同态滤波算法,即采用热传导方程滤波算子对同态分解的图像进行处理。引入信息熵对不同尺度参数下的处理效果进行评价,从而确定热传导同态滤波的尺度参数,并将该算法与背景去除法、基于小波的同态滤波算法进行了比较。对比实验表明,采用提出的算法处理后得到的图像其灰度级均匀分布在1～6之间,信息熵值均在91%以上。该方法校正了图像亮度的不均匀性,提高了图像质量,同时能保留足够多的原始图像信息。
In order to modify the luminance heterogeneity of a highly reflective surface image, restrain the phenomenon of local high luminance and to preserve enough original image information,a preprocessing method for highly reflective surface defect image is investigated and the optical characteristics of a highly reflective surface are analyzed by using Partial Differential Equation （PDE） theory and homomorphic filtering algo- rithms. A homomorphic filtering algorithm based on the PDE is proposed which uses the heat conduction equation filtering operator to process homomorphic decomposition images. The comentropy is induced to evaluate the processing effect in different dimension parameters, then the dimension parameter of heat conduction homomorphic filtering is determined. The algorithm is contrasted with the background Subtraction algorithm and wavelet homostasis filtering algorithm,and the experiment indicates that the image processed by the proposed algorithm has the gray level values distributed uniformly between 1-6 and a high comentropy value above 91%. This method modifies the image luminance heterogeneity, improves image quality and preserves sufficient original image information.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2010年第10期2288-2296,共9页
Optics and Precision Engineering
基金
国家863高技术研究发展计划资助项目(No.2007AA041501)
国家重大科技专项课题资助项目(No.2009ZX04004-062)
关键词
强反射表面
缺陷图像
图像预处理
偏微分方程
同态滤波
highly reflective surface
defect image
image preprocessing
Partial Differential Equation （PDE）
homomorphic filtering
