scholarly journals INTEGRATION OF TERRESTRIAL AND UAV PHOTOGRAMMETRY FOR THE ASSESSMENT OF COLLAPSE RISK IN ALPINE GLACIERS

2018 ◽  
Vol XLII-3/W4 ◽  
pp. 445-452 ◽  
Author(s):  
M. Scaioni ◽  
L. Barazzetti ◽  
M. Corti ◽  
J. Crippa ◽  
R. S. Azzoni ◽  
...  
Keyword(s):  
Global Warming ◽  
Structure From Motion ◽  
3D Model ◽  
Point Clouds ◽  
Italian Alps ◽  
Technical Aspects ◽  
Alpine Glaciers ◽  
Multi Temporal ◽  
Glacier Ice

<p><strong>Abstract.</strong> The application of Structure-from-Motion photogrammetry with ground-based and UAV-based camera stations can be effectively exploited for modeling the topographic surface of Alpine glaciers. Multi-temporal repeated surveys may lead to geometric models that may be applied to analyze the glacier retreat under global warming conditions. Here the case study of Forni Glacier in the Italian Alps is presented. Thanks to the integration of point clouds obtained from the independent photogrammetric processing of ground-based and UAV blocks of images (captured on 2016), a complete 3D reconstruction also including vertical and sub-vertical surfaces has been achieved. This 3D model, compared to a second model obtained from a ground-based photogrammetric survey on September 2017, has been exploited to understand the precursory signal of a big collapse that might have involved tourists and hikers visiting the glacier ice tongue during summer. In addition to some technical aspects related to the acquisition and processing of photogrammetric data of glaciers, this paper highlights how Structure-from-Motion photogrammetry may help evaluate the risk of collapse in Alpine glaciers.</p>

scholarly journals Quantifying ice cliff evolution with multi-temporal point clouds on the debris-covered Khumbu Glacier, Nepal

2017 ◽  
Vol 63 (241) ◽  
pp. 823-837 ◽  
Author(s):  
C. SCOTT WATSON ◽  
DUNCAN J. QUINCEY ◽  
MARK W. SMITH ◽  
JONATHAN L. CARRIVICK ◽  
ANN V. ROWAN ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Structure From Motion ◽  
Point Clouds ◽  
Full Study ◽  
Multi Temporal ◽  
Glacier Ice ◽  
Glacier Ablation ◽  
Cliff Retreat

ABSTRACTMeasurements of glacier ice cliff evolution are sparse, but where they do exist, they indicate that such areas of exposed ice contribute a disproportionate amount of melt to the glacier ablation budget. We used Structure from Motion photogrammetry with Multi-View Stereo to derive 3-D point clouds for nine ice cliffs on Khumbu Glacier, Nepal (in November 2015, May 2016 and October 2016). By differencing these clouds, we could quantify the magnitude, seasonality and spatial variability of ice cliff retreat. Mean retreat rates of 0.30–1.49 cm d−1 were observed during the winter interval (November 2015–May 2016) and 0.74–5.18 cm d−1 were observed during the summer (May 2016–October 2016). Four ice cliffs, which all featured supraglacial ponds, persisted over the full study period. In contrast, ice cliffs without a pond or with a steep back-slope degraded over the same period. The rate of thermo-erosional undercutting was over double that of subaerial retreat. Overall, 3-D topographic differencing allowed an improved process-based understanding of cliff evolution and cliff-pond coupling, which will become increasingly important for monitoring and modelling the evolution of thinning debris-covered glaciers.

scholarly journals LOCAL AND GENERAL MONITORING OF FORNI GLACIER (ITALIAN ALPS) USING MULTI-PLATFORM STRUCTURE-FROM-MOTION PHOTOGRAMMETRY

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 1547-1554 ◽  
Author(s):  
M. Scaioni ◽  
M. Corti ◽  
G. Diolaiuti ◽  
D. Fugazza ◽  
M. Cernuschi
Keyword(s):  
Structure From Motion ◽  
Accuracy Assessment ◽  
Laser Scanner ◽  
High Mountain ◽  
Italian Alps ◽  
Mountain Areas ◽  
Medium Resolution ◽  
Stereo Photogrammetry ◽  
Glacier Ice ◽  
Global And Local

