Thin-bedded reservoir analogs in an ancient delta using terrestrial laser scanner and high-resolution ground-based hyperspectral cameras

2016 ◽  
Vol 342 ◽  
pp. 154-164 ◽  
Author(s):  
Casey J. Snyder ◽  
Shuhab D. Khan ◽  
Janok P. Bhattacharya ◽  
Craig Glennie ◽  
Darsel Seepersad
2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Federico Preti ◽  
Paolo Tarolli ◽  
Andrea Dani ◽  
Simone Calligaro ◽  
Massimo Prosdocimi

The soil erosion in the vineyards is a critical issue that could affect their productivity, but also, when the cultivation is organized in terraces, increase the risk due to derived slope failure processes. If terraces are not correctly designed or maintained, a progressively increasing of gully erosion affects the structure of the walls. The results of this process is the increasing of connectivity and runoff. In order to overcome such issues it is really important to recognize in detail all the surface drainage paths, thus providing a basis upon which develop a suitable drainage system or provide structural measures for the soil erosion risk mitigation. In the last few years, the airborne LiDAR technology led to a dramatic increase in terrain information. Airborne LiDAR and Terrestrial Laser Scanner derived high-resolution Digital Terrain Models (DTMs) have opened avenues for hydrologic and geomorphologic studies (Tarolli et al., 2009). In general, all the main surface process signatures are correctly recognized using a DTM with cell sizes of 1 m. However sub-meter grid sizes may be more suitable in those situations where the analysis of micro topography related to micro changes is critical for slope failures risk assessment or for the design of detailed drainage flow paths. The Terrestrial Laser Scanner (TLS) has been proven to be an useful tool for such detailed field survey. In this work, we test the effectiveness of high resolution topography derived by airborne LiDAR and TLS for the recognition of areas subject to soil erosion risk in a typical terraced vineyard landscape of “Chianti Classico” (Tuscany, Italy). The algorithm proposed by Tarolli et al. (2013), for the automatic recognition of anthropic feature induced flow direction changes, has been tested. The results underline the effectiveness of LiDAR and TLS data in the analysis of soil erosion signatures in vineyards, and indicate the high resolution topography as a useful tool to improve the land use management of such areas. The stability conditions have been analyzed under the influence of the measured geometry alterations of the wall structure.


2020 ◽  
Author(s):  
Giuseppe Casula ◽  
Silvana Fais ◽  
Francesco Cuccuru ◽  
Maria Giovanna Bianchi ◽  
Paola Ligas

<p>A multi-technique high resolution 3D modelling is described here aimed at the investigation of the state of conservation of carbonate columns of the 1000 BC ancient church of Buon Camino located in the homonymous district of the town of Cagliari (Italy).</p><p>The integrated application of different Non-Destructive Testing (NDT) diagnostic methods is of paramount importance to locate damaged parts of the building material of artefacts of historical buildings and to plan their restoration.</p><p>In this study a multi-step procedure was applied starting with a high resolution 3D modelling performed with the aid of Structure from Motion (SfM) Photogrammetry and Terrestrial Laser Scanner (TLS) methodologies. For this delicate task we operated simultaneously a Nikon D-5300 digital Reflex 24.2 Mega pixel Camera and a Leica HDS-6200 Terrestrial Laser Scanner. Subsequently, starting from the information detected with the above methods deeper material diagnostics was performed by means of high resolution 3D ultrasonic tomography aimed at the capillary definition of the elastic properties in the inner parts of the building materials. Measurements of longitudinal wave velocity from ultrasonic data were performed using the transmission method, namely two piezoelectric transducers coupled on the opposite sides of the investigated columns. The ultrasonic data acquisition was planned designing an optimal survey and providing a very good spatial coverage of the investigated columns. The columns were then criss-crossed by a large number of ray paths forming a dense 3D net. The SIRT (Simultaneous Iterative Reconstruction Tomography) algorithm was used to produce the 3D rendering of the velocity distribution inside the investigated columns. With this method the damaged parts were located and it was possible to distinguish them from the unaltered areas. The information on the superficial material conditions obtained by SfM and TLS techniques were compared and integrated with the information of the inner materials obtained by 3D ultrasonic tomography.</p><p>The results of the above non invasive geophysical techniques have been interpreted in the light of the different textural and petrophysical features of the study carbonate building materials. The study of the main textural features, such as the relationship between bioclasts, carbonate matrix, or that of the cement and petrophysical characteristics such as the nature and distribution of porosity were found to be of fundamental importance in the interpretation of the geophysical data (e.g. TLS reflectance and longitudinal acoustic wave propagation). Therefore a detailed analysis of the textures and pore microstructure were carried out from petrographic thin-sections in Optical and Scanning Electron Microscopy (OM/SEM). The final result of our multi-step-technique integrated methodology is a sophisticated 3D model with a high resolution 3D image representing the internal and external parts of the investigated columns in order to account for their static load resistance and possibly plan their conservation and restoration. The described procedure can also be applied to other cases in which a diagnosis is needed of the state of conservation of the variously shaped, layered-stones and composed artefacts typical of ancient historical buildings.</p><p>Key words: 3D Modelling, 3D Ultrasonic Tomography, Terrestrial Laser Scanner, SfM Photogrammetry, Non-Destructive Testing, Diagnostic, Ancient Columns, Stones</p>


