scholarly journals Automatic and Manual Fracture-Lineament Identification on Digital Surface Models as Methods for Collecting Fracture Data on Outcrops: Case Study on Fractured Granite Outcrops, Bangka

2020 ◽  
Vol 8 ◽  
Author(s):  
Muhammad Edo Marshal Nurshal ◽  
Muhammad Suwongso Sadewo ◽  
Arif Hidayat ◽  
Wildan Nur Hamzah ◽  
Benyamin Sapiie ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Aerial Images ◽  
Rapid Acquisition ◽  
Fracture Data ◽  
Granite Outcrops ◽  
Surface Models ◽  
Aerial Vehicle ◽  
Fracture Identification ◽  
The Hill

Three-dimensional outcrop models, or Digital Surface Models (DSMs), have proved their capacity in many geoscience studies. Along with the advantage in the rapid acquisition, DSMs are capable of creating virtual models of fractured outcrops to be interpreted for further analysis. This paper reports the DSM robustness by comparing the result of fracture-lineament measurement using DSMs and discusses the possible causes of error that might occur. The first method applied in this study is the scanline method to collect fracture data directly from outcrops, measuring more than 1,400 fracture data. The second method is applying fully automatic and manual fracture identification by optimizing hill-shaded DSMs. Two well-exposed granite outcrops in Bangka, Indonesia, are designed for the pilot area. Structure-from-Motion (SfM) photogrammetry is utilized to generate the DSMs, where a series of aerial images are captured using Unmanned Aerial Vehicle (UAV). The images are then processed into hill-shaded DSMs to be automatically analyzed following the algorithm in PCI Geomatics software and manually assessed. The textures of DSMs are also used in fracture identification through RGB filtering as the third method. The results show that the semiautomatic measurement using RGB-filtering texture has the closest pattern to the scanline data compared to the hill-shaded DSM method. The differences rely on several conditions, such as the geometry and texture of the outcrops. Eventually, methods of fracture identification using DSM are expected to be capable as options in preliminary fracture data collecting on outcrops, especially when the scanline is unable to be performed.

scholarly journals Detecting drainage pitfalls in open-pit mines and haul roads using UAV-photogrammetry

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 190-195
Author(s):  
Felipe Dille Benevenuti ◽  
Rodrigo De Lemos Peroni
Keyword(s):  
Three Dimensional ◽  
Open Pit ◽  
Road Maintenance ◽  
Open Pit Mines ◽  
Cycle Times ◽  
Course Material ◽  
Aerial Vehicle ◽  
Haul Road ◽  
Elevation Model

Open-pit mines generally have operational problems such as puddling and inappropriate water flow over haul roads, particularly if located in areas with high rainfall indices. These situations increase truck cycle times, promote rapid deterioration of haul-road wearing-course material, reduce productivity due to downtime and increase road maintenance. In addition, operational costs are raised as the frequency of truck maintenance and tire failures also increase. The use of a high-resolution three-dimensional elevation model, created based on Unmanned Aerial Vehicle (UAV) photogrammetry, has been shown to be an effective technique to detect anomalies in a fast and precise way. With the proposed approach, it is possible to diagnose haul-road conditions after rainfall or to anticipate the potential occurrence of such anomalies before they become a greater problem. This diagnosis can then be used to prioritize maintenance activities in open-pit mines. To describe the methodology, a case study is presented demonstrating and validating the results obtained.

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 Advanced 3D Photogrammetric Surface Reconstruction of Extensive Objects by UAV Camera Image Acquisition

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2815 ◽  
Author(s):  
Michele Calì ◽  
Rita Ambu
Keyword(s):  
Surface Reconstruction ◽  
Large Scale ◽  
Image Acquisition ◽  
Three Dimensional ◽  
Geometric Parameters ◽  
Reconstruction Accuracy ◽  
Camera Image ◽  
Aerial Vehicle ◽  
Euclidean Distances

