Visual positioning method based on line laser 3D measurement system

Abstract

To real time obtain the pose of a line laser sensor in a manipulator with a high accuracy, in this paper, a line laser three-dimensional(3D) measurement system is designed based on visual positioning method. First, the position and posture of the target in the camera coordinate system is obtained by the coplanar PNP model under isometric constraint and the absolute orientation problem. Second, the pose change matrices of the target relative to the initial position at different times are calculated by the pose of the target in the camera coordinate system to achieve the visual positioning. Third, the relative position and posture relationship matrix between the target and the line laser sensor is solved by the standard small ball method to achieve hand-eye calibration. Fourth, the measurement data of the line laser sensor are unified into the world coordinate system by the pose change matrices and the hand-eye calibration matrix to achieve the point cloud splicing. The experimental result shows that the displacement accuracy of the visual positioning is 0.039 mm, and the rotation accuracy is 4.2×10^-3 rad. The contour measurement accuracy of the line laser 3D measurement system based on the vision positioning technology is 0.55 mm. It can be seen that the system meets the general industrial measurement requirements.