一种基于摄影测量的自动分拣系统标定方法

Aphotogrammetry-based Approach to Automatic Sorting System Calibration

针对6轴工业机器人自动分拣系统,提出了一种新的标定方法。该方法由工作相机对置于传送带上的平面靶标拍摄一幅图像,据此计算工作相机与平面靶标之间的单应性矩阵,运用摄影测量系统对传送带上的平面靶标及散布于机器人表面的标记点拍摄机器人绕A4轴做一次旋转运动前后的2组图像,再拍摄机器人绕其A1轴做一次旋转运动前后的2组图像,在对每组图像中的目标点分别进行三维重建的基础上,得到机器人坐标系以及平面靶标与机器人坐标系的位置关系,进而结合计算出的单应性矩阵得到工作相机图像平面至机器人坐标系的映射,实现自动分拣系统的标定。经实验验证,具有较高的标定精度。

A new calibration approach to automatic sorting system with six DOF robot is proposed.In the calibration process,one image of the planar target on the conveying belt is taken by the working camera,then the image taken is used to calculate the homography between the working camera and the planar target.The robot rotates around its A4 axis once,and a group of images of the visual markers scattered on the robot before and after the rotation are taken by the photogrammetry camera respectively.Then the robot rotates around its A1 axis once,and a group of images of the planar target and the visual markers scattered on the robot before and after the rotation are taken by the photogrammetry camera respectively.Based on the 3D reconstruction results of the two groups of images,the coordinate system of the robot is established and the geometric relationship between the planar target and the robot is achieved.Combined with the homography calculated,the transformation matrix between the working camera image plane and the robot coordinate system is implemented to completes the whole calibration.Experiments show that the proposed method is of high calibration accuracy.