Pub Date : 2022-06-20DOI: 10.4995/jisdm2022.2022.13816
Gabriel Kerekes, Jakob Raschhofer, C. Harmening, H. Neuner, V. Schwieger
This contribution presents a B-spline-based approach of area-wise deformation analysis applied on elements of a double curved wooden tower. The monitored object is the Urbach Tower with a height of 14 m. Terrestrial laser scans from two epochs acquired under real-world conditions are used for approximating two jointly parametrized B-spline surfaces of the tower’s outer shell. The stochastic model of the observations used within the surface approximation is based on elementary error theory and is defined by a synthetic variance-covariance matrix (SVCM). In addition to previous work on this topic, the object’s dimension is extended from a few dm to a few m and the measurement distance ranges from 20 to 60 m. Moreover, environment specific error sources are addressed in the SVCM, revealing the effect of the object’s dimension as well as of additional elementary errors on the estimated B-spline surfaces and the subsequent deformation analysis. Based on constructed points pairs using a grid of surface parameters, rigid body movements of the object under investigation are estimated while at the same time distorted regions of the wooden tower are detected. All results of the deformation analysis are statistically verified using hypothesis tests based on the elementary error model propagated through the processing algorithms of surface estimation and deformation analysis. The results demonstrate that during the modelling and deformation analysis, the measurement noise is reduced and therefore distorted regions are detectable in a statistically correct way.
{"title":"Two-epoch TLS deformation analysis of a double curved wooden structure using approximating B-spline surfaces and fully-populated synthetic covariance matrices","authors":"Gabriel Kerekes, Jakob Raschhofer, C. Harmening, H. Neuner, V. Schwieger","doi":"10.4995/jisdm2022.2022.13816","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13816","url":null,"abstract":"This contribution presents a B-spline-based approach of area-wise deformation analysis applied on elements of a double curved wooden tower. The monitored object is the Urbach Tower with a height of 14 m. Terrestrial laser scans from two epochs acquired under real-world conditions are used for approximating two jointly parametrized B-spline surfaces of the tower’s outer shell. The stochastic model of the observations used within the surface approximation is based on elementary error theory and is defined by a synthetic variance-covariance matrix (SVCM). In addition to previous work on this topic, the object’s dimension is extended from a few dm to a few m and the measurement distance ranges from 20 to 60 m. Moreover, environment specific error sources are addressed in the SVCM, revealing the effect of the object’s dimension as well as of additional elementary errors on the estimated B-spline surfaces and the subsequent deformation analysis. Based on constructed points pairs using a grid of surface parameters, rigid body movements of the object under investigation are estimated while at the same time distorted regions of the wooden tower are detected. All results of the deformation analysis are statistically verified using hypothesis tests based on the elementary error model propagated through the processing algorithms of surface estimation and deformation analysis. The results demonstrate that during the modelling and deformation analysis, the measurement noise is reduced and therefore distorted regions are detectable in a statistically correct way.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"15 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":"122170306","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/jisdm2022.2022.13753
Awal Rahali, E. Malinverni, R. Pierdicca, A. Pierdicca, Gabriele Potenza, Matteo Lucesoli
Buildings, construction sites and civil structures need an accurate, continuous, and real time monitoring system. This necessity arises to detect dangerous situations for the structures and any occupant, especially during natural or anthropogenic events such as earthquakes or delicate phases of invasive operations such as excavations for piling. During these situations, the static and dynamic conditions of a structure and everything related to it could be impaired. The analysis and evaluation of significant displacements and deformation parameters, which are fundamental for structural controls and health monitoring, can be approached following different exchangeable procedures. Among the non-destructive monitoring techniques used in recent years, such as in this research, wireless sensors, are having a remarkable development in detecting anomalies. The acquisition of significant deformation parameters is obtained starting from the traditional topographic survey by total station and using static and dynamic sensors. Monitoring equipment concerns three-axial wireless tiltmeters which allow to measure accurately any angle of inclination in the points where they are installed in order to monitor kinematic movements during yard phases. The main purpose of this experiment is to compare data collected by tiltmeters with those obtained by the robotic total station. Three-axial accelerometers are also installed to obtain the acceleration value of the different reference points. By processing the collected data, it is proved that the final results are comparable, despite using different and completely independent monitoring systems. These integrated survey approaches demonstrate the effectiveness and efficiency of designing a monitoring system based on sensors that are installed to observe changing phenomena over the time, especially during delicate phases of invasive operations, which may represent a more widespread low-cost and reliable solution.
