A Model-based, Optimal Design System for Terrestrial Laser Scanning Networks in Complex Sites
Date
2019-08-29
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Abstract
With the rapid increase of terrestrial laser scanner (TLS) applications, especially for the high-accuracy modelling of large-volume, complex objects, a design system is required to provide the optimal solutions for both scanner and target placement, so that the project requirements in terms of coverage, precision, economy and reliability can be met. In this thesis, a model-based, optimal design system for terrestrial laser scanning networks in complex sites is proposed. First, a hierarchical TLS viewpoint planning strategy driven by an improved optimization method is developed to solve the optimal scanner placement problem. The main contribution of the proposed method is to improve the efficiency in design without jeopardizing the optimality of the solution, compared with the traditional method with the extensive search strategy. In addition, the target placement for registration, which draws limited attention in the existing research, is determined by optimizing the target arrangement criterion, and the number of target locations is minimized by accepting the close to optimal target arrangement. Finally, the quality of the design, including the sensitivity of the object coverage to viewpoint placement and the precision of the point cloud are provided. The proposed methods were verified by the relatively small network first and then applied on two building complexes located on the University of Calgary campus. The design for scanner placement was compared with the “brute force” strategy in terms of the optimality of the solutions and runtime. The results showed that the proposed strategy provided scanning networks with a compatible quality but a significantly improved efficiency in design. The number of target locations necessary for registration from the proposed system was surprisingly small, considering the volume and complexity of the networks. Through the quality assessments, the sensitivity of the object coverage to the scanner placement indicated where users might need to consider viewpoint densification, and the point cloud precision indicated if the network design could meet the project requirements.
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Keywords
Terrestrial Laser Scanning, Network Design, View planning, 3D Modelling, Point Cloud
Citation
Jia, F. (2019). A Model-based, Optimal Design System for Terrestrial Laser Scanning Networks in Complex Sites (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.