Extrinsic Calibration of Multiple LiDARs for a Mobile Robot based on Floor Plane And Object Segmentation

TL;DR

A target-less extrinsic calibration method for multiple LiDARs with non-overlapping fields of view (FoV) that achieves higher accuracy in extrinsic calibration with two and four LiDARs compared to conventional methods, regardless of the type of objects.

Abstract

Mobile robots equipped with multiple light detection and ranging (LiDARs) and capable of recognizing their surroundings are increasing due to the minitualization and cost reduction of LiDAR. This paper proposes a target-less extrinsic calibration method of multiple LiDARs with non-overlapping field of view (FoV). The proposed method uses accumulated point clouds of floor plane and objects while in motion. It enables accurate calibration with challenging configuration of LiDARs that directed towards the floor plane, caused by biased feature values. Additionally, the method includes a noise removal module that considers the scanning pattern to address bleeding points, which are noises of significant source of error in point cloud alignment using high-density LiDARs. Evaluations through simulation demonstrate that the proposed method achieved higher accuracy extrinsic calibration with two and four LiDARs than conventional methods, regardless type of objects. Furthermore, the experiments using a real mobile robot has shown that our proposed noise removal module can eliminate noise more precisely than conventional methods, and the estimated extrinsic parameters have successfully created consistent 3D maps.

Figures (11)

• Figure 1: The proposed method achieves extrinsic calibration of multiple LiDARs with non-overlapping FoV such as mobile robot in (a). Our approach is accumulating data while moving similar to (b) and creating a common FoV to evaluate the consistency of the 3D map. The proposed method achieves accurate extrinsic calibration and generates a consistent 3D map even when most of the observations are on the floor, shown in (c).
• Figure 2: System overview of proposed multiple LiDAR calibration method
• Figure 3: Scanning pattern of a non-repetitive LiDAR
• Figure 4: Movement trajectory and extrinsic parameter refinement with planes
• Figure 5: Configuration of multiple LiDAR and environment in simulation. (a) The LiDARs are divided into two sets: Set 1 (red) with two LiDARs and Set 2 (green) with four LiDARs, each arranged to avoid overlap. (b) These LiDARs are moved in an environment where objects with a height of 0.25 m are placed around.