Identifying and mapping potentially adverse discontinuities in underground excavations using thermal and multispectral UAV imagery

Turner, R. M.; MacLaughlin, Mary; Iverson, S.R.

doi:10.1016/j.enggeo.2019.105470

Cited by 28 publications

(18 citation statements)

References 7 publications

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“…Moreover, the increment of RPAS datasets is additionally broadening the potential application of such an approach [52,53]. Although these systems were initially implemented to acquire data in extensive outdoor environments, there are now many recent studies that describe their applicability in indoor spaces [54,55], even in dark caves [56]; in this last case, proposed solutions are mainly employed for the survey of small portions of the natural cave [57] and not for extensive surveys.…”

Section: Introductionmentioning

confidence: 99%

Survey Solutions for 3D Acquisition and Representation of Artificial and Natural Caves

et al. 2021

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A three-dimensional survey of natural caves is often a difficult task due to the roughness of the investigated area and the problems of accessibility. Traditional adopted techniques allow a simplified acquisition of the topography of caves characterized by an oversimplification of the geometry. Nowadays, the advent of LiDAR and Structure from Motion applications eased three-dimensional surveys in different environments. In this paper, we present a comparison between other three-dimensional survey systems, namely a Terrestrial Laser Scanner, a SLAM-based portable instrument, and a commercial photo camera, to test their possible deployment in natural caves survey. We presented a comparative test carried out in a tunnel stretch to calibrate the instrumentation on a benchmark site. The choice of the site is motivated by its regular geometry and easy accessibility. According to the result obtained in the calibration site, we presented a methodology, based on the Structure from Motion approach that resulted in the best compromise among accuracy, feasibility, and cost-effectiveness, that could be adopted for the three-dimensional survey of complex natural caves using a sequence of images and the structure from motion algorithm. The methods consider two different approaches to obtain a low resolution complete three-dimensional model of the cave and ultra-detailed models of most peculiar cave morphological elements. The proposed system was tested in the Gazzano Cave (Piemonte region, Northwestern Italy). The obtained result is a three-dimensional model of the cave at low resolution due to the site’s extension and the remarkable amount of data. Additionally, a peculiar speleothem, i.e., a stalagmite, in the cave was surveyed at high resolution to test the proposed high-resolution approach on a single object. The benchmark and the cave trials allowed a better definition of the instrumentation choice for underground surveys regarding accuracy and feasibility.

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Section: Introductionmentioning

confidence: 99%

Survey Solutions for 3D Acquisition and Representation of Artificial and Natural Caves

et al. 2021

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“…A number of studies have managed to demonstrate successful use of drones for reallife applications within confined spaces [12][13][14][15][16][17][18][19][20][21]. These studies have conducted missions that require localisation of the drone in the confined spaces for the purpose of mapping or inspection.…”

Section: Research Background 21 Examples Of Drone Missions In Confined Spacesmentioning

confidence: 99%

“…However, the study was not extended to mission cases with no/limited light conditions within the sewer system. Anderson et al [16] built a drone called the "Smellicopter" as an odour-finding robot based on the Crazyflie 2.0. The drone was equipped with a less than 3cm 2 custom electroantennogram (EAG) circuit that has a biological antenna.…”

Section: Research Background 21 Examples Of Drone Missions In Confined Spacesmentioning

confidence: 99%

Drone-Assisted Confined Space Inspection and Stockpile Volume Estimation

et al. 2021

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The accuracy of stockpile estimations is of immense criticality to process optimisation and overall financial decision making within manufacturing operations. Despite well-established correlations between inventory management and profitability, safe deployment of stockpile measurement and inspection activities remain challenging and labour-intensive. This is perhaps owing to a combination of size, shape irregularity as well as the health hazards of cement manufacturing raw materials and products. Through a combination of simulations and real-life assessment within a fully integrated cement plant, this study explores the potential of drones to safely enhance the accuracy of stockpile volume estimations. Different types of LiDAR sensors in combination with different flight trajectory options were fully assessed through simulation whilst mapping representative stockpiles placed in both open and fully confined areas. During the real-life assessment, a drone was equipped with GPS for localisation, in addition to a 1D LiDAR and a barometer for stockpile height estimation. The usefulness of the proposed approach was established based on mapping of a pile with unknown volume in an open area, as well as a pile with known volume within a semi-confined area. Visual inspection of the generated stockpile surface showed strong correlations with the actual pile within the open area, and the volume of the pile in the semi-confined area was accurately measured. Finally, a comparative analysis of cost and complexity of the proposed solution to several existing initiatives revealed its proficiency as a low-cost robotic system within confined spaces whereby visibility, air quality, humidity, and high temperature are unfavourable.

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“…Raeva et al (2019) carried out unmanned flights with a fixed-wing platform with two different sensors -multispectral and thermal in order to examine two main crops cultivated area. Turner et al (2020) investigated geological discontinuities in hard rock masses using UAV-mounted thermal and multispectral cameras. Matese and Di Gennaro (2018) described the implementation of a multisensor UAV system capable of flying with three sensors simultaneously to present performances in the characterization of spatial variability in terms of vegetative vigor, water stress and missing plant detection.…”

Section: Introductionmentioning

confidence: 99%

Photogrammetric analysis of multispectral and thermal close-range images

Akçay

2021

Mersin Photogrammetry Journal

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PhotogrammetryRemote sensing Multispectral images Thermal images Close-range Sensors capable of multispectral and thermal imaging beyond visible bands offer many analysis possibilities for environmental monitoring. Different sensor images constitute an important source of information especially in the fields of agriculture, forestry, geology and energy. Photogrammetric studies have been affected by this development in recent years and have been used in the production of multispectral and thermal models besides the RGB model. However, due to geometric and radiometric resolution differences, it is difficult to combine or evaluate models produced from different types of sensors. In this study, the three-dimensional test field images obtained with RGB, multispectral and thermal sensors were oriented and modeled photogrammetrically. The accuracies of the control points on the produced models were compared and discussed. When the results are examined, control point accuracy was obtained as almost similar as in the RGB model after the orientation based on automatic feature matching. Automatic feature detection and matching in thermal images were not robustly produced due to low geometric resolution. For this reason, manual measurements were performed in thermal images, and the photogrammetric orientation and adjustment process was done accordingly. The fused evaluation approach considering RGB, multispectral and thermal images in one photogrammetric model was also implemented and discussed.

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Identifying and mapping potentially adverse discontinuities in underground excavations using thermal and multispectral UAV imagery

Cited by 28 publications

References 7 publications

Survey Solutions for 3D Acquisition and Representation of Artificial and Natural Caves

Survey Solutions for 3D Acquisition and Representation of Artificial and Natural Caves

Drone-Assisted Confined Space Inspection and Stockpile Volume Estimation

Photogrammetric analysis of multispectral and thermal close-range images

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