Experts from the University of Milan have been investigating Forni Glacier in the Italian alps for decades, resulting in the archive of a cumbersome mass of observed data. While the analysis of archive maps, medium resolution satellite images and DEM’s may provide an overview of the long-term processes, the application of close-range sensing techniques offers the unprecedented opportunity to operate a 4D reconstruction of the glacier geometry at both global and local levels. In the latest years the availability of high-resolution DEM's from stereo-photogrammetry (2007) and UAV-photogrammetry (2014 and 2016) has allowed an improved analysis of the glacier ice-mass balance within time. During summer 2016 a methodology to record the local disruption processes has been investigated. The presence of vertical and sub-vertical surfaces has motivated the use of Structure-from-Motion Photogrammetry from ground-based stations, which yielded results comparable to the ones achieved using a long-range terrestrial laser scanner. This technique may be assumed as benchmarking for accuracy assessment, but is more difficult to be operated in high-mountain areas. Nevertheless, the measurement of GCP’s for the terrestrial photogrammetric project has revealed to be a complex task, involving the need of a total station a GNSS. The effect of network geometry on the final output has also been investigated for SfM-Photogrammetry, considering the severe limitations implied in the Alpine environment.

scholarly journals Suitability Study of Structure-from-Motion for the Digitisation of Architectural (Heritage) Spaces to Apply Divergent Photograph Collection

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1981
Author(s):  
Juan Moyano ◽  
Juan E. Nieto-Julián ◽  
Daniel Antón ◽  
Elena Cabrera ◽  
David Bienvenido-Huertas ◽  
...  
Keyword(s):  
Structure From Motion ◽  
Laser Scanning ◽  
Low Cost ◽  
Point Clouds ◽  
Control Points ◽  
Architectural Heritage ◽  
High Definition ◽  
Symmetrical Configuration ◽  
Architectural Spaces

The digitisation of architectural heritage has experienced a great development of low-cost and high-definition data capture technologies, thus enabling the accurate and effective modelling of complex heritage assets. Accordingly, research has identified the best methods to survey historic buildings, but the suitability of Structure-from-Motion/Multi-view-Stereo (SfM/MVS) for interior square symmetrical architectural spaces is unexplored. In contrast to the traditional SfM surveying for which the camera surrounds the object, the photograph collection approach is divergent in courtyards. This paper evaluates the accuracy of SfM point clouds against Terrestrial Laser Scanning (TLS) for these large architectural spaces with a symmetrical configuration, with the main courtyard of Casa de Pilatos in Seville, Spain, as a case study. Two different SfM surveys were conducted: (1) Without control points, and (2) referenced using a total station. The first survey yielded unacceptable results: A standard deviation of 0.0576 m was achieved in the northwest sector of the case study, mainly because of the difficulty of aligning the SfM and TLS data due to the way they are produced. This value could be admissible depending on the purpose of the photogrammetric model.

scholarly journals Vision metrology and Structure from Motion for archaeological heritage 3D reconstruction: a Case Study of various Roman mosaics

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (3) ◽  
pp. 35 ◽  
Author(s):  
Mauro Lo Brutto ◽  
Gino Dardanelli
Keyword(s):  
Computer Vision ◽  
3D Reconstruction ◽  
Structure From Motion ◽  
3D Model ◽  
3D Measurement ◽  
Archaeological Heritage ◽  
Very High ◽  
Archaeological Objects ◽  
3D Mosaics

