Viewshed simulation and optimization for digital terrain modelling with terrestrial laser scanning

Abstract

The main objective of this study is the development of a simulation and optimization method for wide-area terrain mapping with terrestrial laser scanning (TLS). The problem can be stated as follows: given a prior digital surface model (DSM) of a region of interest (e.g. from airborne lidar or structure-from-motion photogrammetry), determine the minimum number of scan locations required to seamlessly scan the terrain in the region for a given scanner range and angular field-ofview (FOV). An optimization method for measurement setup is developed using multiple viewshed analysis and simulated annealing (SA) constrained by the system performance characteristics and survey specifications. The method is evaluated at a sediment and erosion control facility with hilly terrain by comparing random scan locations versus optimized three to six scan locations. Statistical results illustrate that average visibility for random sampling increases gradually with scan locations. However, random sampling clearly underperforms in terms of scan visibility relative to five or six optimized scan locations with an average visibility of 100%. Similar patterns in optimized scan locations demonstrate that certain terrain morphometry at the study site is an essential factor for TLS survey design. Finally, an optimized solution is compared to a brute-force manual solution for determining four scan locations for conducting surveys at the study site. Results show the effectiveness of the optimization method for selecting combinations of scan locations that enable more efficient TLS survey coverage over a wider terrain area compared to manual selection. Furthermore, results demonstrate the adaptability of the method to take into consideration different scan parameters and survey conditions, such as pre-determined scan locations that may be required (e.g. a survey control monument).

Combined Use of Aerial Photogrammetry and Terrestrial Laser Scanning for Detecting Geomorphological Changes in Hornsund, Svalbard

“…The DEM at interpolated areas has a quality lower than estimated in the study. In the future, viewshed analysis before TLS fieldwork could remove the shadowing effect [50,51] and improve the accuracy of the data.…”

Towards Managing Visual Pollution: A 3D Isovist and Voxel Approach to Advertisement Billboard Visual Impact Assessment

“…Moreover, it was also expected that 3D isovist computation time would not exceed 1 h. The above assumptions were tested on 200 × 200 and 40 m (length, width, height) voxel bounding box. The bounding box length and width dimensions correspond to the foreground visibility range recommendations proposed by Palmer [51] as well as other visibility simulation experiments [52], the height of the bounding box corresponds to the difference in height between the observer's point and the highest building of the case study. The experiment was set up using a single measurement point located in the center of the bottom of the bounding box and elevated 1.7 m above ground level to reflect the mean eye height of the pedestrian observer.…”

Method and Experiment for Quantifying Local Features of Hard Bottom Contours When Driving Intelligent Farm Machinery in Paddy Fields

“…Man Zhang et al constructed a 3D terrain information measurement system using real-time differential (RTD) and laser measurement technology [18], which provided a solution for topographic measurements. Starek et al used the kriging spatial interpolation method for wide-area terrain prediction and modeling based on a high-density, laser-scanned point cloud obtained over the total area of an experimental station [19]. Tuanpeng Tu et al combined GNSS and attitude and heading reference system (AHRS) technologies to achieve hard substrate contour acquisition and digital representations of paddy fields using an unmanned direct rice seeding machine chassis with an elevation standard error of less than 2 cm [20].…”