Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13882
J. Zaczek-Peplinska, M. Kowalska, Krystian Ryczko, Cezary Sekular
Modern measurement technologies are widely used for the monitoring and determination of surface deformations. One more frequently used measurement technology is terrestrial laser scanning (TLS), which provides quasi-continuous information about the tested surface in the form of a point cloud at a given resolution. At the same time, TLS is based on measuring the distance in a given direction, thanks to which we can obtain a high precision of measurement, often compared to tacheometric measurements. This paper presents a study on the determination of surface flatness parameters extracted from a point cloud. It takes into account the roughness characteristics of the different structures on the measured surfaces and analyzes them using the most popular algorithms for determining the distance of points from the reference surface. Additionally, the review presents the issue of expanding selected surfaces onto a plane to analyze their geometric parameters, and thus to determine the deformation. The applied solution can be used to monitor the deformation of objects such as tunnels and interiors of collectors or large-diameter downpipes, the shape of which is similar to a cylinder surface. Thanks to the expansion of the cylinder surface into a plane, it is possible to perform a comprehensive analysis of surface deformation, and not only selected fragments in the form of sections. The conducted analyses show the great potential of data obtained using terrestrial laser scanning, when an appropriate procedure and data processing method are applied. This paper focuses on two types of studies; the study of surface flatness and analysis of the deformation of cylindrical surfaces. These types of studies are extremely useful in assessing the technical condition of structures, especially in studying the deformation of structures built underground (tunnels, passages, warehouses), where the loads from the surrounding earth are significant.
{"title":"Selected aspects of geometrical analyses of surfaces measured using terrestrial laser scanning (TLS)","authors":"J. Zaczek-Peplinska, M. Kowalska, Krystian Ryczko, Cezary Sekular","doi":"10.4995/jisdm2022.2022.13882","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13882","url":null,"abstract":"Modern measurement technologies are widely used for the monitoring and determination of surface deformations. One more frequently used measurement technology is terrestrial laser scanning (TLS), which provides quasi-continuous information about the tested surface in the form of a point cloud at a given resolution. At the same time, TLS is based on measuring the distance in a given direction, thanks to which we can obtain a high precision of measurement, often compared to tacheometric measurements. This paper presents a study on the determination of surface flatness parameters extracted from a point cloud. It takes into account the roughness characteristics of the different structures on the measured surfaces and analyzes them using the most popular algorithms for determining the distance of points from the reference surface. Additionally, the review presents the issue of expanding selected surfaces onto a plane to analyze their geometric parameters, and thus to determine the deformation. The applied solution can be used to monitor the deformation of objects such as tunnels and interiors of collectors or large-diameter downpipes, the shape of which is similar to a cylinder surface. Thanks to the expansion of the cylinder surface into a plane, it is possible to perform a comprehensive analysis of surface deformation, and not only selected fragments in the form of sections. The conducted analyses show the great potential of data obtained using terrestrial laser scanning, when an appropriate procedure and data processing method are applied. This paper focuses on two types of studies; the study of surface flatness and analysis of the deformation of cylindrical surfaces. These types of studies are extremely useful in assessing the technical condition of structures, especially in studying the deformation of structures built underground (tunnels, passages, warehouses), where the loads from the surrounding earth are significant.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126159804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13893
R. Shults
The concept of analysis of geodetic monitoring results solely from a geometric point of view is recognized as an obsolete approach. A complex analysis of geodetic measurements (geometric approach) and the structure stress-strain analysis (mechanical approach) allows obtaining the whole picture of any engineering structure displacements. The detailed scheme of the structural analysis of geospatial monitoring results of the long-span roof structures has been given in the presented paper. The results of the geospatial monitoring of the large warehouse have been chosen as a study subject. The structure's roof consists of planar trusses, the main objects of external loads combined with dead loads. According to the complex analysis procedure, the trusses were analyzed using the method of joints with the determination of partial member forces. At the next step, these forces were leveraged in the following order member force–member deformation–node displacement. To obtain the actual displacements of the truss nodes, one has to account for the vertical displacements of the leaning points where the truss touched the column. That step is also being accomplished using the method of joints. Having the actual node displacements, one may compare them with geodetic monitoring results. The comparison results generally allow us to reveal the places with unacceptable displacements and estimate whether they are determined with the necessary accuracy. In this particular case, the final node's displacements were yielded as an output of combined analysis, both geometric and mechanical. That, in turn, lets to acquire the deformation process's genuine parameters. The study results have shown the high efficiency of the presented research methodology.
