scholarly journals Phased Reconnaissance Approach to Documenting Landslides following the 2016 Central Italy Earthquakes

2018 ◽  
Vol 34 (4) ◽  
pp. 1693-1719 ◽  
Author(s):  
Kevin W. Franke ◽  
Bret N. Lingwall ◽  
Paolo Zimmaro ◽  
Robert E. Kayen ◽  
Paolo Tommasi ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Central Italy ◽  
Three Dimensional ◽  
Case Histories ◽  
Large Area ◽  
Rock Falls ◽  
Central Apennines ◽  
Central Italy Earthquake ◽  
Surface Models ◽  
Seismically Induced Landslides

The 2016 Central Italy earthquake sequence caused numerous landslides over a large area in the Central Apennines. As a result, the Geotechnical Extreme Events Reconnaissance Association (GEER) organized post-earthquake reconnaissance missions to collect perishable data. Given the challenging conditions following the earthquakes, the GEER team implemented a phased reconnaissance approach. This paper illustrates this approach and how it was used to document the largest and most impactful seismically induced landslides. This phased approach relied upon satellite-based interferometric damage proxy maps, preliminary published reports of observed landslides, digital imaging from small unmanned aerial vehicles (UAVs), traditional manual observations, and terrestrial laser scanning. Data collected from the reconnoitered sites were used to develop orthophotos and meshed three-dimensional digital surface models. These products can provide valuable information such as accurate measurements of landslide ground movements in complex topographic geometries or boulder runout distances from rock falls. The paper describes three significant landslide case histories developed and documented with the phased approach: Nera Valley, Village of Pescara del Tronto, and near the villages of Crognaleto and Cervaro.

scholarly journals COMPARING 3D DIGITAL TECHNOLOGIES FOR ARCHAEOLOGICAL FIELDWORK DOCUMENTATION. THE CASE OF THESSALONIKI TOUMBA EXCAVATION, GREECE

2021 ◽  
Vol XLVI-M-1-2021 ◽  
pp. 713-720
Author(s):  
A. Stamnas ◽  
D. Kaimaris ◽  
C. Georgiadis ◽  
P. Patias
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Data ◽  
3D Measurement ◽  
Advanced Technologies ◽  
Surface Models ◽  
Historic Structures ◽  
Aerial Vehicle ◽  
Close Range ◽  
Documentation Tool

Abstract. Nowadays, there are many methods and techniques for the documentation and the restoration of historic structures and historical artifacts that are commonly used due to their completeness, accuracy and fastness. The use of advanced 3D measurement technologies, by either using terrestrial or aerial means of acquiring digital data, has become an efficient and reliable documentation tool. Within this context, this study focuses on combining terrestrial laser scanning, unmanned aerial vehicle photogrammetry, close-range photogrammetry and topographic surveying, and comparing the associated digital data for archaeological fieldwork documentation. The data collected during the Thessaloniki Toumba Excavation (Greece) provided accurate digital surface models and photo-realistic three-dimensional outputs of archaeological trenches. The data elaboration enabled new inferences and knowledge to be gained through the implementation of advanced technologies in heritage documentation.

scholarly journals Three-Dimensional Unique-Identifier-Based Automated Georeferencing and Coregistration of Point Clouds in Underground Mines

2021 ◽  
Vol 13 (16) ◽  
pp. 3145
Author(s):  
Sarvesh Kumar Singh ◽  
Bikram Pratap Banerjee ◽  
Simit Raval
Keyword(s):  
Convergence Rate ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Reference Points ◽  
Underground Mines ◽  
Sensor Calibration ◽  
3D Registration ◽  
Rock Falls