<p class="Abstract">Vision metrology and computer vision can be successfully used for archaeological heritage 3D reconstruction in very high precision 3D measurement projects. Of those archaeological objects requiring very accurate measurements (&lt;1 mm), ancient mosaics comprise some of the most important. The aim of this paper is to assess the photogrammetric/computer vision approach in a vision metrology context as part of a 3D mosaics survey. In order to evaluate the optimal photogrammetric/computer vision workflow in this work, three different surveys were performed on three mosaics of different sizes and locations. Two of these are stored at the <em>Antonino Salinas</em> Regional Archaeological Museum in Palermo (Italy) and the other is located at the <em>Baglio Anselmi</em> Regional Archaeological Museum in Marsala (Italy). The mosaics survey was undertaken in order to obtain a very detailed 3D model and a full-scale ortho-image (scale 1:1), which would be useful for documentation and restoration processes. The research involved an evaluation of the potential and the related issues of the photogrammetric/computer vision approach for 3D mosaic documentation, particularly regarding the issue of camera calibration.</p>

scholarly journals A PROMPT METHODOLOGY TO GEOREFERENCE COMPLEX HYPOGEA ENVIRONMENTS

2017 ◽  
Vol XLII-2/W3 ◽  
pp. 639-644 ◽  
Author(s):  
S. Troisi ◽  
V. Baiocchi ◽  
S. Del Pizzo ◽  
F. Giannone
Keyword(s):  
Structure From Motion ◽  
3D Model ◽  
Drainage System ◽  
Bundle Adjustment ◽  
Field Of View ◽  
Wide Field ◽  
Underground Structures ◽  
Forward Motion ◽  
Wide Field Of View

Actually complex underground structures and facilities occupy a wide space in our cities, most of them are often unsurveyed; cable duct, drainage system are not exception. Furthermore, several inspection operations are performed in critical air condition, that do not allow or make more difficult a conventional survey. In this scenario a prompt methodology to survey and georeferencing such facilities is often indispensable. <br><br> A visual based approach was proposed in this paper; such methodology provides a 3D model of the environment and the path followed by the camera using the conventional photogrammetric/Structure from motion software tools. The key-role is played by the lens camera; indeed, a fisheye system was employed to obtain a very wide field of view (FOV) and therefore high overlapping among the frames. The camera geometry is in according to a forward motion along the axis camera. Consequently, to avoid instability of bundle adjustment algorithm a preliminary calibration of camera was carried out. A specific case study was reported and the accuracy achieved.

scholarly journals 3D GLACIER MAPPING BY MEANS OF SATELLITE STEREO IMAGES: THE BELVEDERE GLACIER CASE STUDY IN THE ITALIAN ALPS

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 1073-1079
Author(s):  
F. Giulio Tonolo ◽  
A. Cina ◽  
A. Manzino ◽  
M. Fronteddu
Keyword(s):  
Accuracy Assessment ◽  
Control Point ◽  
Surface Model ◽  
Stereo Pair ◽  
Italian Alps ◽  
Positional Accuracy ◽  
Multi Temporal ◽  
Fit For Purpose ◽  
The Impact

Abstract. The authors group is within the Glacier Lab of Politecnico di Torino (part of the CC-LAB, a laboratory for climate change monitoring), which is working on glacier monitoring since 2016, mainly exploiting Geomatics techniques to measure the extent and to model the surface of glaciers over the years. Measurement campaigns were carried out within the ASP (Alta Scuola Politecnica – Poliecnico di Torino e Milano) DREAM projects (Drone tEchnnology for wAter resources and hydrologic hazard Monitoring) The manuscript is focused on a specific case study related to the Belvedere glacier, a valley glacier located in northern Italy.In the framework of the Belvedere glacier monitoring, several Geomatics approaches have already been applied in the last four years by the cc-glacier-lab and DREAM Projects with the goal to monitor both the extent of the glacier and its surface. Such monitoring enables the multi-temporal comparison of the glacier digital surface model (DSM), highlighting areas of ice loss and gain. Considering the limitations of aerial surveys in high altitude environments, the authors started assessing the suitability of a satellite based approach, mainly focusing on positional accuracy assessment. The paper is focused on a monitoring based on a high resolution (0.5 m) satellite optical stereo pair. Several tests were carried out with the goal to test the 3D positional accuracies, assessing the impact of different configurations of Ground Control Point (GCP) in terms of numerosity and distribution and focusing on the DSM validation. The results demonstrated the fit-for-purpose of a satellite-based approach for glacier monitoring.

scholarly journals MONITORING ALPINE GLACIERS FROM CLOSE-RANGE TO SATELLITE SENSORS

