3D digitalization of environments without occlusions requires multiple 3D scans. This paper has presented a system, composed of an autonomous mobile robot, a 3D laser scanner, and scan matching algorithms for measuring and reconstructing of environments. Basic scan matching algorithms based on the ICP algorithm have been accelerated and extended to consistent multiview scan registration. A sophisticated reduction of scan points enables to maintain soft real time constraints in 3D scan matching. Multiview registration (simultaneous matching) based on the mutually alignment of a 3D scan with its neighbors generate overall consistent scenes.
Several applications, namely, the 3D reconstruction and modeling, deviation and deformation detection and 3D obstacle detection, have been presented. The algorithms have been tested in two different environments, i.e., in indoor, office environments and sewerage pipes. Further applications, e.g., crack detection in sewer pipes have to be tested. An additional advantage of the proposed systems is that the AIS 3D laser range finder measures actively distances and reflections. Vision-based approaches for sewerage pipes need additional power consuming light sources.
Future work will concentrate on more experiments in sewerage pipes and on sensor fusion with camera images for office environments.