Spatially referenced and geometrically accurate laser scans are essential for mapping and monitoring applications in underground mines to ensure safe and smooth operation. However, obtaining an absolute 3D map in an underground mine environment is challenging using laser scanning due to the unavailability of global navigation satellite system (GNSS) signals. Consequently, applications that require georeferenced point cloud or coregistered multitemporal point clouds such as detecting changes, monitoring deformations, tracking mine logistics, measuring roadway convergence rate and evaluating construction performance become challenging. Current mapping practices largely include a manual selection of discernable reference points in laser scans for georeferencing and coregistration which is often time-consuming, arduous and error-prone. Moreover, challenges in obtaining a sensor positioning framework, the presence of structurally symmetric layouts and highly repetitive features (such as roof bolts) makes the multitemporal scans difficult to georeference and coregister. This study aims at overcoming these practical challenges through development of three-dimensional unique identifiers (3DUIDs) and a 3D registration (3DReG) workflow. Field testing of the developed approach in an underground coal mine has been found effective with an accuracy of 1.76 m in georeferencing and 0.16 m in coregistration for a scan length of 850 m. Additionally, automatic extraction of mine roadway profile has been demonstrated using 3DUID which is often a compliant and operational requirement for mitigating roadway related hazards that includes roadway convergence rate, roof/rock falls, floor heaves and vehicle clearance for collision avoidance. Potential applications of 3DUID include roadway profile extraction, guided automation, sensor calibration, reference targets for a routine survey and deformation monitoring.

scholarly journals APPLICABILITY ANALYSIS OF CLOTH SIMULATION FILTERING ALGORITHM FOR MOBILE LIDAR POINT CLOUD

2018 ◽  
Vol XLII-3 ◽  
pp. 107-111 ◽  
Author(s):  
S. Cai ◽  
W. Zhang ◽  
J. Qi ◽  
P. Wan ◽  
J. Shao ◽  
...  
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Point Clouds ◽  
Airborne Lidar ◽  
Cloth Simulation ◽  
Large Area ◽  
Three Samples ◽  
Separate Point ◽  
A New Technique

Classifying the original point clouds into ground and non-ground points is a key step in LiDAR (light detection and ranging) data post-processing. Cloth simulation filtering (CSF) algorithm, which based on a physical process, has been validated to be an accurate, automatic and easy-to-use algorithm for airborne LiDAR point cloud. As a new technique of three-dimensional data collection, the mobile laser scanning (MLS) has been gradually applied in various fields, such as reconstruction of digital terrain models (DTM), 3D building modeling and forest inventory and management. Compared with airborne LiDAR point cloud, there are some different features (such as point density feature, distribution feature and complexity feature) for mobile LiDAR point cloud. Some filtering algorithms for airborne LiDAR data were directly used in mobile LiDAR point cloud, but it did not give satisfactory results. In this paper, we explore the ability of the CSF algorithm for mobile LiDAR point cloud. Three samples with different shape of the terrain are selected to test the performance of this algorithm, which respectively yields total errors of 0.44 %, 0.77 % and1.20 %. Additionally, large area dataset is also tested to further validate the effectiveness of this algorithm, and results show that it can quickly and accurately separate point clouds into ground and non-ground points. In summary, this algorithm is efficient and reliable for mobile LiDAR point cloud.

scholarly journals Ground deformation and fault modeling of the 2016 sequence (24 Aug. – 30 Oct.) in central Apennines (Central Italy)

2017 ◽  
Vol 51 ◽  
pp. 76 ◽  
Author(s):  
Spyros Pavlides ◽  
Alexandros Chatzipetros ◽  
George Papathanasiou ◽  
George Georgiadis ◽  
Sotiris Sboras ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Hanging Wall ◽  
Central Italy ◽  
3D Models ◽  
Fault Reactivation ◽  
Aerial Images ◽  
Rock Falls ◽  
Central Apennines ◽  
Seismogenic Sources ◽  
Stress Changes