{"title":"Integrated survey approaches for monitoring procedures during yard phases","authors":"Awal Rahali, E. Malinverni, R. Pierdicca, A. Pierdicca, Gabriele Potenza, Matteo Lucesoli","doi":"10.4995/jisdm2022.2022.13753","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13753","url":null,"abstract":"Buildings, construction sites and civil structures need an accurate, continuous, and real time monitoring system. This necessity arises to detect dangerous situations for the structures and any occupant, especially during natural or anthropogenic events such as earthquakes or delicate phases of invasive operations such as excavations for piling. During these situations, the static and dynamic conditions of a structure and everything related to it could be impaired. The analysis and evaluation of significant displacements and deformation parameters, which are fundamental for structural controls and health monitoring, can be approached following different exchangeable procedures. Among the non-destructive monitoring techniques used in recent years, such as in this research, wireless sensors, are having a remarkable development in detecting anomalies. The acquisition of significant deformation parameters is obtained starting from the traditional topographic survey by total station and using static and dynamic sensors. Monitoring equipment concerns three-axial wireless tiltmeters which allow to measure accurately any angle of inclination in the points where they are installed in order to monitor kinematic movements during yard phases. The main purpose of this experiment is to compare data collected by tiltmeters with those obtained by the robotic total station. Three-axial accelerometers are also installed to obtain the acceleration value of the different reference points. By processing the collected data, it is proved that the final results are comparable, despite using different and completely independent monitoring systems. These integrated survey approaches demonstrate the effectiveness and efficiency of designing a monitoring system based on sensors that are installed to observe changing phenomena over the time, especially during delicate phases of invasive operations, which may represent a more widespread low-cost and reliable solution.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"69 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":"116807908","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/jisdm2022.2022.13853
Finn Linzer, H. Neuner
Employing terrestrial laser scanners (TLS) for geodetic deformation measurements requires attaining the highest possible accuracy. In this paper, we estimate the influence of varying incidence angles (IA) and materials on measurements regarding the distance component. Considering not only stochastic characteristics, the use of a scanning total station enables additionally the study of systematic distance deviations. By using the total station ocular, the device is brought into the local coordinate system of a laser tracker via position resection and intersection. The point cloud recording, with a Close-Range scanner, represents the reference. Due to transformation into a common coordinate system, defined by a laser tracker, a distance driven point comparison is possible. To test a large number of conditions an automated setup was developed. For each device, a suitable interface was implemented in the Robot Operating System. After the specimen has been set up, an automatic measurement can be performed for data acquisition. We can demonstrate that different building materials and varying IAs cause systematic distance deviations up to 3 mm magnitude. For measurement objects, this kind of correction must be considered, especially when the measurement configuration varies between measurement epochs. It can be demonstrated that the values and characteristics observed in the laboratory agree to those obtained on-site. However, the chosen approach thereby reveals previously unrecognized challenges that need to be considered for the use of TLS in high-accuracy deformation analysis.
