受电弓滑板磨耗检测中多视觉传感器标定方法研究

Research on the calibration method of multi-vision sensors in the wear detection of pantograph skateboard

受电弓磨耗缺陷作为受电弓最主要故障缺陷,但由于碳滑板横向尺度大、边缘精度低等特点,单个视觉传感器不能覆盖到所有受电弓轮廓,因此提出一种利用多视觉传感器进行全局标定的标定方法。首先,使用二维靶标对单个视觉传感器进行标定得到摄像机内部参数,然后对激光平面进行标定和求解,最后把三维靶标置于相邻两个摄像机的交叉视角范围内,并求解出两个相邻相机的外部参数。综合摄像机内外部参数和光平面方程即可建立统一坐标系下的数学测量模型,当得到线结构光测量模型后将二维图像的特征点转换为空间点云信息即可实现对滑板磨耗的测量。该系统通过测量三维靶标的尺寸并和真实距离进行对比来验证测量模型的准确性。对比结果表明该方法标定精度高、实现简单、结构稳定,能够有效用来对受电弓碳滑板磨耗的测量。

The pantograph wear defect is the main fault defect of the pantograph.However,due to the large lateral scale and low edge accuracy of the carbon slide plate,a single vision sensor cannot cover all the pantograph contours.Therefore,a method of using multiple vision sensors is proposed.The calibration method of global calibration.First,use a two-dimensional target to calibrate a single vision sensor to obtain the internal parameters of the camera,and then calibrate and solve the laser plane.Finally,place the three-dimensional target within the cross-view range of two adjacent cameras,and solve the two phases.The external parameters of the adjacent camera.Combining the internal and external parameters of the camera and the light plane equation can establish a mathematical measurement model under a unified coordinate system.When the linear structured light measurement model is obtained,the feature points of the two-dimensional image can be converted into spatial point cloud information to realize the measurement of the skateboard wear.Finally,the system verifies the accuracy of the measurement model by measuring the size of the three-dimensional target and comparing it with the real distance.The comparison results show that this method has high calibration accuracy,simple implementation,stable structure,and can be effectively used to measure the wear of the pantograph carbon sliding plate.