scholarly journals A comparison of measurement methods: terrestrial laser scanning, tachymetry and snow probing for the determination of the spatial snow-depth distribution on slopes

2008 ◽  
Vol 49 ◽  
pp. 210-216 ◽  
Author(s):  
A. Prokop ◽  
M. Schirmer ◽  
M. Rub ◽  
M. Lehning ◽  
M. Stocker
Keyword(s):  
Snow Depth ◽  
Laser Scanning ◽  
Near Infrared ◽  
Depth Distribution ◽  
Terrestrial Laser Scanning ◽  
Weather Conditions ◽  
Measurement Methods ◽  
Measuring System ◽  
Protection Measures

AbstractDetermination of the spatial snow-depth distribution is important in potential avalanche-starting zones, both for avalanche prediction and for the dimensioning of permanent protection measures. Knowledge of the spatial distribution of snow is needed in order to validate snow depths computed from snowpack and snowdrift models. The inaccessibility of alpine terrain and the acute danger of avalanches complicate snow-depth measurements (e.g. when probes are used), so the possibility of measuring the snowpack using terrestrial laser scanning (TLS) was tested. The results obtained were compared to those of tachymetry and manual snow probing. Laser measurements were taken using the long-range laser profile measuring system Riegl LPM-i800HA. The wavelength used by the laser was 0.9 μm (near-infrared). The accuracy was typically within 30 mm. The highest point resolution was 30 mm when measured from a distance of 100 m. Tachymetry measurements were carried out using Leica TCRP1201 systems. Snowpack depths measured by the tachymeter were also used. The datasets captured by tachymetry were used as reference models to compare the three different methods (TLS, tachymetry and snow probing). This is the first time that the accuracy of TLS systems in snowy and alpine weather conditions has been quantified. The relative accuracy between the three measurement methods is bounded by a maximum offset of ±8 cm. Between TLS and the tachymeter the standard deviation is 1σ = 2 cm, and between manual probing and TLS it is up to 1σ = 10 cm, for maximum distances for the TLS and tachymeter of 300 m.

scholarly journals MAPPING SNOW DEPTH WITH AUTOMATED TERRESTRIAL LASER SCANNING – INVESTIGATING POTENTIAL APPLICATIONS

2017 ◽  
Vol XLII-4/W4 ◽  
pp. 537-540
Author(s):  
M. S. Adams ◽  
T. Gigele ◽  
R. Fromm
Keyword(s):  
Spatial Resolution ◽  
Glass Fibre ◽  
Snow Depth ◽  
Laser Scanning ◽  
Depth Distribution ◽  
Explanatory Power ◽  
Terrestrial Laser Scanning ◽  
Snow Drift ◽  
Potential Applications ◽  
Research Questions

This contribution presents an automated terrestrial laser scanning (ATLS) setup, which was used during the winter 2016/17 to monitor the snow depth distribution on a NW-facing slope at a high-alpine study site. We collected data at high temporal [(sub-)daily] and spatial resolution (decimetre-range) over 0.8 km² with a Riegl LPM-321, set in a weather-proof glass fibre enclosure. Two potential ATLS-applications are investigated here: monitoring medium-sized snow avalanche events, and tracking snow depth change caused by snow drift. The results show the ATLS data’s high explanatory power and versatility for different snow research questions.

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 Mapping the annual evolution of snow depth in a small catchment in the Pyrenees using the long-range terrestrial laser scanning

2014 ◽  
Vol 10 (3) ◽  
pp. 379-393 ◽  
Author(s):  
J. Revuelto ◽  
J.I. López-Moreno ◽  
C. Azorin-Molina ◽  
J. Zabalza ◽  
G. Arguedas ◽  
...  
Keyword(s):  
Long Range ◽  
Snow Depth ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Small Catchment

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 Identification of Problems Associated with the Usage of Friction (Koeppe) Hoists Based on Geodetic Measurements

Geosciences ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 444
Author(s):  
Agnieszka Ochałek ◽  
Wojciech Jaśkowski ◽  
Mateusz Jabłoński
Keyword(s):  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Indirect Costs ◽  
Measurement Methods ◽  
Legal Regulations ◽  
Direct And Indirect Costs ◽  
Cost Of Materials ◽  
The Cost ◽  
Assembly Component ◽  
Selection Of

The hoist assembly based on the Koeppe friction is a commonly used solution in mining. However, it has some disadvantages. A few centimeters offset of the groove axis can lead to excessive abrasion of linings on the Koeppe friction and pulleys. As a consequence, the mines are forced to bear the direct and indirect costs of replacing the linings such as the cost of materials and service as well as the cost of extended machine and shaft downtime. Last year, the authors undertook a geodetic inventory of the condition of two hoisting machines with a Koeppe winder. Terrestrial laser scanning enhanced with precision total station measurements were performed. Additionally, elements particularly important for the performed analysis (inclination of hoisting machine and rope wheels shafts) were determined by the precision leveling technique. Obtained results were verified using measurements on Szpetkowski’s tribrach. Appropriate selection of the measurement methods in both analyzed examples allowed us to determine the causes of destruction of each hoist assembly component. Based on precise geodetic data, guidelines have been defined for rectification (twisting and shifting the rope pulleys), which seems unavoidable despite the lack of unambiguous legal regulations.

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