{"title":"Structural analysis of monitoring results of long-span roof structures","authors":"R. Shults","doi":"10.4995/jisdm2022.2022.13893","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13893","url":null,"abstract":"The concept of analysis of geodetic monitoring results solely from a geometric point of view is recognized as an obsolete approach. A complex analysis of geodetic measurements (geometric approach) and the structure stress-strain analysis (mechanical approach) allows obtaining the whole picture of any engineering structure displacements. The detailed scheme of the structural analysis of geospatial monitoring results of the long-span roof structures has been given in the presented paper. The results of the geospatial monitoring of the large warehouse have been chosen as a study subject. The structure's roof consists of planar trusses, the main objects of external loads combined with dead loads. According to the complex analysis procedure, the trusses were analyzed using the method of joints with the determination of partial member forces. At the next step, these forces were leveraged in the following order member force–member deformation–node displacement. To obtain the actual displacements of the truss nodes, one has to account for the vertical displacements of the leaning points where the truss touched the column. That step is also being accomplished using the method of joints. Having the actual node displacements, one may compare them with geodetic monitoring results. The comparison results generally allow us to reveal the places with unacceptable displacements and estimate whether they are determined with the necessary accuracy. In this particular case, the final node's displacements were yielded as an output of combined analysis, both geometric and mechanical. That, in turn, lets to acquire the deformation process's genuine parameters. The study results have shown the high efficiency of the presented research methodology.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124186639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13786
J. Guillory, D. Truong, J. Wallerand
We present our first results in the realization of an absolute distance meter that will bring well-defined and metrologically traceable measurements for distances of several kilometers. The purpose is to achieve an accuracy of 1 mm up to 5 km and beyond. To this end, the developed prototype operates at two different wavelengths, 780 nm and 1560 nm. For each of these wavelengths, the measured distance is determined from the phase accumulated by a radio-frequency carrier propagated in air by a laser beam modulated in intensity. Thus, using the dispersion relation between these two measurements, a compensation of the refractive index of air can be applied, i.e. no measurement of temperature, pressure and CO2 content of the air is required. In this paper, the principle of the two-wavelength absolute distance meter is explained, and preliminary results are presented, for each wavelength and with air refractive index compensation.
{"title":"Optical distance measurements at two wavelengths with air refractive index compensation","authors":"J. Guillory, D. Truong, J. Wallerand","doi":"10.4995/jisdm2022.2022.13786","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13786","url":null,"abstract":"We present our first results in the realization of an absolute distance meter that will bring well-defined and metrologically traceable measurements for distances of several kilometers. The purpose is to achieve an accuracy of 1 mm up to 5 km and beyond. To this end, the developed prototype operates at two different wavelengths, 780 nm and 1560 nm. For each of these wavelengths, the measured distance is determined from the phase accumulated by a radio-frequency carrier propagated in air by a laser beam modulated in intensity. Thus, using the dispersion relation between these two measurements, a compensation of the refractive index of air can be applied, i.e. no measurement of temperature, pressure and CO2 content of the air is required. In this paper, the principle of the two-wavelength absolute distance meter is explained, and preliminary results are presented, for each wavelength and with air refractive index compensation.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123250489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13933
J. L. Lerma, M. Cabrelles, L. García-Asenjo, P. Garrigues, Laura Martínez
The paper describes the processing and validation of a series of terrestrial photogrammetric surveys carried out from 2017 to 2020 for monitoring the stability of a cliff in Cortes de Pallás (Spain). The complexity of the target area, which has a strong orography, a water reservoir, and many obstacles such as electrical power lines or vegetation, makes difficult the use of any measurement technique. After considering solutions such as long-range laser scanning or close-range mobile mapping, which were unsatisfactorily tested and therefore rejected for future campaigns, the use of combined short and long terrestrial photogrammetry proved an efficient method for quick and massive monitoring of the entire cliff with an overall accuracy of several centimetres. All the steps undertaken for the centimetre level accuracy deliverables, which include camera calibration, bundle-adjustment, dense point cloud generation, 3D modelling, and validation of the 3D models by using external geodetic information, will be presented. For the sake of conciseness, only results for the last two campaigns (5th and 6th), as well as the comparison between the last (6th) and the first (1st) campaigns, will be discussed. In addition, photogrammetric results will be validated by analyzing the metrics on four target-based micro-geodetic check points, located on key critical areas of the cliff selected by civil and geotechnical engineers from the Department of Roads and Infrastructures.
