Range Image Technique for Change Analysis of Rock Slopes Using Dense Point Cloud Data

Abstract

The use of a terrestrial laser scanner is examined to measure the changes of rock slopes subject to a wave attack test. Real scenarios are simulated in a water flume facility using a wave attack experiment representing a storm of 3000 waves. The stability of two rock slopes of different steepness was evaluated under the set conditions. For quantification of the changes of the slopes after the wave attack test, terrestrial laser scanning was used to acquire dense 3D point cloud data sampling for slope geometries before and after the wave attack experiment. After registration of the two scans, representing situations before and after the wave attack, the cloud-to-cloud distance was determined to identify areas in the slopes that were affected. Then, a range image technique was introduced to generate a raster image to facilitate a change analysis. Using these raster images, volume change was estimated as well. The results indicate that the area around the artificial coast line is most strongly affected by wave attacks. Another interesting phenomenon considers the change in transport direction of the rocks between the two slopes: from seaward transport for the steeper slope to landward transport for the milder slope. Using the range image technique, the work in this article shows that terrestrial laser scanning is an effective and feasible method for change analysis of long and narrow rock slopes.

TLS Measurement during Static Load Testing of a Railway Bridge

“…Surface models of point clouds are an adequate solution for surface objects such as cooling towers [40], dams [41][42], or tunnels [43]. The comparison of periodic surface models of an object in order to detect dislocation is a recognised procedure in landslide monitoring [44][45] and determining the progress of erosion of rocky cliffs [46][47][48]. The investigation into displacement and deformation of natural objects does not, however, require as great an accuracy as work with civil structures.…”

Suitability Study of Structure-from-Motion for the Digitisation of Architectural (Heritage) Spaces to Apply Divergent Photograph Collection

“…On the one hand, there are research works into the calibration of laser scanners to ascertain their measurement uncertainties, errors and accuracies [17][18][19][20][21][22][23]. It is also worth mentioning other applications of TLS technology, which include change detection and deformation monitoring in buildings, constructions and engineering systems [24][25][26][27][28][29], as well as the digitisation of archaeological heritage sites for analysis [7,30,31].…”

As-Built 3D Heritage City Modelling to Support Numerical Structural Analysis: Application to the Assessment of an Archaeological Remain

“…Barracani et al [12], due to the complexity of the Modena Cathedral, on the basis of static structural health monitoring (SHM) system and TLS in different stages, develop FEM models to investigate the different factors that have an effect on the structural behaviour. Shen et al [13] use TLS to capture dense point cloud data to quantify the changes of rock slopes due to water erosion, by carrying out cloud-to-cloud distance calculation and with a range image technique. Xu et al [14] monitor the deformations of an earth-rock dam in China during different periods by integrating TLS and non-uniform rational B-splines (NURBS) to create the 3D models to be compared.…”