{"title":"Transferability of an estimation procedure for distance deviations of terrestrial laser scanners from laboratory to on-site conditions","authors":"Finn Linzer, H. Neuner","doi":"10.4995/jisdm2022.2022.13853","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13853","url":null,"abstract":"Employing terrestrial laser scanners (TLS) for geodetic deformation measurements requires attaining the highest possible accuracy. In this paper, we estimate the influence of varying incidence angles (IA) and materials on measurements regarding the distance component. Considering not only stochastic characteristics, the use of a scanning total station enables additionally the study of systematic distance deviations. By using the total station ocular, the device is brought into the local coordinate system of a laser tracker via position resection and intersection. The point cloud recording, with a Close-Range scanner, represents the reference. Due to transformation into a common coordinate system, defined by a laser tracker, a distance driven point comparison is possible. To test a large number of conditions an automated setup was developed. For each device, a suitable interface was implemented in the Robot Operating System. After the specimen has been set up, an automatic measurement can be performed for data acquisition. We can demonstrate that different building materials and varying IAs cause systematic distance deviations up to 3 mm magnitude. For measurement objects, this kind of correction must be considered, especially when the measurement configuration varies between measurement epochs. It can be demonstrated that the values and characteristics observed in the laboratory agree to those obtained on-site. However, the chosen approach thereby reveals previously unrecognized challenges that need to be considered for the use of TLS in high-accuracy deformation analysis.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"1 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":"129526038","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/jisdm2022.2022.13844
L. Raffl, C. Holst
We present a method to include virtual target points from laser scanning into the point-based rigorous deformation analysis to derive precise 3D deformation vectors. This method overcomes the challenge of missing point identities in laser scans and is developed especially for geo-monitoring applications that demand an early identification of deformations at previously unknown positions. Our approach is based on virtual targets represented by local scan patches. Each patch is matched between overlapping stations and across different measurement epochs using the Iterative Closest Point Algorithm (ICP). Thus, similar to feature points, a number of homologous points is created and polar pseudo-observations are derived. This allows to integrate the observations into a free network adjustment and into a rigorous deformation analysis. We apply this method to the geo-monitoring of rock surfaces on Mt. Hochvogel where we use a scanning total station combining point-wise measurements to signalized targets and pseudo-observations derived from area-wise laser scans. In our application, numerous virtual target points could be created throughout the deformation object. The results show that the new method improves the accuracy and reliability of the subsequent rigorous deformation analysis and it, thus, allows for an early identification of deformations at geo-monitoring applications. Still there is some improvement in the selection of suitable patches needed, as the matching accuracy of the ICP strongly depends on the point distribution within the patches.
{"title":"Including virtual target points from laser scanning into the point-wise rigorous deformation analysis at geo-monitoring applications","authors":"L. Raffl, C. Holst","doi":"10.4995/jisdm2022.2022.13844","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13844","url":null,"abstract":"We present a method to include virtual target points from laser scanning into the point-based rigorous deformation analysis to derive precise 3D deformation vectors. This method overcomes the challenge of missing point identities in laser scans and is developed especially for geo-monitoring applications that demand an early identification of deformations at previously unknown positions. Our approach is based on virtual targets represented by local scan patches. Each patch is matched between overlapping stations and across different measurement epochs using the Iterative Closest Point Algorithm (ICP). Thus, similar to feature points, a number of homologous points is created and polar pseudo-observations are derived. This allows to integrate the observations into a free network adjustment and into a rigorous deformation analysis. We apply this method to the geo-monitoring of rock surfaces on Mt. Hochvogel where we use a scanning total station combining point-wise measurements to signalized targets and pseudo-observations derived from area-wise laser scans. In our application, numerous virtual target points could be created throughout the deformation object. The results show that the new method improves the accuracy and reliability of the subsequent rigorous deformation analysis and it, thus, allows for an early identification of deformations at geo-monitoring applications. Still there is some improvement in the selection of suitable patches needed, as the matching accuracy of the ICP strongly depends on the point distribution within the patches.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"118 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":"129958579","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/jisdm2022.2022.13869
Jinzhao Si, Shuangcheng Zhang, Yufen Niu
Expansive soil is a natural geological body with obvious expansion and contraction, multiple fissures and other undesirable properties. The deformation monitoring of expansive soil in high-fill areas under the combined action of wet expansion and dry contraction has become a hotspot of related research. to large-scale soil disasters. Time-series Interferometric Synthetic Aperture Radar (InSAR) technology is widely used in the monitoring of various geological hazards due to its advantages of wide coverage, high monitoring accuracy, and all-weather operation. This study takes Ankang Airport (AKA) expansive soil airport as an example. First, the ground digital elevation model (DEM) of the airport filling area was obtained by using UAV; secondly, the deformation rate and deformation time series of the expansive soil airport were obtained by using the persistent scatterer InSAR (PS-InSAR) technology; third, for the coherence In poor areas, artificial corner reflectors (CR) are arranged to increase stable scattering points; Finally, the deformation time series of feature points are extracted, combined with regional precipitation data analysis, the relationship between the periodic deformation of the airport expansive soil slope and rainfall. There is a subsidence trend along the LOS direction in the dry season, which is consistent with the expansion and contraction characteristics of expansive soils. Finally, the deformation rate is proportional to the depth of the expansive soil fill. It is judged that the existing small surface deformation and its periodic deformation distribution are caused by the combined action of the settlement after construction of the expansive soil filling area and the expansion and contraction characteristics of the expansive soil.