Author(s):  
Cecilia Maria Bolognesi ◽  
Fausta Fiorillo

The integration of close-range photogrammetry and terrestrial laser scanner enables reality-based modeling procedures that can help BIM modeling for existing buildings. The restitution of virtual models from high-resolution surveys is a complex process that requires much expertise. It incorporates concepts of resolution, accuracy, and precision in the acquisition phase; filtering, registration, and decimation for point cloud elaboration; and meshing, texturing, simplification, segmentation, and feature extraction in the final modeling stage. The previous steps are the same whether the ultimate goal is a classic 2D representation or a 3D one. For BIM modeling, the job becomes challenging because the necessary simplification of the model cannot be automatized and apparently collides with the high resolution and fidelity of original surveyed data. This chapter presents the process of surveying and 3D modeling of the Ghesc village, following the whole path from data acquisition to BIM modeling, discussing strengths and weakness, issues, and recent solutions for restoration interventions.


Author(s):  
Nikolay Lugovoy ◽  
Nikolay Lugovoy ◽  
Askar Ilyasov ◽  
Askar Ilyasov ◽  
Elena Pronina ◽  
...  

The paper describes application of the terrestrial laser scanner for investigation of coastal dynamics of the Svetlogorskaya Bay, Baltic Sea. Methods of investigation and results of surveys repeated over the two consecutive years for quantification of coastal erosion and slope processes within the coastal zone are presented.


2020 ◽  
Author(s):  
Collin Megee ◽  
◽  
Michael O'Neal ◽  
Joseph Clemens ◽  
Erica McMaster ◽  
...  

2021 ◽  
Vol 13 (13) ◽  
pp. 2494
Author(s):  
Gaël Kermarrec ◽  
Niklas Schild ◽  
Jan Hartmann

T-splines have recently been introduced to represent objects of arbitrary shapes using a smaller number of control points than the conventional non-uniform rational B-splines (NURBS) or B-spline representatizons in computer-aided design, computer graphics and reverse engineering. They are flexible in representing complex surface shapes and economic in terms of parameters as they enable local refinement. This property is a great advantage when dense, scattered and noisy point clouds are approximated using least squares fitting, such as those from a terrestrial laser scanner (TLS). Unfortunately, when it comes to assessing the goodness of fit of the surface approximation with a real dataset, only a noisy point cloud can be approximated: (i) a low root mean squared error (RMSE) can be linked with an overfitting, i.e., a fitting of the noise, and should be correspondingly avoided, and (ii) a high RMSE is synonymous with a lack of details. To address the challenge of judging the approximation, the reference surface should be entirely known: this can be solved by printing a mathematically defined T-splines reference surface in three dimensions (3D) and modeling the artefacts induced by the 3D printing. Once scanned under different configurations, it is possible to assess the goodness of fit of the approximation for a noisy and potentially gappy point cloud and compare it with the traditional but less flexible NURBS. The advantages of T-splines local refinement open the door for further applications within a geodetic context such as rigorous statistical testing of deformation. Two different scans from a slightly deformed object were approximated; we found that more than 40% of the computational time could be saved without affecting the goodness of fit of the surface approximation by using the same mesh for the two epochs.


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