Optimal scan planning with enforced network connectivity for the acquisition of three-dimensional indoor models

The positioning of laser scanners for indoor surveying is still a time and cost expensive process. This article proposes an optimization approach for computing an admissible sensor placement with the minimal number of sensor view point positions. The approach facilitates both wall and floor surveying based on a floorplan of the study object. Optimal solutions are calculated by solving an Integer Linear Program that respects manufacturer specifications incorporating constraints such as full coverage. To enable a subsequent coregistration of the scans, a flow-based constraint formulation ensuring the connectivity of the selected positions in an appropriately defined geometric intersection graph is introduced. The method has been evaluated on real-world objects and compared to heuristic methods that have frequently been used for related problems. Our solutions outperform heuristic approaches regarding both running time and the number of TLS stations. In a case study with a larger floorplan of an institute building and with different parameter settings, our method resulted in a solution with at least two stations less compared to a solution generated by an expert.