Accurate Measurement of the Riverbed Model for Deformation Analysis using Laser Scanning Technology

Abstract

<p>This paper presents an interesting application of the riverbed model shape and deformations monitoring using laser scanning technology and accurate local micro-network. The most interesting fact about this application is very high accuracy demand on deformation determination (maximum permissible error is only 2 mm) within quite large object (the size of the riverbed model is about 100 meters). Up to now, mechanical calipers in the selected profiles were used to detect the changes. This manual approach is very laborious and time-consuming and the gathered data resolution and accuracy is often not sufficient. The suggested solution contains two main parts. The first part deals with construction of highly accurate local micro-network for laser scanning needs (maximum required standard deviation in any coordinate is lower than 0.4 mm) and the second part deals with actual laser scanning and data processing. Design, measurement and processing of the experiment was conducted for the needs of the research project “Improvement of navigation conditions on the Elbe between Ústí nad Labem - state border CR / FRG - Navigation Step Děčín”. The main goal of this project is design and realization of the river regulation to improve the navigation conditions. The key benefit of using river model is the possibility to easily simulate various catastrophic scenarios (various degrees of the floods) and their impacts on riverbed changes.</p>

Influence of Material on the Density of a Point Cloud Created Using a Structured-Light 3D Scanner

“…Therefore, if light is not reflected at either the planar or non-planar interface, the sensor would have nothing to capture and evaluate. Therefore, transparent or translucent materials cannot be scanned without surface treatment [1]. The color of the scanned object is closely related to light scattering and the scanning itself.…”

“…Current research in the field of creating 3D models of real objects is moving in the direction of obtaining very high-density and voluminous point clouds, either by laser 3D scanning or structured-light 3D scanning [1]. Although these methods provide relatively high-density data in the form of point clouds, it is very time-and cost-intensive to process these data for the creation of digital models [2].…”

“…It is obvious that when the amount of data contained in a point cloud is limited, distortions and inaccuracies occur in the creation of a 3D model [10]. However, in many cases, the mere geometry of the shapes of the scanned object will be sufficient, and we will not need to acquire data about the surface texture of the material or its color [1,11]. It turns out, however, that when scanning processes are simplified, the density of the scanned point clouds will be directly influenced by the type of surface in question [12,13].…”

Use of TLS Technology in Highway Construction

“…According to the basic formulation of balancing problems, it is generally true that when repeated measurements of the same quantity are made, different results will be obtained, i.e., that individual measurements are influenced by many elements that cannot be completely eliminated, such as imperfections in our perceptual senses, instruments, climatic conditions, etc. By using a more accurate instrument, choosing the right conditions for measurement, and by experience, we can only reduce this influence and thus achieve the desired accuracy of the measurement (Štroner & Křemen, 2017).…”