An Efficient, Hierarchical Viewpoint Planning Strategy for Terrestrial Laser Scanner Networks

Abstract

Terrestrial laser scanner (TLS) techniques have been widely adopted in a variety of applications. However, unlike in geodesy or photogrammetry, insufficient attention has been paid to the optimal TLS network design. It is valuable to develop a complete design system that can automatically provide an optimal plan, especially for high-accuracy, large-volume scanning networks. To achieve this goal, one should look at the “optimality” of the solution as well as the computational complexity in reaching it. In this paper, a hierarchical TLS viewpoint planning strategy is developed to solve the optimal scanner placement problems. If one targeted object to be scanned is simplified as discretized wall segments, any possible viewpoint can be evaluated by a score table representing its visible segments under certain scanning geometry constraints. Thus, the design goal is to find a minimum number of viewpoints that achieves complete coverage of all wall segments. The efficiency is improved by densifying viewpoints hierarchically, instead of a “brute force” search within the entire workspace. The experiment environments in this paper were simulated from two buildings located on University of Calgary campus. Compared with the “brute force” strategy in terms of the quality of the solutions and the runtime, it is shown that the proposed strategy can provide a scanning network with a compatible quality but with more than a 70 % time saving.

A Model-Based Design System for Terrestrial Laser Scanning Networks in Complex Sites

“…This category falls more under scope of TLS viewpoint planning research. Relevant papers include [21,29,[41][42][43][44][45]. A prior model is obtained from an existing 2D floor map or a quick 3D scan of the site.…”

“…Also, we propose a planning method for the target placement. The earlier contribution in [43] is briefly reviewed in Section 3 for completeness of our methodology. In this paper, the previous method has been modified to handle more detailed environments with internal/external obstacles and restricted areas, and it is tested on experiment environments with larger volume.…”

Complete Scene Reconstruction by Merging Images and Laser Scans

“…In addition, in order to completely cover the scene with as few laser scans as possible, several methods are proposed dealing with the issue of optimal terrestrial laser scanner network design [30], [31], [32], [33]. These methods are based on existing 2D building map [30], [32], [33] or 3D object model [31]. When performing optimization, several factors are considered.…”

From BIM to Scan Planning and Optimization for Construction Control

“…A similar solution is proposed by Soudarissanane et al [16], but in this case, the navigable space is gridded to generate the candidate positions and the visibility analysis of all positions can be time-consuming when dealing with large facilities. Jia et al [20] propose a more efficient approach to candidate generation. A coarse grid is used for obtain a first set of positions, their suitability for acquisition is evaluated for a proposed Weighted Greedy Algorithm (WGA).…”