High precision calibration method of laser projection turntable

Camera calibration is the bridge between 2D image and 3D world and is the basis of 3D stereo vision. Camera calibration can establish the mapping between the real 3D coordinates of space points and the corresponding 2D coordinates of the image. It will directly affect the final effect of 3D reconstruction or the positioning accuracy of 3D coordinates of space points. So accurate camera calibration technology is an essential step in 3D reconstruction, target spatial localization and even all machine visual systems, which has very important research significance. However, in some special scenarios, traditional calibration methods are difficult to use because of the long distance or difficulty in entering the scenario. To solve this problem, we propose a calibration method based on laser projection turntable. The camera shoots the laser projection lattice to determine the corresponding relationship between the pixel coordinates and the motor code amount, which is put into the calibration model to complete the camera calibration. Before camera calibration, the laser projection turntable must be calibrated with high accuracy. Firstly, the initial pose of the laser projection turntable is estimated. We accurately obtain the 3D coordinates of the calibration points with the help of the total station, and the pose information of the laser projection turntable is obtained by rigid body transformation, and then the corresponding relationship between the projection point and the code amount of the motor is obtained. Then, the least square method is used to optimize the estimation to improve the calibration accuracy. The experimental results show that the method meets the requirement of calibration accuracy and has practical application value, and the implementation of the subsequent camera calibration method can be continued.