多方向照明下金属冲压字符图像融合算法  

Metal Stamping Character Image Fusion Algorithm Based on Multi-directional Illumination

作　　者：向忠[1] 张建峰 钱淼 吴震宇[1] 胡旭东[1] Xiang Zhong;Zhang Jianfeng;Qian Miao;Wu Zhenyu;and Hu Xudong(Faculty of Mechanical Engineering and Automation,Zhejiang Sci-Tech University,Hangzhou 310018)

机构地区：[1]浙江理工大学机械与自动控制学院,杭州310018

出　　处：《计算机辅助设计与图形学学报》2018年第9期1637-1642,共6页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家自然科学基金(51605443;U1609205);浙江理工大学校521人才项目

摘　　要：为增强金属冲压字符与背景之间的对比度,降低背景信息对字符分割的干扰,提高冲压字符分割的准确性和稳定性,提出一种基于多方向照明的图像融合算法.首先利用4个圆周均布的光源依次照明,分别采集4幅灰度图像;然后对采集到的图像进行背景均一化处理,消除单向光源照明下光照分布不均的影响;最后利用表面冲压凹陷区域与平坦区域在不同照明方向上的表面灰度变化特性,对2组相对照明方向上的背景均一化图像进行差值处理,实现图像融合,增强图像对比度.实验结果表明,与采用单光源照明方式相比,该算法可有效地消除油渍、锈蚀等背景干扰,增强冲压字符与同色背景之间的对比度,为冲压字符分割与识别奠定基础.Aim at enhancing the contrast between the metal stamping character （SC） and its background, to reduce the interference of the background information to improve the accuracy and stability of the SC seg- mentation, an image fusion algorithm based on multi-directional illumination is proposed. Firstly, four circumferentially uniform distributed light sources were adopted for acquiring images under different illu- mination directions by lighting up the lights one by one. And then a background homogenization process was implemented to eliminate the light intensity uneven distribution under unidirectional illumination. Finally, the reflection features at the depression area and the flat area were well studied and a mathematical model based on calculating the image gray differences of two images in opposite illumination direction was adopted to achieve image fusion and to enhance the image contrast. Experimental results show that the pro- posed algorithm can effectively eliminate the background interference, such as oil, corrosion and so on, and enhance the contrast between the SC and its background, lay the foundation for the segmentation and recog- nition of stamping characters.

关 键 词：冲压字符 多方向照明 图像融合 图像增强 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]