This paper proposes a replicable methodology to enhance the accuracy of the photogrammetric reconstruction of large-scale objects based on the optimization of the procedures for Unmanned Aerial Vehicle (UAV) camera image acquisition. The relationships between the acquisition grid shapes, the acquisition grid geometric parameters (pitches, image rates, camera framing, flight heights), and the 3D photogrammetric surface reconstruction accuracy were studied. Ground Sampling Distance (GSD), the necessary number of photos to assure the desired overlapping, and the surface reconstruction accuracy were related to grid shapes, image rate, and camera framing at different flight heights. The established relationships allow to choose the best combination of grid shapes and acquisition grid geometric parameters to obtain the desired accuracy for the required GSD. This outcome was assessed by means of a case study related to the ancient arched brick Bridge of the Saracens in Adrano (Sicily, Italy). The reconstruction of the three-dimensional surfaces of this structure, obtained by the efficient Structure-From-Motion (SfM) algorithms of the commercial software Pix4Mapper, supported the study by validating it with experimental data. A comparison between the surface reconstruction with different acquisition grids at different flight heights and the measurements obtained with a 3D terrestrial laser and total station-theodolites allowed to evaluate the accuracy in terms of Euclidean distances.

scholarly journals Assessing Reef-Island Shoreline Change Using UAV-Derived Orthomosaics and Digital Surface Models

Drones ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 44 ◽  
Author(s):  
Meagan K. Lowe ◽  
Farrah Anis Fazliatul Adnan ◽  
Sarah M. Hamylton ◽  
Rafael C. Carvalho ◽  
Colin D. Woodroffe
Keyword(s):  
Solomon Islands ◽  
Three Dimensional ◽  
Shoreline Change ◽  
Multifaceted Approach ◽  
Ground Control Points ◽  
Surface Models ◽  
Aerial Vehicle ◽  
Reef Islands ◽  
Flight Parameters ◽  
Derived Data

This study presents an analysis of shoreline change on reef islands using unmanned aerial vehicle (UAV)-derived orthomosaics and digital surface models (DSMs) collected on Sipadan Island, Sabah, Malaysia, and Sasahura Ite Island, Isabel Province, Solomon Islands. The high resolution of UAV-derived orthomosaics enabled changes in the position of the base of beach to be detected with confidence. The accuracy of the UAV-derived DSMs was assessed against equivalent topographic profiles via root-mean-square error, and found to be <0.21 m in all but one case; this demonstrates the potential for using UAV-derived DSMs to interpret three-dimensional island beach morphology and detect patterns of geomorphic change. The correlation between planimetric and volumetric change along selected beach transects was also investigated and found to be variable, indicating that a multifaceted approach including both planimetric (two-dimensional) and volumetric (three-dimensional) metrics is of value when analysing reef-island change. However, interpretations of UAV-derived data must carefully consider errors associated with global positioning system (GPS) positioning, the distribution of ground control points, the chosen UAV flight parameters, and the data processing methodology. Further application of this technology has the potential to expand our understanding of reef-island morphodynamics and their vulnerability to sea-level rise and other stressors.

scholarly journals Simultaneous drainage events from supraglacial lakes on the southern Inylchek Glacier, Central Asia

2021 ◽  
pp. 1-12
Author(s):  
Naoki Sakurai ◽  
Chiyuki Narama ◽  
Mirlan Daiyrov ◽  
Muhammed Esenamanov ◽  
Zarylbek Usekov ◽  
...  
Keyword(s):  
Water Level ◽  
Drainage Water ◽  
Water Levels ◽  
Aerial Images ◽  
Supraglacial Lakes ◽  
Surface Models ◽  
Increase Rate ◽  
Aerial Vehicle ◽  
Water Level Variations ◽  
Gradient Line

Abstract To understand the mechanism of simultaneous drainage event related to supraglacial lakes on a debris-covered glacier, we investigated water-level variations of supraglacial lakes on the southern Inylchek Glacier in Kyrgyzstan. To examine these variations, we used daily aerial images for 2017–2019 from an uncrewed aerial vehicle that were converted to 15 cm-digital surface models and ortho-images. Our main results are as follows: (1) When one lake drained, the water levels of other lakes simultaneously increased, indicating that drainage water is shared with several lakes through a main englacial conduit. In one drainage event, a branched off englacial conduit clearly connected to a main englacial conduit. (2) Sometimes several lakes discharged simultaneously, indicating that several lakes had connected to a main englacial conduit that had opened. Such cases can cause larger-scale drainage than that from the opening of a branched off englacial conduit. (3) Simultaneous drainage occurred twice in the same year, each time through a different conduit, indicating that the main englacial conduit can be abandoned and reused. (4) In some lakes, the water level on the hydraulic gradient line increased gradually with nearly the same increase rate just before drainage. Such an increase may be an indicator of a possible simultaneous drainage event.

