Roughness determination of coarse grained alpine river bed surfaces using Terrestrial Laser Scanning data

2014 ◽  
Vol 58 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Henning Baewert ◽  
Martin Bimböse ◽  
Alexander Bryk ◽  
Eric Rascher ◽  
Karl-Heinz Schmidt ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Coarse Grained ◽  
River Bed ◽  
Alpine River

scholarly journals TLS and SfM Approach for Bulk Density Determination of Excavated Heterogeneous Raw Materials

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 174 ◽  
Author(s):  
Peter Blistan ◽  
Stanislav Jacko ◽  
Ľudovít Kovanič ◽  
Julián Kondela ◽  
Katarína Pukanská ◽  
...  
Keyword(s):  
Bulk Density ◽  
Laser Scanning ◽  
Large Scale ◽  
Raw Materials ◽  
Terrestrial Laser Scanning ◽  
Mineral Resources ◽  
Point Clouds ◽  
Raw Material

A frequently recurring problem in the extraction of mineral resources (especially heterogeneous mineral resources) is the rapid operative determination of the extracted quantity of raw material in a surface quarry. This paper deals with testing and analyzing the possibility of using unconventional methods such as digital close-range photogrammetry and terrestrial laser scanning in the process of determining the bulk density of raw material under in situ conditions. A model example of a heterogeneous deposit is the perlite deposit Lehôtka pod Brehmi (Slovakia). Classical laboratory methods for determining bulk density were used to verify the results of the in situ method of bulk density determination. Two large-scale samples (probes) with an approximate volume of 7 m3 and 9 m3 were realized in situ. 6 point samples (LITH) were taken for laboratory determination. By terrestrial laser scanning (TLS) measurement from 2 scanning stations, point clouds with approximately 163,000/143,000 points were obtained for each probe. For Structure-from-Motion (SfM) photogrammetry, 49/55 images were acquired for both probes, with final point clouds containing approximately 155,000/141,000 points. Subsequently, the bulk densities of the bulk samples were determined by the calculation from in situ measurements by TLS and SfM photogrammetry. Comparison of results of the field in situ measurements (1841 kg∙m−3) and laboratory measurements (1756 kg∙m−3) showed only a 4.5% difference in results between the two methods for determining the density of heterogeneous raw materials, confirming the accuracy of the used in situ methods. For the determination of the loosening coefficient, the material from both large-scale samples was transferred on a horizontal surface. Their volumes were determined by TLS. The loosening coefficient for the raw material of 1.38 was calculated from the resulting values.

scholarly journals Intelligent crack extraction based on terrestrial laser scanning measurement

2020 ◽  
Vol 53 (3-4) ◽  
pp. 416-426 ◽  
Author(s):  
Hao Yang ◽  
Xiangyang Xu
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Point Cloud Data ◽  
Time Cost ◽  
Visual Examination ◽  
Average Width ◽  
Cloud Data ◽  
Novel Method

The hazards of cracks, which could badly decrease reliability and safety of structures, are receiving increasing attention with the popularity of tunnel constructions. Traditional crack inspection relies on visual examination, which is time-, cost- and labor-intensive. Therefore, how to identify and measure cracks intelligently is significantly essential. The paper focuses on the Canny method to extract cracks of tunnel structures by the intensity value of reflectivity. We propose and investigate a novel method which combines dilation and the Canny algorithm to identify and extract the cracks automatically and intelligently based on the point cloud data of terrestrial laser scanning measurement. In order for measurement of cracks, the projection of summed edge pixels is adopted, where a synthesis is carried out on the detection results with all sampling parameters. Based on the synthesized image, vertical crack presents two sharp peaks where the space of the peaks indicates the average width of the crack, as well as its position. The advantage of the method is that it does not require determination of Canny detector parameters. The deviation between manual measurement and Canny detection is 2.92%.

scholarly journals Determination of Elevator Shaft Uprightness Applying the Terrestrial Laser Scanning Method / Určovanie Zvislosti Výťahovej Šachty Metódou Terestrického Laserového Skenovania

2013 ◽  
Vol 59 (3) ◽  
pp. 6-20
Author(s):  
Ľudovít Kovanič
Keyword(s):  
Spatial Data ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Measured Data ◽  
Geometrical Parameters ◽  
Scanning Method ◽  
Precise Method ◽  
Geodetic Measurements