本文描述了2017年至2020年为监测西班牙Cortes de Pallás悬崖稳定性而进行的一系列陆地摄影测量调查的处理和验证。目标地区地形复杂，有水库，还有许多障碍物，如电线或植被，这使得使用任何测量技术都很困难。在考虑了远程激光扫描或近距离移动测绘等解决方案之后，这些解决方案经过了不满意的测试，因此在未来的活动中被拒绝，使用短长陆地摄影测量相结合的方法被证明是一种有效的方法，可以快速和大规模地监测整个悬崖，总体精度达到几厘米。将介绍厘米级精度交付的所有步骤，包括相机校准，捆绑调整，密集点云生成，3D建模以及使用外部大地测量信息验证3D模型。为了简洁起见，我们将只讨论最后两个战役(第5和第6)的结果，以及最后两个战役(第6)和第一个战役(第1)的比较。此外，摄影测量结果将通过分析四个基于目标的微大地测量检查点的度量来验证，这些检查点位于悬崖的关键区域，由道路和基础设施部的土木和岩土工程师选择。
{"title":"Long and close-range terrestrial photogrammetry for rocky landscape deformation monitoring","authors":"J. L. Lerma, M. Cabrelles, L. García-Asenjo, P. Garrigues, Laura Martínez","doi":"10.4995/jisdm2022.2022.13933","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13933","url":null,"abstract":"The paper describes the processing and validation of a series of terrestrial photogrammetric surveys carried out from 2017 to 2020 for monitoring the stability of a cliff in Cortes de Pallás (Spain). The complexity of the target area, which has a strong orography, a water reservoir, and many obstacles such as electrical power lines or vegetation, makes difficult the use of any measurement technique. After considering solutions such as long-range laser scanning or close-range mobile mapping, which were unsatisfactorily tested and therefore rejected for future campaigns, the use of combined short and long terrestrial photogrammetry proved an efficient method for quick and massive monitoring of the entire cliff with an overall accuracy of several centimetres. All the steps undertaken for the centimetre level accuracy deliverables, which include camera calibration, bundle-adjustment, dense point cloud generation, 3D modelling, and validation of the 3D models by using external geodetic information, will be presented. For the sake of conciseness, only results for the last two campaigns (5th and 6th), as well as the comparison between the last (6th) and the first (1st) campaigns, will be discussed. In addition, photogrammetric results will be validated by analyzing the metrics on four target-based micro-geodetic check points, located on key critical areas of the cliff selected by civil and geotechnical engineers from the Department of Roads and Infrastructures.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115823987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13847
H. Nikolov, M. Atanasova
In this paper we used synthetic aperture radar (SAR) data to investigate the surface displacements in the area of archaeological site Solnitsata dated VI-V millennium BC. The researched zone is situated in the neighborhood of the Provadia town, NE Bulgaria found and is considered to be one of the most ancient in Europe. Close to it the industrial Mirovo salt deposit is located. From decadal observations it was established that in the area of both sites there are ground motions due to local tectonic movements (several faults are closely located) and active exploitation of the orebody. To study the geodynamic processes in this zone for the period 2015 – 2020 the Differential Interferometry Synthetic Aperture Radar (DInSAR) method was used for their registration. The results presented are from processing SAR data from ESA’s Sentinel-1 mission and coincide with the results obtained by geodetic measurements. Definite advantage of the used technique is the possibility to deliver information for much larger areas than the one provided by geodetic measurements. Other plus of the method is the availability of results regardless of the weather conditions.
