基于单像摄影测量的桥梁裂缝快速测量方法

Bridge Crack Rapid Measurement Method Based on Single Image Photogrammetry

针对传统桥梁裂缝量测操作复杂、效率差、危险性高的现状,提出了一种基于单像摄影测量的桥梁裂缝快速测量方法。首先使用数码相机采集桥梁裂缝的单张影像;其次利用Levenberg-Marquardt算法进行相机标定并完成原始影像的畸变纠正;然后使用Wong-Ttrinder圆点定位算子自动定位出标志牌上标志点的中心位置并进行二维直接线性变换,实现影像平面坐标与物方空间坐标之间的转换;最后采用基于卡方检验的Canny边缘检测算子精确提取出裂缝边缘,并实现裂缝宽度的自动量测。实验结果表明,与裂缝测宽仪量测结果相比,本文方法的中误差为0.25 mm,相对误差的范围为0.15%~0.37%,能够满足桥梁裂缝监测工程的要求,在实际的应用中具有较强的鲁棒性、经济性与安全性。

Considering the complex process, low efficiency and high risk of regular bridge crack measurement, a bridge crack rapid measurement method based on single image was proposed. Firstly, single image of bridge crack was captured using a digital camera;Then,the image was calibrated using camera calibration model based on Levenberg-Mar-quardt algorithm. Thirdly, after automatic positioning the centers of marks at Reflective targets, transformation between im-age coordinate system and space coordinate system was constructed using 2D direct linear transformation algorithm. Final-ly, after detecting and extracting the edge of bridge crack by chi - square test - based canny edge detector, the width of crack was calculated automatically and precisely. The experimental results show that standard deviation is 0.25mm and relative error ranges from 0.15% ？0.37%,which are measured between our method and crack micrometer method. The rseults demonstrate that our method can meet the need of bridge crack monitoring engineering and can be used in practical application with stronger robustness,low cost and high safety.