数字图像相关方法在桥梁裂缝变形监测中的应用

Application of Digital Image Correlation Method in Bridge Cracks Measurement

本文结合工程实际背景分析了数字图像相关方法应用在桥梁裂缝变形监测中的可行性及优越性,根据桥梁裂缝变形的特点采用数字图像处理技术中的位移梯度法进行所选区域的相关匹配搜索并对相关系数的计算公式加以改进,使实验过程得以简化,计算结果全场化、直观化。本文对数字图像处理软件的测量精度和在实际测量中的测试误差进行了分析和研究,证明该软件能够更加精确地测定裂缝在各种荷载作用下的变形量值。实际的桥梁测试也验证了该方法的可行性和优越性。若图像记录设备的分辨率是12.47pixel/mm(0.0802mm/pixel),本文所涉及到的桥梁裂缝边缘的位移测试精度为0.000802mm。

The feasibility and advantage of digital image correlation used for the deformation measurement of bridge cracks was analyzed referring to the practical background of engineering. According to the deformation characteristic of bridge cracks the displacement gradient method of digital image technology was adopted for correlation search and the equation of correlation coefficient was improved. The technique can make the course of experiment simplified and the results visible. The measurement error of DIC software is also discussed and the results are more accurate. The deformation measurement process of actual cracks of bridge has verified these views above. If the distinguish ability of image grabber is 12.47pixel/mm, the precision of displacement measurement can achieve 0.000802mm.