{"title":"Registering the ground deformations at the area of the archaeological site “Solnitsata”","authors":"H. Nikolov, M. Atanasova","doi":"10.4995/jisdm2022.2022.13847","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13847","url":null,"abstract":"In this paper we used synthetic aperture radar (SAR) data to investigate the surface displacements in the area of archaeological site Solnitsata dated VI-V millennium BC. The researched zone is situated in the neighborhood of the Provadia town, NE Bulgaria found and is considered to be one of the most ancient in Europe. Close to it the industrial Mirovo salt deposit is located. From decadal observations it was established that in the area of both sites there are ground motions due to local tectonic movements (several faults are closely located) and active exploitation of the orebody. To study the geodynamic processes in this zone for the period 2015 – 2020 the Differential Interferometry Synthetic Aperture Radar (DInSAR) method was used for their registration. The results presented are from processing SAR data from ESA’s Sentinel-1 mission and coincide with the results obtained by geodetic measurements. Definite advantage of the used technique is the possibility to deliver information for much larger areas than the one provided by geodetic measurements. Other plus of the method is the availability of results regardless of the weather conditions.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132058234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13876
M. Crosetto, L. Solari, M. Mróz
This paper describes the first results of the European Ground Motion Service (EGMS). The EGMS is part of the Copernicus Land Monitoring Service and represents a unique initiative for performing ground deformation monitoring at a European scale. This service makes use of Advanced Differential Interferometric SAR (A-DInSAR) techniques based on satellite Synthetic Aperture Radar (SAR) imagery. In particular, it exploits the Sentinel-1A/B SAR images of the Copernicus Programme, acquired over Europe. The paper briefly summarizes the main characteristics of the EGMS, describing different products of this Service. Then it presents some case studies extracted from the EGMS products. Examples of natural and human-induced geohazards are described.
{"title":"Pan-European deformation monitoring: The European Ground Motion Service","authors":"M. Crosetto, L. Solari, M. Mróz","doi":"10.4995/jisdm2022.2022.13876","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13876","url":null,"abstract":"This paper describes the first results of the European Ground Motion Service (EGMS). The EGMS is part of the Copernicus Land Monitoring Service and represents a unique initiative for performing ground deformation monitoring at a European scale. This service makes use of Advanced Differential Interferometric SAR (A-DInSAR) techniques based on satellite Synthetic Aperture Radar (SAR) imagery. In particular, it exploits the Sentinel-1A/B SAR images of the Copernicus Programme, acquired over Europe. The paper briefly summarizes the main characteristics of the EGMS, describing different products of this Service. Then it presents some case studies extracted from the EGMS products. Examples of natural and human-induced geohazards are described.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125028182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13632
J. Arnoso, U. Riccardi, U. Tammaro, M. Benavent, F. G. Montesinos, E. Vélez
We present a study of the deformation pattern in El Hierro Island through the analysis of GNSS data from surveys carried out between 2015 and 2019 as well as continuous data. The last eruption in El Hierro occurred under the sea on the south rift, lasted from October 2011 to March 2012, and it was preceded by intense seismic activity and nearly 5 cm ground inflation. After this eruptive cycle, further magmatic intrusions were detected, from June 2012 to March 2014, associated to intense seismic swarms and inflation (about 22 cm of uplift). Nevertheless, these magmatic intrusions did not culminate in any eruption. Following these post-eruptive episodes, the seismic activity became less intense. Thus, for the period of this study, about 500 earthquakes with magnitude ranging from mbLG 2 to mbLG 3.9 were recorded, the ground deformation measured is of lower magnitude, still remaining a slight uplift trend in the GNSS stations up to 2017 and followed by a slight subsidence of about 1.5 cm between 2017-2019. Our purpose is to explain the ground displacements measured and the earthquake occurrence in terms of geodynamics and seismotectonic activity along the island, for the period 2015-2019. Firstly, we retrieved the geodetic velocities from the GNSS daily solutions. Secondly, we computed the 2D infinitesimal strain rates from the velocities through a triangular segmentation approach to map the deformation pattern along the respective GNSS surveys.
