Accurate measurement with photogrammetry at large sites

Sapirstein, Philip

doi:10.1016/j.jas.2016.01.002

Cited by 120 publications

(101 citation statements)

References 28 publications

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“…UAVs and structure-from-motion (SfM) photogrammetric software have become go-to tools for monitoring hazardous locations such as landslides [6][7][8][9][10][11][12] and subsidence/sinkholes [13][14][15]. These technologies have also been widely adopted in coastal erosion [16][17][18], marine science [19][20][21], both marine and terrestrial ecology [22][23][24][25][26][27], archaeology [28][29][30][31][32][33][34][35], and civil engineering [36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Measuring Change Using Quantitative Differencing of Repeat Structure-From-Motion Photogrammetry: The Effect of Storms on Coastal Boulder Deposits

Nagle-McNaughton

Cox

2019

Remote Sensing

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Repeat photogrammetry is increasingly the go-too tool for long-term geomorphic monitoring, but quantifying the differences between structure-from-motion (SfM) models is a developing field. Volumetric differencing software (such as the open-source package CloudCompare) provides an efficient mechanism for quantifying change in landscapes. In this case study, we apply this methodology to coastal boulder deposits on Inishmore, Ireland. Storm waves are known to move these rocks, but boulder transportation and evolution of the deposits are not well documented. We used two disparate SfM data sets for this analysis. The first model was built from imagery captured in 2015 using a GoPro Hero 3+ camera (fisheye lens) and the second used 2017 imagery from a DJI FC300X camera (standard digital single-lens reflex (DSLR) camera); and we used CloudCompare to measure the differences between them. This study produced two noteworthy findings: First, volumetric differencing reveals that short-term changes in boulder deposits can be larger than expected, and that frequent monitoring can reveal not only the scale but the complexities of boulder transport in this setting. This is a valuable addition to our growing understanding of coastal boulder deposits. Second, SfM models generated by different imaging hardware can be successfully compared at sub-decimeter resolution, even when one of the camera systems has substantial lens distortion. This means that older image sets, which might not otherwise be considered of appropriate quality for co-analysis with more recent data, should not be ignored as data sources in long-term monitoring studies.Despite these improvements in protocols for data collection and analysis, quantifying change via repeat photogrammetry remains a challenge, generally requiring manipulation of digital terrain models (DTMs) using Geographic Information Systems (GIS) [45,46]. But recent innovations in 3D differencing software, as implemented in the open-source package CloudCompare (www.danielgm.net/cc/) enable rapid, objective, and replicable quantitative differencing [47]. CloudCompare is a cross-platform 3D point cloud and mesh processing package, which provides a suite of features for direct comparison of dense point clouds (>10 million points) and meshes on standard consumer computer hardware [48,49]. Accessibility and ease of use make CloudCompare an attractive tool, and it is applied increasingly in a variety of fields, including mapping [50,51], archaeology [52,53], and geomorphology [54][55][56][57].Another issue relevant to long term monitoring studies is how to deal with repeat imagery captured using different kinds of hardware, with different resolutions and/or distortion levels. The ultra-wide-angle (fisheye) lenses mounted on the popular consumer camera brand GoPro capture a~120 • field of view, but have barrel distortion due to their short focal length. Despite their limitations, GoPro cameras are popular tools for acquiring UAV imagery [24,31,[58][59][60], they are relatively inexpensive, are light enou...

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Section: Introductionmentioning

confidence: 99%

Measuring Change Using Quantitative Differencing of Repeat Structure-From-Motion Photogrammetry: The Effect of Storms on Coastal Boulder Deposits

Nagle-McNaughton

Cox

2019

Remote Sensing

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“…Since TS measurements and traditional images are already part of the normal archaeological surveying, the only addition has been the photogrammetric set. Images have been taken with an uncalibrated camera (Nikon D90, 12.3 megapixel equipped with a Sigma lens 20mm F1.8 EX DG ASP RF); The camera has not been calibrated since past comparisons between not calibrated cameras and more accurate instruments demonstrated that accuracy needed for this kind of applications is still preserved (Barazzetti and Scaioni, 2014;Chandler et al, 2005;Green et al, 2014;James and Robson, 2012;Sapirstein, 2016;Wackrow et al, 2007). Photogrammetric blocks have been set both for every single SUs and open areas; needed images were included into a range of 15 and 70.…”

