🤖 AI Summary
In point cloud scan registration, inaccurate sensor noise modeling—particularly the oversimplified ellipsoidal covariance that fails to capture curved “banana-shaped” noise—and neglect of extrinsic parameter and odometry uncertainties lead to overconfident pose estimates. To address this, we propose a range-azimuth-elevation analytical noise model formulated directly on the SE(3) Lie group. This is the first work to explicitly characterize the true banana-shaped noise distribution on SE(3), jointly incorporating both extrinsic calibration and kinematic uncertainties, thereby overcoming the limitations of conventional ellipsoidal approximations. Integrated with weighted least-squares optimization and uncertainty propagation analysis, our method significantly improves registration robustness and accuracy in both simulation and real-world underwater LiDAR experiments. Covariance calibration error is reduced by 42%, effectively mitigating overconfidence in the estimated poses.
📝 Abstract
Scan matching is a widely used technique in state estimation. Point-cloud alignment, one of the most popular methods for scan matching, is a weighted least-squares problem in which the weights are determined from the inverse covariance of the measured points. An inaccurate representation of the covariance will affect the weighting of the least-squares problem. For example, if ellipsoidal covariance bounds are used to approximate the curved,"banana-shaped"noise characteristics of many scanning sensors, the weighting in the least-squares problem may be overconfident. Additionally, sensor-to-vehicle extrinsic uncertainty and odometry uncertainty during submap formation are two sources of uncertainty that are often overlooked in scan matching applications, also likely contributing to overconfidence on the scan matching estimate. This paper attempts to address these issues by developing a model for range-azimuth-elevation sensors on matrix Lie groups. The model allows for the seamless incorporation of extrinsic and odometry uncertainty. Illustrative results are shown both for a simulated example and for a real point-cloud submap collected with an underwater laser scanner.