{"title":"PS-InSAR and UAV technology used in the stability study of Ankang expansive soil airport","authors":"Jinzhao Si, Shuangcheng Zhang, Yufen Niu","doi":"10.4995/jisdm2022.2022.13869","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13869","url":null,"abstract":"Expansive soil is a natural geological body with obvious expansion and contraction, multiple fissures and other undesirable properties. The deformation monitoring of expansive soil in high-fill areas under the combined action of wet expansion and dry contraction has become a hotspot of related research. to large-scale soil disasters. Time-series Interferometric Synthetic Aperture Radar (InSAR) technology is widely used in the monitoring of various geological hazards due to its advantages of wide coverage, high monitoring accuracy, and all-weather operation. This study takes Ankang Airport (AKA) expansive soil airport as an example. First, the ground digital elevation model (DEM) of the airport filling area was obtained by using UAV; secondly, the deformation rate and deformation time series of the expansive soil airport were obtained by using the persistent scatterer InSAR (PS-InSAR) technology; third, for the coherence In poor areas, artificial corner reflectors (CR) are arranged to increase stable scattering points; Finally, the deformation time series of feature points are extracted, combined with regional precipitation data analysis, the relationship between the periodic deformation of the airport expansive soil slope and rainfall. There is a subsidence trend along the LOS direction in the dry season, which is consistent with the expansion and contraction characteristics of expansive soils. Finally, the deformation rate is proportional to the depth of the expansive soil fill. It is judged that the existing small surface deformation and its periodic deformation distribution are caused by the combined action of the settlement after construction of the expansive soil filling area and the expansion and contraction characteristics of the expansive soil.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"1 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":"116497253","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/jisdm2022.2022.13872
Yiyan Liu, S. Acikgoz, H. Burd
Tunnelling and deep excavation activities cause ground movements. Monitoring the influence of these ground movements on nearby surface assets is a major component of urban underground construction projects. Such projects often require large-scale and comprehensive monitoring of nearby buildings to track displacements and identify structural damage. Masonry assets are particularly vulnerable to ground movements due to the low tensile strength of the material; these structures may experience unsightly cracking and structural stability issues. Current monitoring practice for these buildings is labour intensive and cannot fully characterise the response of the assets due to the limited number of measurement points. This paper presents a non-contact monitoring solution using terrestrial laser scan (TLS) data, which develops a modified non-rigid iterative closest point (N-ICP) algorithm. This algorithm optimises the displacement fields by establishing point to point correspondences that penalise non-smooth deformations and deviations from landmarks (i.e. feature points where displacements are known). The algorithm outputs rich 3D displacement fields that can be used in established assessment and decision-making procedures. To demonstrate this algorithm's ability to estimate 3D displacement fields from point clouds, several synthetic datasets are processed in this study. The results demonstrate the algorithm's potential for recovering underlying deformations with the help of landmarks and optimisation weightings.
{"title":"Terrestrial Laser Scanning based deformation monitoring for masonry buildings subjected to ground movements induced by underground construction","authors":"Yiyan Liu, S. Acikgoz, H. Burd","doi":"10.4995/jisdm2022.2022.13872","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13872","url":null,"abstract":"Tunnelling and deep excavation activities cause ground movements. Monitoring the influence of these ground movements on nearby surface assets is a major component of urban underground construction projects. Such projects often require large-scale and comprehensive monitoring of nearby buildings to track displacements and identify structural damage. Masonry assets are particularly vulnerable to ground movements due to the low tensile strength of the material; these structures may experience unsightly cracking and structural stability issues. Current monitoring practice for these buildings is labour intensive and cannot fully characterise the response of the assets due to the limited number of measurement points. This paper presents a non-contact monitoring solution using terrestrial laser scan (TLS) data, which develops a modified non-rigid iterative closest point (N-ICP) algorithm. This algorithm optimises the displacement fields by establishing point to point correspondences that penalise non-smooth deformations and deviations from landmarks (i.e. feature points where displacements are known). The algorithm outputs rich 3D displacement fields that can be used in established assessment and decision-making procedures. To demonstrate this algorithm's ability to estimate 3D displacement fields from point clouds, several synthetic datasets are processed in this study. The results demonstrate the algorithm's potential for recovering underlying deformations with the help of landmarks and optimisation weightings.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"21 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":"134255788","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/jisdm2022.2022.13656
