Terrestrial laserscanning system Mensi GS100 : accuracy tests, experiences and projects at the Hamburg University of Applied Sciences

Abstract

3D terrestrial laser scanning is well on the way to proving itself to be a 3D measurement technique that can complement or replace the established techniques of photogrammetry and tacheometry. For this reason investigations into accuracies and behavior are very important for the understanding and improvement of such measuring systems. The Department of Geomatics at Hamburg University of Applied Sciences has investigated the terrestrial 3D laser scanning system Mensi GS100/GS200 regarding the accuracy of distances measured and practical handling of the equipment in projects. It can be stated that distances measured with the laser scanner Mensi GS100 are systematically too long when compared to reference distances and that distances measured to spheres and targets placed on identical points are systematically different. In registration and geo-referencing of point clouds using Mensispheres and targets in a 3D test field standard deviations of approx. 3mm could be achieved when compared to reference points. Investigations into the planarity of a stone slab showed measurement noise of some millimeters in the point cloud; which is within the range of the measuring accuracy. The laser scanners Mensi GS100 and GS200 have already been used in several projects at the HAW Hamburg and also in co-operation with a private engineering office. First experiences in data acquisition, registration and georeferencing will be reported in this paper using both systems.