Reconstruction of extreme topography from UAV structure from motion photogrammetry

Agüera-Vega, Francisco; Ramírez, Fernando Carvajal; Martínez-Carricondo, Patricio; López, Julián Sánchez-Hermosilla; Mesas‐Carrascosa, Francisco Javier; García-Ferrer, Alfonso; Porras, Fernando Pérez

doi:10.1016/j.measurement.2018.02.062

Cited by 87 publications

(58 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Far-range remote sensing could be a solution in the future, but for now, satellite and aerial data do not enable to observe subtle changes because their resolution is not sufficient and because they generally capture only the cliff top [4]. Thus, considering their high spatial and temporal resolution, their low cost and their operational flexibility, near-range remote sensing methods (land-based or using UAVs) are increasingly used for the cliff face monitoring [4][5][6][7][8].…”

mentioning

confidence: 99%

See 1 more Smart Citation

UAV survey of a coastal cliff face – Selection of the best imaging angle

et al. 2019

View full text Add to dashboard Cite

UAVs are relevant for monitoring cliff faces. In this study, several flights are performed with various imaging angles (nadir, 20°, 30° and 40° off-nadir) to assess the impact of the imaging angle on the 3D cliff face reconstruction. Occlusions issues arising with sub-vertical cliffs make nadir surveys nearly irrelevant. The results obtained with 20°, 30° and 40° off-nadir imaging angles are satisfactory regarding texture restitution and accuracy with respectively 5.5 cm, 5.9 cm and 4.9 cm of error, higher tilting angles yielding better reconstructions on sub-vertical or overhanging parts of the cliff. This article also investigates other parameters affecting tiepoint detection on the cliff face, as the effective overlap, the UAV-cliff face distance and the cliff face illumination. Guidelines are provided for UAV survey parameterization, aiming at capturing the whole cliff face with a good trade-off between distance to the cliff, flight height and spatial resolution of the photographs. Highlights Impact of the UAV camera tilting angle on the 3D cliff face reconstruction  Because of occlusions, irrelevance of nadir pointing camera for sub-vertical cliffs  Satisfying accuracy and texture for both 20°, 30° and 40° off-nadir imaging angles  Other parameters impacting tiepoint detection in the reconstruction process

show abstract

mentioning

confidence: 99%

“…In [16], photographs from three flight paths with various aiming direction (horizontal, 45° oblique and vertical) are combined, mainly in order to limit distortions. In [6], images are taken with horizontal axis orientation and with the axis tilted 45° downward. For forestry applications, UAV surveys are usually performed with a tilt angle of 45° [19].…”

mentioning

confidence: 99%

UAV survey of a coastal cliff face – Selection of the best imaging angle

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Currently, the most commonly used remote sensing methods for such a fine-scale 3D mapping comprise terrestrial laser scanning (TLS)-i.e., terrestrial lidar [5,6]-and close-range photogrammetry based on image matching by structure from motion, typically based on unmanned aerial vehicles as the sensor platforms (UAV-SfM) [7][8][9][10]. The main benefit of the technologies is in fast data acquisition and high accuracy-several millimeters for TLS [11][12][13] and several centimeters for UAV-SfM [14][15][16]. The achievable ultra-high spatial resolution provides means for analysing structural properties of rock outcrops [17,18], landslide dynamics [19], relative age of landforms [20], soil erosion [21], biomass [22], 3D city modelling [23] or archaeology [24].…”

Section: Introductionmentioning

confidence: 99%

“…Several studies demonstrated the use of UAV-SfM for mapping rugged terrains such as alpine mountains [32], coastal cliffs [14], or volcanos [37]. However, these studies put the focus on validation Deglaciated alpine landscape with landforms of different size, shape and verticality ( Figure 2) pose a serious challenge for mapping with high sampling density and homogenous data coverage.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Combined Use of Terrestrial Laser Scanning and UAV Photogrammetry in Mapping Alpine Terrain