G. Matas, A. Prades, M. Núñez-Andrés, F. Buill, N. Lantada
When monitoring deformations in natural hazards such as rockfalls and landslides, the use of 3D models has become a standard. Several geomatic techniques allow the generation of these models. However, each one has its pros and cons regarding accuracy, cost, sample frequency, etc. In this contribution a fixed-location time lapse camera system for continuous rockfall monitoring using photogrammetry has been developed as an alternative to Light Detection and Ranging (LiDAR) and ground-based interferometric synthetic-aperture radar (GB-InSAR). The usage of stereo photogrammetry allows the obtention of 3D points clouds at a low cost and with a high sample frequency, essential to detect premonitory displacements. In this work the designed system consists of three digital single-lens reflex (DSLR) cameras which collect photographs of the rock slope daily controlled by a Raspberry Pi computer using the open-source library gPhoto2. Photographs are automatically uploaded to a server using 3G network for processing. This system was implemented at Castellfollit de la Roca village (Girona province, Spain), which sits on a basaltic cliff that has shown significant rockfall intensity in recent years. The 3D models obtained will allow monitoring rockfalls frequency, premonitory displacements, and calculate the erosion rate of the slope. All technical decisions taken for the design and implementation on this specific site are discussed and first results shown.
在监测诸如落石和滑坡等自然灾害中的变形时，使用3D模型已经成为一种标准。几种地理技术允许生成这些模型。然而，每种方法在准确性、成本、采样频率等方面都有其优缺点。在这一贡献中，使用摄影测量技术开发了用于连续岩崩监测的固定位置延时相机系统，作为光探测和测距(LiDAR)和地面干涉合成孔径雷达(GB-InSAR)的替代方案。立体摄影测量的使用允许以低成本和高采样频率观察3D点云，这对于检测前兆位移至关重要。在这项工作中，设计的系统由三个数码单反(DSLR)相机组成，这些相机每天收集岩石边坡的照片，由树莓派计算机使用开源库gPhoto2控制。照片会自动上传到使用3G网络的服务器上进行处理。该系统在Castellfollit de la Roca村(西班牙赫罗纳省)实施，该村坐落在玄武岩悬崖上，近年来显示出明显的岩崩强度。获得的3D模型将允许监测落石频率，前兆位移，并计算边坡的侵蚀速率。讨论了在这个特定站点上为设计和实现所做的所有技术决策，并显示了初步结果。
{"title":"Implementation of a fixed-location time lapse photogrammetric rock slope monitoring system in Castellfollit de la Roca, Spain","authors":"G. Matas, A. Prades, M. Núñez-Andrés, F. Buill, N. Lantada","doi":"10.4995/jisdm2022.2022.13656","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13656","url":null,"abstract":"When monitoring deformations in natural hazards such as rockfalls and landslides, the use of 3D models has become a standard. Several geomatic techniques allow the generation of these models. However, each one has its pros and cons regarding accuracy, cost, sample frequency, etc. In this contribution a fixed-location time lapse camera system for continuous rockfall monitoring using photogrammetry has been developed as an alternative to Light Detection and Ranging (LiDAR) and ground-based interferometric synthetic-aperture radar (GB-InSAR). The usage of stereo photogrammetry allows the obtention of 3D points clouds at a low cost and with a high sample frequency, essential to detect premonitory displacements. In this work the designed system consists of three digital single-lens reflex (DSLR) cameras which collect photographs of the rock slope daily controlled by a Raspberry Pi computer using the open-source library gPhoto2. Photographs are automatically uploaded to a server using 3G network for processing. This system was implemented at Castellfollit de la Roca village (Girona province, Spain), which sits on a basaltic cliff that has shown significant rockfall intensity in recent years. The 3D models obtained will allow monitoring rockfalls frequency, premonitory displacements, and calculate the erosion rate of the slope. All technical decisions taken for the design and implementation on this specific site are discussed and first results shown.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"16 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":"130738254","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/jisdm2022.2022.13884
Karolina Tomaszkiewicz, T. Owerko
According to Eurocode 0 structural durability is next to ultimate and serviceability one of the basic criteria in the structural design process. This article discusses the subject of concrete cracks observation in bridge structures, as one of the factors determining their durability. The durability of bridge structures is important due to both social, economic aspects and also the defense aspects of countries. Cracking of the reinforced concrete structures is a natural effect in concrete. The aim in the design and construction of structures is not to prevent the formation of cracks, but to limit their width to acceptable values. At the same time, there is a need for structure tests that allow for non-contact, fast measurements and algorithms that allow for efficient analysis of large amounts of measurement data. Deep machine learning algorithms can be used here. They can be used to analyse data which are acquired by means of photogrammetric methods (especially helpful during construction to inventory concealed works). Moreover, they can also be applied to standard data acquisition methods, consisting in photographing objects damage during works acceptance or periodic inspections. This paper discusses the application of deep machine learning to assess the condition of bridge structures based on photographs of object damage. The use of this method makes it possible to observe the rate and extent of damage development. Consequently, this method makes it possible to predict the development of damage in time and space in order to prevent failures and take structures out of service.
