Laser Based Online Sliding Window Approach for UAV Loop Closure Detection in Urban Environments
Online loop closure detection serves as an essential task for Unmanned Aerial Vehicles (UAVs) equipped with laser scanners. Due to the inherent errors in UAVs' pose estimation, a 3 D reconstruction algorithm is adopted to perform 3 D map building, which establishes probabilistic models of the system according to the assumption of errors. To meet the demand of online loop closure detection using sequential 2 D laser data, a robust ISW NDT (incremental sliding window based NDT) approach is proposed, which compares the appearance similarity between two scans by sliding a window with fixed size. Compared with the conventional 3 D NDT approach, the proposed loop closure detection algorithm is capable of providing superior performance in large scale outdoor environments, achieving higher recall rate at 100% precision and ensuring successful online implementation. Experimental results show the validity and robustness of the proposed method.