钢桥面板疲劳裂纹图像测量的激光测距自标定方法及系统  

Laser ranging self-calibration method and system used for image measurement of fatigue cracks in steel bridge decks

作　　者：黄斌 程斌[1] 周焕新 曾令博 HUANG Bin;CHENG Bin;ZHOU Huan-xin;ZENG Ling-bo(School of Naval Architecture,Ocean and Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学船舶海洋与建筑工程学院,上海200240

出　　处：《长安大学学报(自然科学版)》2025年第1期60-68,共9页Journal of Chang’an University(Natural Science Edition)

基　　金：国家重点研发计划项目(2021YFE0107800);中交集团院士专项科研经费项目(YSZX-03-2021-01-B)。

摘　　要：图像测量是钢桥面板疲劳裂纹检测的一种有效手段,但在相机图像标定时存在着无法设置标定物、标定辅助装置复杂、难以满足相机特殊位姿等问题,很难实现高精度实时动态标定。针对上述问题,提出一种可用于钢桥面板疲劳裂纹图像测量的激光测距自标定方法,该方法在拍摄裂纹图像时,利用高精度激光测距模块连续测量得到钢桥面板表面的实时位置信息,在此基础上对物面方程进行求解,获取物面和像面上4组对应点的二维坐标,求解得到表示2个平面之间变换关系的单应性矩阵,从而简便快速地完成实时标定;自主研发一套基于激光测距自标定的钢桥面疲劳裂纹图像测量系统,对钢桥面板典型区域开展自标定图像测量精度验证;并开展钢桥面板疲劳裂纹图像实测,通过灰度化、腐蚀膨胀、滤波去噪、二值化、提取连通域、中轴变换等图像处理方法方法提取出疲劳裂纹的图像特征点,结合标定结果实现对多种形状不规则裂纹的尺寸测量。研究结果表明:在自标定图像测量精度验证中,各区域中标尺长度的测量相对误差均在0.23%以内,验证了激光测距自标定方法具有较高的准确性和鲁棒性;在钢桥面板疲劳裂纹图像实测中,裂纹尺寸的测量值与真实值较为接近,测量相对误差均在1.35%以内,为该方法及系统在实际工程中的应用提供了参考。Image measurement is an efficient method to detect the fatigue cracks in steel bridge decks,while it is inconvenient to set calibration targets and auxiliary devices or to place the cameras in special poses during the image calibration process,and as a result high-precision,real-time,and dynamic calibration cannot be achieved.To address the above problems,a laser ranging self-calibration method used for the image measurement of fatigue cracks in steel bridge decks was proposed.This method employs high-precision laser rangefinders to synchronously measure the position of the steel plate surface when taking the crack pictures,so that the object plane equation can be determined.Then the 2D coordinates of four sets of points that have been selected respectively from the object plane and the image planes can be obtained,and the homography matrix which represents the mapping relationship between object and image planes can be solved,so that the real-time calibration can be completed simply and rapidly.A set of image measurement system for fatigue cracks in steel bridge decks based on laser ranging self-calibration was independently developed,and the accuracy verification of self-calibration image measurement was carried out in the typical areas of the steel bridge deck.Furthermore,the image measurement of fatigue cracks in the steel bridge deck was conducted.The image feature points of fatigue cracks were extracted by using image processing methods such as grayscale conversion,erosion and dilation,filtering and denoising,binarization,extraction of connected components and medial axis transformation.Combined with the calibration results,the size measurement of various cracks with irregular shapes was realized.The results show that in the accuracy verification of self-calibration image measurement,the measurement relative errors of the ruler's length in the typical areas are all within 0.23%,which indicates that the laser ranging self-calibration method is accurate and robust.In the image measurement of fatigue cracks in

关 键 词：桥梁工程 疲劳裂纹 图像测量 激光测距 钢桥面板 自标定方法 

分 类 号：U446[建筑科学—桥梁与隧道工程]