et al. 2019

View full text Add to dashboard Cite

Airborne and terrestrial laser scanning and close-range photogrammetry are frequently used for very high-resolution mapping of land surface. These techniques require a good strategy of mapping to provide full visibility of all areas otherwise the resulting data will contain areas with no data (data shadows). Especially, deglaciated rugged alpine terrain with abundant large boulders, vertical rock faces and polished roche-moutones surfaces complicated by poor accessibility for terrestrial mapping are still a challenge. In this paper, we present a novel methodological approach based on a combined use of terrestrial laser scanning (TLS) and close-range photogrammetry from an unmanned aerial vehicle (UAV) for generating a high-resolution point cloud and digital elevation model (DEM) of a complex alpine terrain. The approach is demonstrated using a small study area in the upper part of a deglaciated valley in the Tatry Mountains, Slovakia. The more accurate TLS point cloud was supplemented by the UAV point cloud in areas with insufficient TLS data coverage. The accuracy of the iterative closest point adjustment of the UAV and TLS point clouds was in the order of several centimeters but standard deviation of the mutual orientation of TLS scans was in the order of millimeters. The generated high-resolution DEM was compared to SRTM DEM, TanDEM-X and national DMR3 DEM products confirming an excellent applicability in a wide range of geomorphologic applications.The general advantage of laser scanning over photogrammetry is in the ability of sampling several kinds of surfaces (e.g., top of vegetation canopy, inter-canopy surfaces, and ground) which are in the line of sight of the laser beam until impermeable surface restrains further penetration of the laser energy. UAV-SfM has become a low-cost alternative to TLS, generating point clouds with comparable accuracies to TLS albeit with the limitation of sampling the top surface in the field of view. Either way, in cases where TLS or UAV-SfM are used separately, data shadows originate in areas which are obscured in the sensor's field of view [23,29] (Figure 1). Complementing the unsampled areas with the surface altitude measurements is possible by sensing the area from multiple positions and different viewing perspectives by changing the location of the sensor. Zhang and Lin [30] provide a systematic overview of the lidar and photogrammetric data fusion. Cawood et al. [7] showed there is no exclusive method for capturing complex 3D geometry in the case study of 3D modelling a large boulder with distinct geological structural features. Combination of TLS and UAV-SfM provided the most satisfying results to capture the geometric complexity of the object of interest for structural analysis. A similar approach of combining different viewing geometry of TLS and photogrammetry was demonstrated in 3D modelling of a historical city by [23]. Planning the data collection in the mentioned studies concerned environments with a relatively easy access for the technology and the surveying pe...

show abstract

Optimization of UAVs‐SfM data collection in aeolian landform morphodynamics: a case study from the Gonghe Basin, China

Luo

Shao

Che

et al. 2020

Earth Surf Processes Landf

View full text Add to dashboard Cite

UAVs-SfM (unmanned aerial vehicles-structure-from-motion) systems can generate high-resolution three-dimensional (3D) topographic models of aeolian landforms. To explore the optimization of UAVs-SfM for use in aeolian landform morphodynamics, this study tested flight parameters for two contrasting aeolian landform areas (free dune and blowout) to assess the 3D reconstruction accuracy of the UAV survey compared with field point measurements using differential RTK-GPS (real-time kinematic-global positioning system). The results reveal the optimum UAVs-SfM flight setup at the free-dune site was: flying height ¼ 74m, camera tilt angle ¼ À90°, photograph overlap ratio ¼ 85%/70% (heading/sideways). The horizontal/vertical location error was around 0.028-0.055m and 0.053-0.069m, respectively, and a point cloud density of 463/m 3 was found to generate a clear texture using these flying parameters. For the < 20m deep blowout the optimum setup with highest accuracy and the lowest cliff texture distortion was: flying height ¼ 74m combined camera tilt angle ¼ À90°and À60°, photograph overlap ratio ¼ 85%/70% (heading/ sideways), and an evenly distributed GCPs (ground control points) density of 42/km 2 using these flying parameters. When the depth of the blowouts exceeded 40m, the optimum flight/survey parameters changed slightly to account for more challenging cliff texture generation: flying height ¼ 80m (with À90°and À60°combined camera tilt angle), GCPs density ¼ 63/km 2 to generate horizontal and vertical location error of 0.024m and 0.050m, respectively, and point cloud density of 2597.11/m 3. The main external factors that affect the successful 3D reconstruction of aeolian landforms using UAVs-SfM are the weather conditions, manipulation errors, and instrument system errors. The UAVs-SfM topographic monitoring results demonstrate that UAVs provide a viable and robust means for aeolian landform morphodynamics monitoring. Importantly, the rapid and high precision 3D reconstruction processes were significantly advanced using the optimal flight parameters reported here.

show abstract

Reconstruction of extreme topography from UAV structure from motion photogrammetry

Cited by 87 publications

References 43 publications

UAV survey of a coastal cliff face – Selection of the best imaging angle

UAV survey of a coastal cliff face – Selection of the best imaging angle

Combined Use of Terrestrial Laser Scanning and UAV Photogrammetry in Mapping Alpine Terrain

Optimization of UAVs‐SfM data collection in aeolian landform morphodynamics: a case study from the Gonghe Basin, China

Contact Info

Product

Resources

About