{"title":"2D strain rate and ground deformation modelling from continuous and survey mode GNSS data in El Hierro, Canary Islands","authors":"J. Arnoso, U. Riccardi, U. Tammaro, M. Benavent, F. G. Montesinos, E. Vélez","doi":"10.4995/jisdm2022.2022.13632","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13632","url":null,"abstract":"We present a study of the deformation pattern in El Hierro Island through the analysis of GNSS data from surveys carried out between 2015 and 2019 as well as continuous data. The last eruption in El Hierro occurred under the sea on the south rift, lasted from October 2011 to March 2012, and it was preceded by intense seismic activity and nearly 5 cm ground inflation. After this eruptive cycle, further magmatic intrusions were detected, from June 2012 to March 2014, associated to intense seismic swarms and inflation (about 22 cm of uplift). Nevertheless, these magmatic intrusions did not culminate in any eruption. Following these post-eruptive episodes, the seismic activity became less intense. Thus, for the period of this study, about 500 earthquakes with magnitude ranging from mbLG 2 to mbLG 3.9 were recorded, the ground deformation measured is of lower magnitude, still remaining a slight uplift trend in the GNSS stations up to 2017 and followed by a slight subsidence of about 1.5 cm between 2017-2019. Our purpose is to explain the ground displacements measured and the earthquake occurrence in terms of geodynamics and seismotectonic activity along the island, for the period 2015-2019. Firstly, we retrieved the geodetic velocities from the GNSS daily solutions. Secondly, we computed the 2D infinitesimal strain rates from the velocities through a triangular segmentation approach to map the deformation pattern along the respective GNSS surveys.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122163316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13846
A. Barra, Ivan Fabregat, Anna Echeverria, J. Marturia, Q. Gao, G. Luzi, M. Cuevas, P. Buxó, L. Trapero, M. Gasc, P. Espín, M. Crosetto
This paper describes the main outcomes of the European research project MOMPA (Monitoring of Ground Movements and Action Protocol). Its objective is to provide useful tools for the prevention and management of risks due to slope movements, based on the satellite monitoring InSAR (Interferometric SAR) technique. The project includes two parts: risk evaluation and the integration of InSAR in an action protocol for Civil Protections. The study area encompasses 4000 km2 including a part of the eastern Pyrenees. The project exploited medium-resolution (Sentinel-1) and high-resolution (COSMO-SkyMed) satellite images to generate ground displacement maps at interregional scale and detect the Active Deformation Areas (ADA). The ADA map was used to select movements with potential risk which were further examined by a local analysis using photo interpretation and fieldwork.
{"title":"MOMPA: InSAR monitoring in the Eastern Pyrenees","authors":"A. Barra, Ivan Fabregat, Anna Echeverria, J. Marturia, Q. Gao, G. Luzi, M. Cuevas, P. Buxó, L. Trapero, M. Gasc, P. Espín, M. Crosetto","doi":"10.4995/jisdm2022.2022.13846","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13846","url":null,"abstract":"This paper describes the main outcomes of the European research project MOMPA (Monitoring of Ground Movements and Action Protocol). Its objective is to provide useful tools for the prevention and management of risks due to slope movements, based on the satellite monitoring InSAR (Interferometric SAR) technique. The project includes two parts: risk evaluation and the integration of InSAR in an action protocol for Civil Protections. The study area encompasses 4000 km2 including a part of the eastern Pyrenees. The project exploited medium-resolution (Sentinel-1) and high-resolution (COSMO-SkyMed) satellite images to generate ground displacement maps at interregional scale and detect the Active Deformation Areas (ADA). The ADA map was used to select movements with potential risk which were further examined by a local analysis using photo interpretation and fieldwork.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126446165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13677
P. Wyszkowska, R. Duchnowski
Terrestrial laser scanning (TLS) is a measurement technique that has become popular in the last decades. Measurement results, usually as a point cloud, contain many points measured. When the TLS technique is used to determine terrain surface (e.g., by determining terrain profiles), one should realize that some points measured do not concern the terrain surface itself, but trees, shrubs, or generally the vegetation cover. Considering terrain surface determination, they should be regarded as outliers. Some other observations can also be outliers of different origins; for example, they might be disturbed by gross errors. We should consider such observation types when the data are processed. Two leading solutions in such a context are data cleaning and the application of robust estimation methods. Robust M-estimation is the most popular for the latter approach. As an alternative, one can also consider the application of Msplit estimation, in which the functional model is split into two competing ones. Hence, the paper aims to analyze how Msplit estimation can assess vertical terrain displacement based on terrain profile determination from TLS data. We consider processing data in separate sets (two measurement epochs) or one combined set, a natural approach in Msplit estimation. The analyses based on simulated TLS data proved that the first solution seems better. Furthermore, the application of Msplit estimation can also provide more satisfactory results than the classical methods used in such a context.