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 1803-1810
Author(s):  
V. Yordanov ◽  
D. Fugazza ◽  
R. S. Azzoni ◽  
M. Cernuschi ◽  
M. Scaioni ◽  
...  
Keyword(s):  
Point Clouds ◽  
Data Sets ◽  
Alpine Glaciers ◽  
Medium Resolution ◽  
Digital Elevation ◽  
Dense Point ◽  
Satellite Sensors ◽  
Close Range ◽  
Remote Sensing Techniques

<p><strong>Abstract.</strong> In this paper the use of different types of remote-sensing techniques for monitoring topographic changes of Alpine glaciers is presented and discussed. Close range photogrammetry based on Structure-from-Motion approach is adopted to process images recorded from ground-based and drone-based stations in order to output dense point clouds. These are then directly compared to detect local changes by mean of M3C2 algorithm, while digital elevation models are interpolated to find global ice thinning and retreat. Medium-resolution satellite imagery can be exploited to monitor the glacier evolution at lower resolution but including the development and collapse of large crevasses. A case study concerning the Forni Glacier in the Raethian Alps (Italy) is presented to demonstrate the feasibility of the proposed approach by adopting data sets collected from 2016 to 2018.</p>

scholarly journals UAV Photogrammetry and 3D Modelling of Complex Architecture for Maintenance Purposes: the Case Study of the Masonry Bridge on the Sele River, Italy

2020 ◽  
Author(s):  
Massimiliano Pepe ◽  
Domenica Costantino
Keyword(s):  
Structure From Motion ◽  
Point Cloud ◽  
3D Model ◽  
3D Models ◽  
3D Modelling ◽  
Complex Structures ◽  
Complex Architecture ◽  
3D Profile ◽  
Profile Reconstruction

The aim of this paper is to identify a suitable methodology to realize, in an easy and quick way, 3D models of complex structures. To achieve this aim, the first step is to build the 3D model of the scene under investigation using photogrammetric modelling. This task was carried out by the use of algorithms based on Structure from Motion (SfM) - Multi View Stereo (MVS) approaches and using camera-generated images supplied in the UAS (Unmanned Aerial system). Once built the 3D point cloud of the structure under investigation, the geometry of each element was reconstructed with 3D profile reconstruction using Rhinoceros software and a few plug-ins developed in this software. Indeed, this paper shows, through a case study of a masonry bridge of special architectural and historic value built in the middle of 1800s and located in the south of Italy, the potential of the method developed in order to manage a maintenance or restoration project.

scholarly journals A New Method for the Large-Scale Documentation of Pottery Sherds Through Simultaneous Multiple 3D Model Capture Using Structure from Motion: Phoenician Carinated-Shoulder Amphorae from Tell el-Burak (Lebanon) as a Case Study

2021 ◽  
Vol 7 (1) ◽  
pp. 256-272
Author(s):  
Fanet Göttlich ◽  
Aaron Schmitt ◽  
Andrea Kilian ◽  
Helen Gries ◽  
Kamal Badreshany
Keyword(s):  
Structure From Motion ◽  
Large Scale ◽  
3D Model ◽  
Low Cost ◽  
Cost Effective ◽  
New Method ◽  
Large Collection ◽  
Subsequent Research ◽  
Pottery Sherds

Abstract This paper presents a new rapid, low-cost method for the large-scale documentation of pottery sherds through simultaneous multiple 3D model capture using Structure from Motion (SfM). The method has great potential to enhance and replace time-consuming and expensive conventional approaches for pottery documentation, i.e., 2D photographs and drawing on paper with subsequent digitization of the drawings. To showcase the method’s effectiveness and applicability, a case study was developed in the context of an investigation of the Phoenician economy at the Lebanese site of Tell el-Burak, which is based on a large collection of amphora sherds. The same set of sherds were drawn by an experienced draftsperson and then documented through SfM using our new workflow to allow for a direct comparison. The results show that the new technique detailed here is accessible, more cost-effective, and allows for the documentation of ceramic data at a far-greater scale, while producing more consistent and reproducible results. We expect that these factors will enable excavators to greatly increase digital access to their material, which will significantly enhance its utility for subsequent research.

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