基于垂直约束的激光扫描机构外参标定算法

The External Calibration Algorithm for Plane Laser-Scanning Machanism Based on Vertical Constraint

为了解决人造特征点标定法中特征匹配不精确等缺陷,本文针对二轴传动的高精度平面激光扫描机构提出了利用线特征的垂直约束进行外参标定的新算法.不仅如此,在该算法中为了简化建立标定方程的流程,避免计算与标定目标无关的冗余中间量,提出了一种快速确定标定方程参数的方法.首先将扫描结果按待标定参数标准值转换至同一坐标系形成点云,再提取其中的线特征;接着根据线特征的垂直约束建立外参方程,并根据线特征的测量值和实际值间的转换计算方程参数;最终,将多次测量得到的方程组求解转化为最优化问题,并得到外参的数值解.在对比实验中,本算法比基于特征点的标定方法表现更好.

In order to solve the defect of inaccurate feature matching in the artificial feature point calibration method,a new algorithm for the external parameter calibration using the vertical constraint of line feature for the plane laser-scanning machanism of high precision two-axis transmission is proposed in this article.Moreover,in this algorithm,in order to simplify the process of establishing the calibration equation and avoid calculating the redundant intermediate quantity unrelated to the calibration target,a method for quickly determining the parameters of the calibration equation is proposed.Firstly,the scan result is converted to the same coordinate system according to the standard value of the parameter to be calibrated to form a point cloud,and then the line features are extracted;then the external parameter equation is established according to the vertical constraint of the line feature,and the parameters of the equation is calculated according to the conversion between the measured value and the actual value of the line feature;finally,the equations obtained from the multiple measurements are transformed into optimization problems,and the numerical solution of the external parameters is obtained.In the contrast experiment,the algorithm performs better than the feature point based calibration method.