A chain fault reactivation took place in central Apennines, from August 24 to October 30, 2016, producing five moderate-to-strong earthquakes ranging from Mw5.5 to Mw6.6. This paper presents the results from the study of the ground co-seismic ruptures around the Monte Vettore and Vettoretto, and Norcia. Surface co-seismic ruptures, were observed in the Vettore and Vettoretto segment of the fault for some kilometers (~7 km) in the August earthquakes, which were partly re-activated  and  expanded  northward  during  the  October  earthquakes.  Ruptures  with  5-15  cm displacements are observed both in scree and weathered mantle (elluvium) and the bedrock, mainly fragmented carbonate rocks with small tectonic surfaces. After the October seismic sequence the co-seismic displacement doubled and reached more than 50cm. Oblique low-altitude aerial images were acquired at several sites using a UAV and 3D models were constructed using photogrammetric extrapolation. Numerous observed and mapped rock falls, slides of earth-materials etc, occur mainly along the mountain roads, on artificial slopes. They were studied with preliminary mapping from satellite imagery, and examples are presented of large landslides in the epicentral region with pre and after- the earthquake images. The first four events are associated with four individual fault segments respectively, all aligned along the mountain-fronts of Mt Gorzano and Mt Vettore. The last fifth and strongest event was the result of linkage and breaching of the previous fault segments. We modelled the fault segments intofive seismogenic sources in order to calculate the post-sequence static stress changes produced by the five seismogenic sources (or source faults) to the surrounding faults (receiver faults). Our results suggest possible triggering effects for neighbouring faults located along the strike of the source faults and delay effects for faults which are directly located either on the footwall or hanging-wall.

scholarly journals Hybrid laser-assisted forming process for ultralight three-dimensional glass elements

2021 ◽  
Vol 255 ◽  
pp. 12007
Author(s):  
Robin Hassel ◽  
Andrea Barz ◽  
Jens Bliedtner ◽  
Jörg Steuer ◽  
Hans Pitcha ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Continuous Process ◽  
Three Dimensional ◽  
Scanning System ◽  
Large Area ◽  
Forming Process ◽  
Thin Glass ◽  
Display Technology ◽  
Application Fields ◽  
Laser Scanning System

As part of a research project, a new hybrid forming process for ultrathin three-dimensional glass elements was developed. In a continuous process chain, the three-part procedure enables large-area gravity-assisted bending of thin glass, partial deep-drawing of individual small structures using CO2 laser radiation and cutting of flexible inner and outer contours. Using an experimental setup with a laser scanning system, novel component designs can be generated in a highly flexible and reproducible manner. This can open up new application fields or expand existing ones, for example in the area of cover glasses for display technology.

scholarly journals Aerodromų kliūtis ribojančių paviršių modeliavimas geoinformacinių technologijų priemonėmis

2011 ◽  
Vol 56 ◽  
pp. 119-127
Author(s):  
Viktoras Paliulionis
Keyword(s):  
Spatial Data ◽  
Laser Scanning ◽  
3D Visualization ◽  
Three Dimensional ◽  
Gis Technology ◽  
Site Model ◽  
Modelling Analysis ◽  
Surface Models ◽  
New Construction ◽  
Scanning Lidar

Trijų matavimų (3D) erdvinių duomenų modeliavimas, analizė ir vizualizavimas naudojami daugelyje sričių. Šiame straipsnyje nagrinėjami klausimai, susiję su aerodromų kliūtis ribojančių paviršių (apsaugos zonų) modeliavimu, siekiant nustatyti kliūtis, kurios gali kelti pavojų orlaivių skrydžiams. Pademonstruota, kaip šiuos klausimus galima spręsti naudojantis skaitmeniniu reljefo, vietovės ir kliūtis ribojančių paviršių modeliavimu, 3D vizualizavimu ir analize. Siūlomas skaitmeninių vietovės modeliųsudarymo algoritmas leidžia efektyviai naudoti lazerinio skenavimo (LIDAR) taškų duomenis. Aprašyta bandomoji sistema „Akis-AER“, kurios paskirtis – padėti nustatyti kliūtis aplink aerodromus ir įvertinti planuojamus statyti ar aukštinamus statinius aerodromų apsaugos zonose.The Use of GIS Technology in Modelling Obstacle Limitation Surfaces of an AerodromeViktoras Paliulionis SummaruThere are many domains where the modelling, analysis and visualization of three-dimensional spatial data can be useful. The paper discusses the issues concerning the modelling of aerodrome obstacle limitation surfaces. They can help to detect obstacle in the flight path of an aircraft. To this end, digital relief and site models need to be created together with obstacle limitation surface models. A fast and effective algorithm of creating three-dimensional digital site model which uses airborne laser scanning (LIDAR) data is proposed. The 3D visualization and analysis of the model are also discussed. The paper presents the experimental Akis-AER software designed to detect potential obstacles around an aerodrome and assess whether it is safe to install a new construction or to increase the height of the existing one in the navigating space around the aerodrome.