{"title":"Deep machine learning in bridge structures durability analysis","authors":"Karolina Tomaszkiewicz, T. Owerko","doi":"10.4995/jisdm2022.2022.13884","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13884","url":null,"abstract":"According to Eurocode 0 structural durability is next to ultimate and serviceability one of the basic criteria in the structural design process. This article discusses the subject of concrete cracks observation in bridge structures, as one of the factors determining their durability. The durability of bridge structures is important due to both social, economic aspects and also the defense aspects of countries. Cracking of the reinforced concrete structures is a natural effect in concrete. The aim in the design and construction of structures is not to prevent the formation of cracks, but to limit their width to acceptable values. At the same time, there is a need for structure tests that allow for non-contact, fast measurements and algorithms that allow for efficient analysis of large amounts of measurement data. Deep machine learning algorithms can be used here. They can be used to analyse data which are acquired by means of photogrammetric methods (especially helpful during construction to inventory concealed works). Moreover, they can also be applied to standard data acquisition methods, consisting in photographing objects damage during works acceptance or periodic inspections. This paper discusses the application of deep machine learning to assess the condition of bridge structures based on photographs of object damage. The use of this method makes it possible to observe the rate and extent of damage development. Consequently, this method makes it possible to predict the development of damage in time and space in order to prevent failures and take structures out of service.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"1 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":"131125158","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/jisdm2022.2022.13883
A. M. Ruiz-Armenteros, J. M. Delgado-Blasco, M. Bakon, Francisco Lamas-Fernández, Miguel Marchamalo-Sacristán, A. J. Gil-Cruz, J. Papčo, Beatriz González-Rodrigo, M. Lazecký, D. Perissin, J. J. Sousa
The monitoring procedures with different geotechnical/structural sensors and classical geodetic techniques including GNSS are the usual practices in most of the dams where these controls are established. Other geomatic techniques such as TLS, GB-SAR and multi-temporal InSAR (MT-InSAR), allow the determination of 3D displacements with the advantage of covering a large number of control points. In particular, MT-InSAR techniques enable the detection of displacements at a very low cost compared to other techniques, and without the need for field work or the installation of special equipment. In addition, they can provide a single source of information on the stability of the dam when monitoring programs are not carried out due to lack of funding, resources or other reasons. These techniques provide measurement uncertainties of the order of 1 mm/year, interpreting time series of interferometric phases of coherent reflectors present in the area, called Persistent Scatterers. In this work, we present the adaptation and application of MT-InSAR techniques to monitor embankment dams, obtaining vertical displacements, characterizing their consolidation rates, and allowing the identification of potential problems surrounding the reservoir that require further field investigation. This study is part of the ReMoDams project, a Spanish research initiative developed for monitoring dam structural stability from space using satellite radar interferometry.