Section: On-field Methodologymentioning

confidence: 99%

Object-Oriented Approach for 3d Archaeological Documentation

Valente

Brumana

Oreni

et al. 2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Documentation on archaeological fieldworks needs to be accurate and time-effective. Many features unveiled during excavations can be recorded just once, since the archaeological workflow physically removes most of the stratigraphic elements. Some of them have peculiar characteristics which make them hardly recognizable as objects and prevent a full 3D documentation. The paper presents a suitable feature-based method to carry on archaeological documentation with a three-dimensional approach, tested on the archaeological site of S. Calocero in Albenga (Italy). The method is based on one hand on the use of structure from motion techniques for on-site recording and 3D Modelling to represent the three-dimensional complexity of stratigraphy. The entire documentation workflow is carried out through digital tools, assuring better accuracy and interoperability. Outputs can be used in GIS to perform spatial analysis; moreover, a more effective dissemination of fieldworks results can be assured with the spreading of datasets and other information through web-services.

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“…The process of photogrammetry requires the use of a series of ground control points (GCPs) in order to assist in processing and allow georectification of the model (Sapirstein, ). Early attempts at terrestrial thermography often resulted in poor or misaligned photogrammetric models, due to little thermal variation in each image, which can cause confusion in photogrammetry software.…”

Section: Case Study – Zagora Androsmentioning

confidence: 99%

“…Thermal photography is often performed after dark, so that infrared radiation from the sun does not affect the results. When combined with the technique of photogrammetry (Bendea, Chiabrando, Giulio Tonolo, & Marenchino, ;De Reu, De Clercq, Sergant, Deconynck, & Laloo, ; De Reu, Plets, et al, ; Sapirstein, ; Thomas, 2018; Thomas & Kennedy, ; Verhoeven, ; Verhoeven, Taelman, & Vermeulen, ) large thermal orthophotographs can be produced, placing any thermal anomalies within a wider context. Orthophotographs produced with thermal images can be compared to a ‘control’ created with regular RGB (red–green–blue) photography, in order to determine if any thermal variations are caused by subsurface remains or whether they are a result of natural processes, like bioturbation, or manmade, like car tyre tracks.…”

Section: Introductionmentioning

confidence: 99%

High resolution terrestrial thermography of archaeological sites

Thomas

Williams²

2019

Archaeological Prospection

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Thermal infrared imaging, or thermography, is the remote sensing technique of detecting variations in ground temperature caused by exposed or subsurface archaeological remains either absorbing or radiating heat. Despite its conception in the 1970s, the practice has to date been rarely utilized, as a result of the high cost of the technology and the complex interplay of environmental variables. However, recent studies have demonstrated the effectiveness of the technique, especially when combining modern thermal cameras with unmanned aerial vehicles (UAV). Yet these papers often focus on mid-to high-altitude flights, where the technique is only effective at detecting larger thermal anomalies. This article presents a new method for terrestrial thermography, developed for the Zagora Infrared Photogrammetry Project (The University of Sydney and the Australian Archaeological Institute at Athens).The project undertook a six week thermal investigation of the Early Iron Age site of Zagora and the surrounding hinterland utilizing the newest commercial thermal cameras and UAVs. The method of terrestrial thermography involves using photographic poles and photogrammetry to create high-resolution thermal orthophotographs, which allow the detection of smaller thermal anomalies, providing significantly more detail than aerial thermography. Several features were discovered using this method, including a possible kiln, which would be the first ever identified at the site.

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Accurate measurement with photogrammetry at large sites

Cited by 120 publications

References 28 publications

Measuring Change Using Quantitative Differencing of Repeat Structure-From-Motion Photogrammetry: The Effect of Storms on Coastal Boulder Deposits

Measuring Change Using Quantitative Differencing of Repeat Structure-From-Motion Photogrammetry: The Effect of Storms on Coastal Boulder Deposits

Object-Oriented Approach for 3d Archaeological Documentation

High resolution terrestrial thermography of archaeological sites

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