scholarly journals Influence of temporal baseline on the vertical absolute accuracies of TSX HS interferometric DSMs: Case Study on Berlin

2014 ◽  
Vol XL-7 ◽  
pp. 155-160
Author(s):  
U. G. Sefercik ◽  
U. Soergel
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Negative Influence ◽  
Absolute Accuracy ◽  
Surface Models ◽  
Sar Imagery ◽  
Image Pairs ◽  
Better Than ◽  
Aperture Radar

In recent years, interferometric sytnthetic aperture radar (InSAR) is one of the most preferred techniques to generate digital surface models (DSM) which are the three dimensional (3D) digital cartographic representations of earth surface including all terrain and non-terrain formations. Interferometric DSM generation using synthetic aperture radar (SAR) imagery is not an easy process and the vertical absolute accuracy of the final product depends on various parameters. In this study, we aimed to demonstrate the influence of temporal baseline between SAR image-pairs on the vertical absolute accuracy of high resolution interferometric DSMs. The application was realized covering 20 km<sup>2</sup> area in Berlin, Germany using 15 descending orbit high resolution spotlight (HS) TerraSAR-X (TSX) images. The suitable interferometric pairs were determined for DSM generation and two of them that have similar parameters except temporal baseline were selected regarding the purposes of the study. The master image was selected as same in the generation of both DSMs and the temporal baselines between this master image and slave images were 11 days (1 period) and 187 days (17 periods), respectively. TSX HS DSMs were generated with 2 m grid spacing and the vertical absolute accuracies were calculated based on the comparison with a reference DSM generated by radargrammetry. The analyses were realized for built-up and forest land classes separately. The results proved that longer temporal baseline has negative influence on the vertical absolute accuracies of TSX HS interferometric DSMs. The first DSM which has the shortest temporal baseline, possible for TSX sensing is better than the second one as approx. 1.5 m both for built-up and forest areas.

scholarly journals Accuracy of Digital Surface Models derived from archival aerial photographs. Case study for the Czech Republic.

2017 ◽  
Vol 16 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Jan Pacina ◽  
Jan Popelka
Keyword(s):  
Czech Republic ◽  
Aerial Images ◽  
Aerial Photographs ◽  
Change Analysis ◽  
The Czech Republic ◽  
Accuracy Test ◽  
Surface Models ◽  
Images Processing

The archival aerial photographs are widely used for landscape change analysis, settlement identification or georelief reconstructions. The large archive of old aerial photographs is available for the whole Czech Republic and these data are often used by scientists, historians, students, etc. The quality of the datasets (orthophoto, digital surface models) resulting from archival aerial images processing is crucial for the ongoing analyses. The accuracy test of digital surface models derived from archival aerial images origintaing from 1938 and 1953 is presented within this paper. These two timelines were chosen because they preserve the landscape structure in the begining of the heavy indudstrialization of the Czech Republic.

scholarly journals UTILIZATION OF LARGE SCALE SURFACE MODELS FOR DETAILED VISIBILITY ANALYSES

2017 ◽  
Vol XLII-2/W8 ◽  
pp. 53-58
Author(s):  
J. Caha ◽  
M. Kačmařík
Keyword(s):  
Large Scale ◽  
Local Level ◽  
Surface Model ◽  
Target Area ◽  
Large Scale Data ◽  
Viewshed Analysis ◽  
Surface Models ◽  
Aerial Vehicle ◽  
Scale Surface

This article demonstrates utilization of large scale surface models with small spatial resolution and high accuracy, acquired from Unmanned Aerial Vehicle scanning, for visibility analyses. The importance of large scale data for visibility analyses on the local scale, where the detail of the surface model is the most defining factor, is described. The focus is not only the classic Boolean visibility, that is usually determined within GIS, but also on so called extended viewsheds that aims to provide more information about visibility. The case study with examples of visibility analyses was performed on river Opava, near the Ostrava city (Czech Republic). The multiple Boolean viewshed analysis and global horizon viewshed were calculated to determine most prominent features and visibility barriers of the surface. Besides that, the extended viewshed showing angle difference above the local horizon, which describes angular height of the target area above the barrier, is shown. The case study proved that large scale models are appropriate data source for visibility analyses on local level. The discussion summarizes possible future applications and further development directions of visibility analyses.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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