{"title":"Monitoring embankment dams from space using satellite radar interferometry: Case studies from RemoDams project","authors":"A. M. Ruiz-Armenteros, J. M. Delgado-Blasco, M. Bakon, Francisco Lamas-Fernández, Miguel Marchamalo-Sacristán, A. J. Gil-Cruz, J. Papčo, Beatriz González-Rodrigo, M. Lazecký, D. Perissin, J. J. Sousa","doi":"10.4995/jisdm2022.2022.13883","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13883","url":null,"abstract":"The monitoring procedures with different geotechnical/structural sensors and classical geodetic techniques including GNSS are the usual practices in most of the dams where these controls are established. Other geomatic techniques such as TLS, GB-SAR and multi-temporal InSAR (MT-InSAR), allow the determination of 3D displacements with the advantage of covering a large number of control points. In particular, MT-InSAR techniques enable the detection of displacements at a very low cost compared to other techniques, and without the need for field work or the installation of special equipment. In addition, they can provide a single source of information on the stability of the dam when monitoring programs are not carried out due to lack of funding, resources or other reasons. These techniques provide measurement uncertainties of the order of 1 mm/year, interpreting time series of interferometric phases of coherent reflectors present in the area, called Persistent Scatterers. In this work, we present the adaptation and application of MT-InSAR techniques to monitor embankment dams, obtaining vertical displacements, characterizing their consolidation rates, and allowing the identification of potential problems surrounding the reservoir that require further field investigation. This study is part of the ReMoDams project, a Spanish research initiative developed for monitoring dam structural stability from space using satellite radar interferometry.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"69 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":"127407211","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/jisdm2022.2022.13755
E. Vassilakis, A. Konsolaki, S. Petrakis, Evangelia Kotsi, C. Filis, Stelios Lozios, E. Lekkas
The coastal area of Myrtos beach, is a very popular Natura protected area at the Northern part of Cephalonia Island, in W. Greece, which suffered severe damages during the Medicane named after “Ianos”, that affected the Greek territory in September 2020. Most of the steep slope area, which hosts the road that leads to the beach area itself were extensively covered by debris due to mudflows, interrupting aggressively the road connection with the inland network. The use of Unmanned Aerial Systems proved to be an ideal way of mapping quite small areas, with limited access to road networks. The generation of ultra-high resolution spatial products seems to be optimal for mapping and quantifying mass movements that cover areas ranging from less than one square kilometer up to few square kilometers. The aim of such a multi-temporal study, which is described herein, contains aerial image data collection and analysis, before and after the catastrophic event. It is leading to the quantification of the surface topographic changes, by generating a time series of point clouds, after creating several terrain models along with ortho-photo-mosaics, based on Structure-from-Motion photogrammetric techniques. The digital comparison of the co-registered photogrammetric products showed that significant surface alterations have taken place due to the 2020 Medicane. The diachronic point clouds led to the detection and quantification of elevation changes, mainly at the central part of the area of interest, whereas the elevation values of the point clouds were found rather altered, before and after “Ianos”, either positively (deposition) or negatively (erosion), delineating the areas that suffered surface changes.
{"title":"4D point cloud analysis of the September 2020 Medicane impact on Myrtos beach in Cephalonia, Greece","authors":"E. Vassilakis, A. Konsolaki, S. Petrakis, Evangelia Kotsi, C. Filis, Stelios Lozios, E. Lekkas","doi":"10.4995/jisdm2022.2022.13755","DOIUrl":"https://doi.org/10.4995/jisdm2022.2022.13755","url":null,"abstract":"The coastal area of Myrtos beach, is a very popular Natura protected area at the Northern part of Cephalonia Island, in W. Greece, which suffered severe damages during the Medicane named after “Ianos”, that affected the Greek territory in September 2020. Most of the steep slope area, which hosts the road that leads to the beach area itself were extensively covered by debris due to mudflows, interrupting aggressively the road connection with the inland network. The use of Unmanned Aerial Systems proved to be an ideal way of mapping quite small areas, with limited access to road networks. The generation of ultra-high resolution spatial products seems to be optimal for mapping and quantifying mass movements that cover areas ranging from less than one square kilometer up to few square kilometers. The aim of such a multi-temporal study, which is described herein, contains aerial image data collection and analysis, before and after the catastrophic event. It is leading to the quantification of the surface topographic changes, by generating a time series of point clouds, after creating several terrain models along with ortho-photo-mosaics, based on Structure-from-Motion photogrammetric techniques. The digital comparison of the co-registered photogrammetric products showed that significant surface alterations have taken place due to the 2020 Medicane. The diachronic point clouds led to the detection and quantification of elevation changes, mainly at the central part of the area of interest, whereas the elevation values of the point clouds were found rather altered, before and after “Ianos”, either positively (deposition) or negatively (erosion), delineating the areas that suffered surface changes.","PeriodicalId":404487,"journal":{"name":"Proceedings of the 5th Joint International Symposium on Deformation Monitoring - JISDM 2022","volume":"340 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":"123553327","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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