Real-time ground filtering algorithm of cloud points acquired using Terrestrial Laser Scanner (TLS)

•Fast and precise ground filtering is a key problem in point cloud understanding.•K-nearest neighbor search is usually a bottleneck algorithm of ground filtering.•Kd-tree and parallel processing boost the k-nearest neighbor search.•Principal component analysis and the RANSAC algorithm are potent tools to find flat regions.•A voxel structure might reduce the computation time or nearest neighbors.