{"title":"Assessing vertical terrain displacement from TLS data by applying Msplit estimation – theoretical analysis","authors":"P. Wyszkowska, R. Duchnowski","doi":"10.4995/jisdm2022.2022.13677","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13677","url":null,"abstract":"Terrestrial laser scanning (TLS) is a measurement technique that has become popular in the last decades. Measurement results, usually as a point cloud, contain many points measured. When the TLS technique is used to determine terrain surface (e.g., by determining terrain profiles), one should realize that some points measured do not concern the terrain surface itself, but trees, shrubs, or generally the vegetation cover. Considering terrain surface determination, they should be regarded as outliers. Some other observations can also be outliers of different origins; for example, they might be disturbed by gross errors. We should consider such observation types when the data are processed. Two leading solutions in such a context are data cleaning and the application of robust estimation methods. Robust M-estimation is the most popular for the latter approach. As an alternative, one can also consider the application of Msplit estimation, in which the functional model is split into two competing ones. Hence, the paper aims to analyze how Msplit estimation can assess vertical terrain displacement based on terrain profile determination from TLS data. We consider processing data in separate sets (two measurement epochs) or one combined set, a natural approach in Msplit estimation. The analyses based on simulated TLS data proved that the first solution seems better. Furthermore, the application of Msplit estimation can also provide more satisfactory results than the classical methods used in such a context.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"24 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132071237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13812
Tomislav Medic, Pia Ruttner, C. Holst, A. Wieser
Terrestrial laser scanners (TLSs) offer a possibility for more automated and efficient deformation monitoring of civil engineering structures with higher spatial resolution than standard methods, as well as without the necessity of permanently installing the monitoring equipment. In such applications, scanners are usually placed so that the lines of sight are roughly aligned with the main directions of the expected deformations, and the deformations are estimated from point cloud differences between multiple epochs. This allows high sensitivity in the direction of the surface normal, but deformations along the surface are often undetected or hard to precisely quantify. In this work, we propose an algorithm based on the detection and matching of keypoints identified within TLS intensity images. This enables precise quantification of deformations along the scanned surfaces. We also present the application of the algorithm for monitoring a bridge pier of the Hochmoselbrücke in Germany, as a case study. Deformations up to about 4 cm due to thermal expansion and bending of the pier were successfully detected from scans taken throughout the day from a single location, up to 180 m from the monitored surfaces. The results agreed within a few millimeters to independent monitoring using state-of-the-art processing of TLS point clouds obtained from a different location and using a different type/brand of instrument. The newly proposed algorithm can either be used to complement existing TLS-based deformation analysis methods by adding sensitivity in certain directions, or it can be valuable as a standalone solution.
{"title":"Keypoint-based deformation monitoring using a terrestrial laser scanner from a single station: Case study of a bridge pier","authors":"Tomislav Medic, Pia Ruttner, C. Holst, A. Wieser","doi":"10.4995/jisdm2022.2022.13812","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13812","url":null,"abstract":"Terrestrial laser scanners (TLSs) offer a possibility for more automated and efficient deformation monitoring of civil engineering structures with higher spatial resolution than standard methods, as well as without the necessity of permanently installing the monitoring equipment. In such applications, scanners are usually placed so that the lines of sight are roughly aligned with the main directions of the expected deformations, and the deformations are estimated from point cloud differences between multiple epochs. This allows high sensitivity in the direction of the surface normal, but deformations along the surface are often undetected or hard to precisely quantify. In this work, we propose an algorithm based on the detection and matching of keypoints identified within TLS intensity images. This enables precise quantification of deformations along the scanned surfaces. We also present the application of the algorithm for monitoring a bridge pier of the Hochmoselbrücke in Germany, as a case study. Deformations up to about 4 cm due to thermal expansion and bending of the pier were successfully detected from scans taken throughout the day from a single location, up to 180 m from the monitored surfaces. The results agreed within a few millimeters to independent monitoring using state-of-the-art processing of TLS point clouds obtained from a different location and using a different type/brand of instrument. The newly proposed algorithm can either be used to complement existing TLS-based deformation analysis methods by adding sensitivity in certain directions, or it can be valuable as a standalone solution.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133010467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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