Abstract This paper presents the results obtained from geodetic measurements and processing the data with the objective to determine geometrical parameters of an elevator shaft applying classical as well as modern approaches for obtaining the measured data. The intention was to verify the possibility to apply the terrestrial laser scanning (TLS) method as a suitable, efficient and precise method for collecting spatial data.

scholarly journals INDIVIDUAL ROCKS SEGMENTATION IN TERRESTRIAL LASER SCANNING POINT CLOUD USING ITERATIVE DBSCAN ALGORITHM

2018 ◽  
Vol XLII-2 ◽  
pp. 1157-1161
Author(s):  
A. Walicka ◽  
G. Jóźków ◽  
A. Borkowski
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Automatic Segmentation ◽  
Terrestrial Laser Scanning ◽  
Principal Component ◽  
Test Sample ◽  
Dbscan Algorithm ◽  
Fluvial Transport ◽  
River Bed ◽  
Movement Parameters

The fluvial transport is an important aspect of hydrological and geomorphologic studies. The knowledge about the movement parameters of different-size fractions is essential in many applications, such as the exploration of the watercourse changes, the calculation of the river bed parameters or the investigation of the frequency and the nature of the weather events. Traditional techniques used for the fluvial transport investigations do not provide any information about the long-term horizontal movement of the rocks. This information can be gained by means of terrestrial laser scanning (TLS). However, this is a complex issue consisting of several stages of data processing. In this study the methodology for individual rocks segmentation from TLS point cloud has been proposed, which is the first step for the semi-automatic algorithm for movement detection of individual rocks. The proposed algorithm is executed in two steps. Firstly, the point cloud is classified as rocks or background using only geometrical information. Secondly, the DBSCAN algorithm is executed iteratively on points classified as rocks until only one stone is detected in each segment. The number of rocks in each segment is determined using principal component analysis (PCA) and simple derivative method for peak detection. As a result, several segments that correspond to individual rocks are formed. Numerical tests were executed on two test samples. The results of the semi-automatic segmentation were compared to results acquired by manual segmentation. The proposed methodology enabled to successfully segment 76 % and 72 % of rocks in the test sample 1 and test sample 2, respectively.

scholarly journals Determination of Terrain Profile from TLS Data by Applying Msplit Estimation

2020 ◽  
Vol 13 (1) ◽  
pp. 31
Author(s):  
Patrycja Wyszkowska ◽  
Robert Duchnowski ◽  
Andrzej Dumalski
Keyword(s):  
Data Processing ◽  
Least Squares ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Vertical Displacement ◽  
Least Squares Estimation ◽  
Displacement Analysis ◽  
Empirical Tests ◽  
The Absolute

This paper presents an application of an Msplit estimation in the determination of terrain profiles from terrestrial laser scanning (TLS) data. We consider the squared Msplit estimation as well as the absolute Msplit estimation. Both variants have never been used to determine terrain profiles from TLS data (the absolute Msplit estimation has never been applied in any TLS data processing). The profiles are computed by applying polynomials of a different degree, determining which coefficients are estimated using the method in question. For comparison purposes, the profiles are also determined by applying a conventional least squares estimation. The analyses are based on simulated as well as real TLS data. The actual objects have been chosen to contain terrain details (or obstacles), which provide some measurements which are not referred to as terrain surface; here, they are regarded as outliers. The empirical tests prove that the proposed approach is efficient and can provide good terrain profiles even if there are outliers in an observation set. The best results are obtained when the absolute Msplit estimation is applied. One can suggest that this method can be used in a vertical displacement analysis in mining damages or ground disasters.

scholarly journals MONITORING OF FLUVIAL TRANSPORT IN THE MOUNTAIN RIVER BED USING TERRESTRIAL LASER SCANNING

2016 ◽  
Vol XLI-B7 ◽  
pp. 523-528
Author(s):  
G. Jozkow ◽  
A. Borkowski ◽  
M. Kasprzak
Keyword(s):  
Laser Scanning ◽  
River Flow ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
Major Axis ◽  
Strong Impact ◽  
Mountain River ◽  
Mountain Areas ◽  
Fluvial Transport ◽  
River Bed

