Rapid Calibration Method for 3D Laser Scanner

摘要

Background: The 3D laser scanner is a non-contact active-sensing system, which has anumber of applications. Many patents have been filed on the technologies for calibrating 3D laserscanner. A precise calibration method is important for measuring the accuracy of the 3D laser scanner.The system model contains three categories of parameters to be calibrated which include thecamera intrinsic parameters, distortion coefficients and the light plane parameters. Typically, thecalibration process is completed in two steps. Based on Zhang’s method, the calibration of the cameraintrinsic parameters and distortion coefficients can be performed. Then, 3D feature points on thelight plane should precisely be formed and extracted. Finally, the points are used to calculate thelight plane parameters.Methods: In this paper, a rapid calibration method is presented. Without any high precision auxiliarydevice, only one coplanar reference target is used. By using a group of captured images of thecoplanar reference target placed in the field of view arbitrarily, calibration can be performed in onestep. Based on the constraint from the planes formed by the target in different directions and thecamera imaging model, a large amount of 3D points on the light plane can easily be obtained. Thelight plane equation in the camera coordinates system can be gathered by executing plane fitting tothe 3D points.Results: During the experimental process, the developed 3D laser scanner was calibrated by theproposed method. Then, the measuring accuracy of the system was verified with known distance invertical direction of 1mm with sequential shifting motion generated by precision translation stage.The average value of the measured distances was found to be 1.010mm. The standard deviation was0.008mm.Conclusion: Experimental results prove that the proposed calibration method is simple and reliable.