一种线结构光平面的标定方法

A method for calibrating the light plane of the linear structured light

为了线结构光平面标定的准确性和高效性,以及提高线结构光平面标定方法的普适性,提出了一种基于2维圆形标靶的线结构光平面标定方法。采用光条提取算法得到照射在2维圆形标定靶任意位置处光条中心点的亚像素坐标值,将光条上所有点拟合成直线,交圆形标定靶每列靶标连线于一点;得到每列靶标连线与拟合出的光条中心线交点后,连接交点与相机光学中心形成一条直线;联立该连线的直线方程与像素坐标系下两条交线的直线方程,以及2维圆形标定靶所在平面的方程,求解出每个交点在相机坐标系下的坐标;最后采用最小二乘拟合算法进行平面拟合,得到了所求光平面方程;介绍了该标定方法的基本原理和实现过程,搭建实验系统对其有效性进行了验证。结果表明,用该方法求取光平面的平均测量误差可以达到2.36737 mm,鲁棒性高,且标定流程十分简便,适用于一般的工程应用和机械加工过程。该研究为线结构光传感器的光平面标定提供了参考。

In order to improve the accuracy and efficiency of line structure light plane calibration and the universality of the calibration method,a line structure light plane calibration method based on a 2-D circular target was proposed.The subpixel coordinates of the center point of the light strip irradiated at any position of the 2-D circular calibration target were obtained by the light strip extraction algorithm.All the points on the light strip were fitted into a straight line,and the lines connecting each column of the circular calibration target intersected at one point.After obtaining the intersection point of each column of the calibration target line and the fitted light strip center line,a line connecting the intersection point and the camera optical center was formed.By setting up the equation of the line and the equations of two intersecting lines in the pixel coordinate system,and the equation of the plane where the 2-D circular calibration target was located,the coordinates of each intersection point in the camera coordinate system are solved.Finally,the plane fitting algorithm of least squares was used to obtain the equation of the light plane.The basic principle and implementation process of the calibration method was introduced,and the validity of the method was verified by setting up the experimental system.The results show that the average measurement error of the light plane obtained by this method can reach 2.36737 mm,which has high robustness,and the calibration process is very simple and suitable for general engineering applications and machining processes.This study provides a reference for the light plane calibration of line structure light sensors.