基于消隐点的线结构光传感器光平面标定方法

Calibration Method for Line Structured Light Sensor Based on Vanish Points

光平面高精度标定是实现线结构光传感器精密测量的关键,提出一种基于消隐点的光平面标定方法。首先控制平面靶标或者传感器作一组平移运动,得到光平面中一组平行的激光条纹图像;然后通过提取光条与标定板网格线交点,构造出光平面中第二组平行直线,计算两组平行直线的消隐点并利用向量叉积标定光平面的法向;最后计算光平面上两特征点之间的实际距离,并根据这一约束条件,标定得到光平面方程的其余参数。通过与多种标定方法进行对比实验,结果表明本方法具有更高的标定精度,结合工业机器人对厚度为7 mm的标准量块进行测量,平均测量误差为0.013 mm。与基于两组平移运动的标定方法相比,本方法进一步减少了人工参与,提高了标定效率。

High precision calibration of the light plane is the key to the precise measurement for the line structured light sensor.A calibration method of the light plane based on vanish points is proposed.Firstly,a group of parallel laser stripe images are obtained by controlling the plane target or sensor to make a group of translation movement.Then,the second group of parallel lines in the light plane are constructed by extracting the intersection points of the light strip and the grid lines of the calibration board.The vanish points of the two groups of parallel lines are calculated and the normal direction of the light plane is calibrated by using the cross product of vectors.Finally,the remaining parameter of the light plane equation is solved by the actual distance between two feature points on the light plane.The experimental results show that the proposed method has higher calibration accuracy compare with same other traditional calibration methods,the average measuring error of the standard gauge block with the thickness of 7 mm is 0.013 mm measured by industrial robot.The proposed method further reduces manual participation compared with the calibration method based on two group of translation movements.