scholarly journals Processing Strategy and Comparative Performance of Different Mobile LiDAR System Grades for Bridge Monitoring: A Case Study

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7550
Author(s):  
Yi-Chun Lin ◽  
Jidong Liu ◽  
Yi-Ting Cheng ◽  
Seyyed Meghdad Hasheminasab ◽  
Timothy Wells ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Lidar Data ◽  
Large Area ◽  
Comparative Performance ◽  
High Resolution Data ◽  
Bridge Monitoring ◽  
System Calibration ◽  
Wide Range ◽  
The Impact

Collecting precise as-built data is essential for tracking construction progress. Three-dimensional models generated from such data capture the as-is conditions of the structures, providing valuable information for monitoring existing infrastructure over time. As-built data can be acquired using a wide range of remote sensing technologies, among which mobile LiDAR is gaining increasing attention due to its ability to collect high-resolution data over a relatively large area in a short time. The quality of mobile LiDAR data depends not only on the grade of onboard LiDAR scanners but also on the accuracy of direct georeferencing information and system calibration. Consequently, millimeter-level accuracy is difficult to achieve. In this study, the performance of mapping-grade and surveying-grade mobile LiDAR systems for bridge monitoring is evaluated against static laser scanners. Field surveys were conducted over a concrete bridge where grinding was required to achieve desired smoothness. A semi-automated, feature-based fine registration strategy is proposed to compensate for the impact of georeferencing and system calibration errors on mobile LiDAR data. Bridge deck thickness is evaluated using surface segments to minimize the impact of inherent noise in the point cloud. The results show that the two grades of mobile LiDAR delivered thickness estimates that are in agreement with those derived from static laser scanning in the 1 cm range. The mobile LiDAR data acquisition took roughly five minutes without having a significant impact on traffic, while the static laser scanning required more than three hours.

Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

1990 ◽  
Vol 48 (3) ◽  
pp. 166-167
Author(s):  
J. Holy ◽  
G. Schatten
Keyword(s):  
Confocal Microscopy ◽  
Mitotic Spindle ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Two Dimensions ◽  
Embryonic Cells ◽  
Mitotic Spindles ◽  
Cleavage Division ◽  
Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

Automated 3-D cell population analysis in thick tissue sections using laser-scanning confocal-microscopy data

1993 ◽  
Vol 51 ◽  
pp. 562-563
Author(s):  
Hakan Ancin
Keyword(s):  
Laser Scanning ◽  
Population Analysis ◽  
Three Dimensional ◽  
Large Data ◽  
Laser Scanning Confocal Microscopy ◽  
Tissue Slices ◽  
Scanning Confocal Microscopy ◽  
Tissue Sections ◽  
Spatially Adaptive ◽  
Microscopy Data

This paper presents methods for performing detailed quantitative automated three dimensional (3-D) analysis of cell populations in thick tissue sections while preserving the relative 3-D locations of cells. Specifically, the method disambiguates overlapping clusters of cells, and accurately measures the volume, 3-D location, and shape parameters for each cell. Finally, the entire population of cells is analyzed to detect patterns and groupings with respect to various combinations of cell properties. All of the above is accomplished with zero subjective bias.In this method, a laser-scanning confocal light microscope (LSCM) is used to collect optical sections through the entire thickness (100 - 500μm) of fluorescently-labelled tissue slices. The acquired stack of optical slices is first subjected to axial deblurring using the expectation maximization (EM) algorithm. The resulting isotropic 3-D image is segmented using a spatially-adaptive Poisson based image segmentation algorithm with region-dependent smoothing parameters. Extracting the voxels that were labelled as "foreground" into an active voxel data structure results in a large data reduction.

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