An Improved Method for the Calibration of a 2-D LiDAR With Respect to a Camera by Using a Checkerboard Target
Fumio Itami, Takaharu Yamazaki
Abstract
This paper proposes an improved method for the calibration of a 2D LiDAR or a planar scanning laser rangefinder with respect to a camera, which uses the same checkerboard target as in the camera calibration. To address one of the drawbacks in the LiDAR calibration with a checkerboard, the sensitivity to checkerboard poses, laser points on the checkerboard are obtained from both the originally positioned LiDAR and the same LiDAR vertically rotated from the original position, in the proposed calibration. They construct the additional constraints with the normal vector of the checkerboard, and strengthen the basic point-on-plane constraints in the LiDAR calibration with a checkerboard. However, in practice, the LiDAR rotation can be imprecise. Thus, we further develop the calibration procedure and examine its calibration performance, in the presence of such impreciseness in the LiDAR rotation. A performance analysis is conducted with synthetic noisy data, and it is confirmed that the proposed calibration yields smaller error in the parameter estimation than a conventional baseline calibration method. Subsequently, we examine the calibration performance with real data, where the proposed calibration is carried out by building a calibration system. It is shown that the proposed calibration also has more consistency in the parameter estimation. For further study, we compare the proposed calibration based on point-on-plane constraints with a calibration based on point-to-point constraints, and show that the proposed calibration, with easier data acquisition, yields comparable results.