摘要
针对复杂曲面特征测量时十字结构光的快速、高精度标定,提出一种基于直线空间旋转的十字结构光标定方法。利用OTSU算法选取最佳阈值来提取光条的所在区域,通过基于Hessian矩阵的Steger算法和最小二乘法提取并拟合光条中心;通过图像中与靶标平面内特征点对的构建,借助RANSAC算法求解单应性矩阵,对光条直线进行单应性矩阵变换来获取靶标平面内的光条直线方程;由相机坐标系与世界坐标系的转换关系,将直线方程转换到相机坐标系下;由空间直线绕任意轴的旋转变换关系,将光条直线绕投射中心线进行旋转,并将旋转前后的两条直线进行平面拟合,求解光平面方程参数。结果表明,该方法对靶标圆心间距测量的平均绝对误差为0.023 mm,均方根误差为0.026 mm。本文方法可以实现较高的测量精度,且能避免靶标平面的多次移动。
Aiming at the rapid and high-precision calibration of cross structured light in the measurement of complex surface features,we propose a cursor calibration method for the cross structured light based on lin⁃ear space rotation.We used the Otsu thresholding algorithm to select the best threshold for extracting the area where the light bar was located,and the Steger algorithm based on the Hessian matrix and the least square method were able to extract and fit the center of the light strip.After the construction of feature point pairs in the image and the target plane,the random sample consensus(RANSAC)algorithm was used to solve the homography matrix,and a straight line was transformed to obtain the linear equation of the light bar in the target plane.The straight line was then converted into the camera coordinate system.From the rotation transformation relationship of the space straight line around any axis,the light strips were rotated around the projection centerline,and the two straight lines before and after the rotation were plane fitted to solve the light plane equation parameters.The results showed that the average error when using this method to measure the distance between the target centers was 0.023 mm and that the root mean square error was 0.026 mm.This method can achieve higher measurement accuracy and can avoid multiple movements of the target plane.
作者
秦训鹏
丁吉祥
董寰宇
董书洲
QIN Xun-peng;DING Ji-xiang;DONG Huan-yu;DONG Shu-zhou(Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan University of Technology,Wuhan 430070,China;Hubei Research Center for New Energy&Intelligent Connected Vehicle,Wuhan University of Technology,Wuhan 430070,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2021年第6期1430-1439,共10页
Optics and Precision Engineering
基金
国家重点研发计划(No.2018YFB1106500)
湖北省技术创新专项(No.2019AAA075)
中国博士后科学基金(No.2020M682498)。
关键词
十字结构光
光平面标定
单应性矩阵
直线空间旋转变换
计算机视觉
cross structured light
light plane calibration
homography matrix
linear space rotation trans⁃formation
computer vision