The fluvial transport is the surface process that has a strong impact on the topography changes, especially in mountain areas. Traditional hydrological measurements usually give a good understanding of the river flow, however, the information of the bedload movement in the rivers is still insufficient. In particular, there is limited knowledge about the movement of the largest clasts, i.e. boulders. This investigation addresses mentioned issues by employing Terrestrial Laser Scanning (TLS) to monitor annual changes of the mountain river bed. The vertical changes were estimated based on the Digital Elevation Model (DEM) of difference (DoD) while transported boulders were identified based on the distances between point clouds and RGB-coloured points. Combined RGB point clouds allowed also to measure 3D displacements of boulders. The results showed that the highest dynamic of the fluvial process occurred between years 2012-2013. Obtained DoD clearly indicated alternating zones of erosion and deposition of the sediment finer fractions in the local sedimentary traps. The horizontal displacement of the rock material in the river bed showed high complexity resulting in the displacement of large boulders (major axis about 0.8 m) for the distance up to 2.3 m.

scholarly journals OPTIMISATION OF THE CALIBRATION PROCESS OF A K-TLS BASED MULTI-SENSOR-SYSTEM BY GENETIC ALGORITHMS

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 1655-1662
Author(s):  
J. Hartmann ◽  
I. von Gösseln ◽  
N. Schild ◽  
A. Dorndorf ◽  
J.-A. Paffenholz ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Uncertainty Propagation ◽  
Terrestrial Laser Scanning ◽  
Qualitative Assessment ◽  
Optimal Arrangement ◽  
System Calibration ◽  
3D Object ◽  
The One ◽  
3D Object Detection

<p><strong>Abstract.</strong> In recent years, the requirements in the industrial production of elongated objects, e.g., aircraft, have been increased. An essential aspect of the production process is the 3D object detection as well as the qualitative assessment of the captured data. On the one hand high accuracy requirements with a 3D standard deviation of &amp;sigma;<sub>3D</sub>&amp;thinsp;=&amp;thinsp;1&amp;thinsp;mm have to be fulfilled, on the other hand an efficient 3D object capturing is needed. In terms of efficiency, kinematic terrestrial laser scanning (k-TLS) has proven its strength in the recent years. It can be seen as an alternative and is even more powerful than to the well established static terrestrial laser scanning (s-TLS). In order to perform a high accurate 3D object capturing with k-TLS, the 3D object capturing of the initial sensor, the (geo-)referencing of the mobile platform, the synchronisation of all sensors and the system calibration, which means the determination of six extrinsic parameters have to be performed with suitable accuracy. Within this contribution we focus on the system calibration. Therefore an approach based on known reference geometries, here planes, is used (Strübing and Neumann, 2013). As a result, the lever arm and boresight angles are determined. Hereby the number as well as the position and orientation of the reference geometries is of importance. Therefore, an optimal arrangement has to be found. Here a sensitive analysis based on uncertainty propagation is used. A selective search of an optimised arrangement is carried out by a genetic algorithm. Within some examples we demonstrate some theoretical aspects and how an optimisation of the reference geometry arrangement can be achieved.</p>

scholarly journals MONITORING OF FLUVIAL TRANSPORT IN THE MOUNTAIN RIVER BED USING TERRESTRIAL LASER SCANNING

2016 ◽  
Vol XLI-B7 ◽  
pp. 523-528 ◽  
Author(s):  
G. Jozkow ◽  
A. Borkowski ◽  
M. Kasprzak
Keyword(s):  
Laser Scanning ◽  
River Flow ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
Major Axis ◽  
Strong Impact ◽  
Mountain River ◽  
Mountain Areas ◽  
Fluvial Transport ◽  
River Bed

The fluvial transport is the surface process that has a strong impact on the topography changes, especially in mountain areas. Traditional hydrological measurements usually give a good understanding of the river flow, however, the information of the bedload movement in the rivers is still insufficient. In particular, there is limited knowledge about the movement of the largest clasts, i.e. boulders. This investigation addresses mentioned issues by employing Terrestrial Laser Scanning (TLS) to monitor annual changes of the mountain river bed. The vertical changes were estimated based on the Digital Elevation Model (DEM) of difference (DoD) while transported boulders were identified based on the distances between point clouds and RGB-coloured points. Combined RGB point clouds allowed also to measure 3D displacements of boulders. The results showed that the highest dynamic of the fluvial process occurred between years 2012-2013. Obtained DoD clearly indicated alternating zones of erosion and deposition of the sediment finer fractions in the local sedimentary traps. The horizontal displacement of the rock material in the river bed showed high complexity resulting in the displacement of large boulders (major axis about 0.8&thinsp;m) for the distance up to 2.3&thinsp;m.

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