混凝土测试中光强对数字图像相关测量精度的影响研究  

Research on the influence of light intensity on digital image correlation measurement accuracy in the testing of concrete

作　　者：杨登辉 黄晨 樊平 吕健 韦鹏 杨立云[1] Yang Denghui;Huang Chen;Fan Ping;LüJian;Wei Peng;Yang Liyun(School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Key Laboratory for Old Bridge Detection&Reinforcement Technology of the Ministry of Transportation(Beijing),Beijing 100088,China)

机构地区：[1]中国矿业大学(北京)力学与建筑工程学院,北京100083 [2]旧桥检测与加固交通行业重点实验室(北京),北京100088

出　　处：《矿业科学学报》2023年第5期677-687,共11页Journal of Mining Science and Technology

基　　金：中央高校基本科研业务费(2022JCCXLJ01,2022YJSLJ04);旧桥检测与加固交通行业重点实验室(北京)开放课题(2020-JQKFKT-5)。

摘　　要：在复杂光照条件下采用数字图像相关技术(DIC)测量混凝土结构表面应变场时,光强变化会引起图像的退相关效应。针对此问题,基于传统2D-DIC测量系统,探究了光强变化对DIC测量精度与计算效率的影响规律。试验结果表明:平均灰度190为最优光强;以最优光强下的图片作为参考图像,光强增大时应变误差呈指数增长,光强减小时应变误差呈线性增长;计算时间与计算点匹配率对光强的小范围波动不敏感,但光强的剧烈变化会导致计算时间增加1~3倍以及25%的计算点匹配失败。结合图像质量评估指标,验证了实验结果的准确性。为了获得高质量的图像,本文建立了绿光带通滤波成像系统,该系统在外界环境光剧烈变化条件下依然能够保持图像的亮度与对比度基本不变,应变误差与计算效率均接近于最优光强。相对于传统2D-DIC测量系统,绿光带通滤波成像系统可较好地应用到室外环境测量。When the surface strain field of concrete structure is measured by digital image correlation(DIC)technology under complex light conditions,the decorrelation effect of the pattern will be caused by the variation in light intensity.For this problem,the optimal light intensity suitable for DIC calculating and analyzing is studied,and the influence of light intensity variation on the measurement accuracy and calculation efficiency of DIC is explored by the traditional 2D-DIC measurement system.The experimental result shows that the average gray level of 190 is the optimal light intensity.The picture is used as the reference image at the optimal light intensity.The strain error increases exponentially when the light intensity increases,and the strain error increases linearly when the light intensity decreases.The computation time and the matching rate of calculation points are insensitive to the slight range fluctuation of light intensity,while the computation time of DIC will increase 1 to 3 times,and about 25%of calculation points will match failed because of the extreme variation of light intensity.The accuracy of experimental results is verified by Combining them with the image quality assessment index.In order to get high-quality images,the green band-pass filter imaging system is established in this paper.It can stabilize the image􀆳s brightness and contrast when the external light varies seriously.The strain error and calculation efficiency are all close to the optimal light intensity when external ambient light changes seriously.Compared with the traditional 2D-DIC measurement system,The green band-pass filter imaging system can be better applied to measure in the outdoor environment.

关 键 词：数字图像相关技术 混凝土表面应变场 光强 图像质量 绿光带通滤波成像系统 

分 类 号：O348.1[理学—固体力学]