Accuracy Assessment of 3D Photogrammetric Models from an Unmanned Aerial Vehicle

Barba, Salvatore; Barbarella, Maurizio; Benedetto, Alessandro Di; Fiani, Margherita; Gujski, Lucas Matias; Limongiello, Marco

doi:10.3390/drones3040079

Cited by 66 publications

(52 citation statements)

References 37 publications

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“…Hlotov V. M., Tserklevych A. L., Kolisnichenko V. B., Prokharchuk O. V., Galetsky V. and others [Vovk, et al, 2015;Galetsky, 2012]. The similar to our researches methodology in their works are described by foreign scientists P. Barry, R. Coakley, J. Goncalves, R. Henrikues, Chris Cryderman, S. Bill Mah, Aaron Shufletoski and others [Cryderman, et al, 2014;Barba, 2019;Agüera-Vega, et al, 2017;James, et al, 2017;Goncalves, & Henrikues, 2015;Barry, & Coakley, 2013].…”

Section: Introductionsupporting

confidence: 60%

Geodesy, Cartography and Aerial Photography

Chetverikov¹,

Babiy²,

Protsyk³

et al. 2019

ISTCGCAP

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The aim of the work is to estimate the error of the ortho rectification of aerial images obtained by unmanned aerial vehicle for a mountain site in the village Shidnytsya with the help of additional grid of points obtained by GNSS-survey. The task is to analyse the difference between the heights of the points obtained using two methods: using the map of heights from the UAV survey and using data of GNSS-survey and then to estimate the difference between the real coordinates of the ground control points with their coordinates on the orthophoto plan. The method. It is proposed to use the method of ortho rectification of aerial images obtained by UAV on mountainous terrain for determination of the real value of height error. A local test site with size approximately 70´60 meters was created on the hill in the village Shidnytsya, The site is part of terrain covered by a general aerial survey of the village. On this site an additional GNSS-survey was implemented and a grid of points with measured coordinates was generated with step one meter. Processing of the obtained ortho image height map based on the data of the aerial survey of the entire Shidnytsya and the results of GNSS-survey was realized in the software of ArcGIS. Layer of points of the local test site was overlaid on the aerial image and then this data were compared with the coordinates of the same points obtained from the map of heights. Results. Comparing the height values of 87 points on the test site to the height values of the same points obtained from the map of heights created on the basis of aerial survey implemented by unmanned aerial vehicle, it was determined that the height values of the points are not very different. The root mean square error is 0.39 m. Scientific novelty. The method of comparing the values of terrain point heights obtained using different technologies for determination of the value of the error of ortho rectification of aerial images obtained by UAV on mountainous local site near the village Shidnytsya is proposed. Practical significance. The obtained results of error values of aerial images ortho rectification show that ortho rectification of aerial images of some mountainous areas obtained using the UAV is in the zone of tolerance.

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Section: Introductionsupporting

confidence: 60%

Geodesy, Cartography and Aerial Photography

Chetverikov¹,

Babiy²,

Protsyk³

et al. 2019

ISTCGCAP

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“…Therefore, the aim and novelty of this research is to evaluate the results achievable with the DJI-P4RTK drone and an Agisoft Metashape data processing in the field of building and façade modeling, instead of land mapping, like Forlani et al [32], Kalacska et al [38], Barba et al [39], and Štroner et al [37], through a rigorous set up of the assessment test. In this work, we designed the image acquisition acquiring also oblique images in order to avoid issues that are related to the estimation of a wrong focal length [32,33].…”

Section: Introductionmentioning

confidence: 99%

Quality Assessment of Photogrammetric Models for Façade and Building Reconstruction Using DJI Phantom 4 RTK

et al. 2020

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Aerial photogrammetry by Unmanned Aerial Vehicles (UAVs) is a widespread method to perform mapping tasks with high-resolution to reconstruct three-dimensional (3D) building and façade models. However, the survey of Ground Control Points (GCPs) represents a time-consuming task, while the use of Real-Time Kinematic (RTK) drones allows for one to collect camera locations with an accuracy of a few centimeters. DJI Phantom 4 RTK (DJI-P4RTK) combines this with the possibility to acquire oblique images in stationary conditions and it currently represents a versatile drone widely used from professional users together with commercial Structure-from-Motion software, such as Agisoft Metashape. In this work, we analyze the architectural application of this drone to the photogrammetric modeling of a building with particular regard to metric survey specifications for cultural heritage for 1:20, 1:50, 1:100, and 1:200 scales. In particular, we designed an accuracy assessment test signalizing 109 points, surveying them with total station and adjusting the measurements through a network approach in order to achieve millimeter-level accuracy. Image datasets with a designed Ground Sample Distance (GSD) of 2 mm were acquired in Network RTK (NRTK) and RTK modes in manual piloting and processed both as single façades (S–F) and as an overall block (4–F). Subsequently, we compared the results of photogrammetric models generated in Agisoft Metashape to the Signalized Point (SP) coordinates. The results highlight the importance of processing an overall photogrammetric block, especially whenever part of camera locations exhibited a poorer accuracy due to multipath effects. No significant differences were found between the results of network real-time kinematic (NRTK) and real-time kinematic (RTK) datasets. Horizontal residuals were generally comparable to GNSS accuracy in NRTK/RTK mode, while vertical residuals were found to be affected by an offset of about 5 cm. We introduced an external GCP or used one SP per façade as GCP, assuming a poorer camera location accuracy at the same time, in order to fix this issue and comply with metric survey specifications for the widest architectural scale range. Finally, both S–F and 4–F projects satisfied the metric survey requirements of a scale of 1:50 in at least one of the approaches tested.

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“…The reprojection error is the geometric error corresponding to the Euclidean image distance between a projected 3D point and the marked points based off the GCPs locations [93], and according to [54] it is the Euclidean distance between a manually or automatically measured image point and the back-projected position of the corresponding 3D point in the same image. Other studies highlighted the importance of these results [42] in the photogrammetric accuracy. The data obtained in Surveys A (0.416 px) and B (0.408 px) are similar.…”

Section: Discussionmentioning

confidence: 99%

“…Focusing on the reliability of this technique, another research work calculated 95% accuracy of UAV photogrammetry against classic topography measurements [41]. The model accuracy through UAV photogrammetry depends of certain parameters [42]: The angle of homologous rays in different photographs [43], the number of control points-directly proportional to model accuracy [44]-the flight height [45] and the angle of photogrammetry shots [46], among others.…”

Section: Related Workmentioning

confidence: 99%

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

et al. 2020

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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.

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Accuracy Assessment of 3D Photogrammetric Models from an Unmanned Aerial Vehicle

Cited by 66 publications

References 37 publications

Geodesy, Cartography and Aerial Photography

Geodesy, Cartography and Aerial Photography

Quality Assessment of Photogrammetric Models for Façade and Building Reconstruction Using DJI Phantom 4 RTK

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

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