scholarly journals THE INFLUENCE OF FLIGHT CONFIGURATION, CAMERA CALIBRATION, AND GROUND CONTROL POINTS FOR DIGITAL TERRAIN MODEL AND ORTHOMOSAIC GENERATION USING UNMANNED AERIAL VEHICLES IMAGERY

2021 ◽  
Vol 27 (2) ◽  
Author(s):  
Marcos Vinícius Yodono Garcia ◽  
Henrique Cândido de Oliveira
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Camera Calibration ◽  
Digital Terrain Model ◽  
Ground Control ◽  
Control Points ◽  
Terrain Model ◽  
Digital Terrain ◽  
Ground Control Points ◽  
Aerial Vehicles

Development of a 3D Viewer for georeferencing and monoplotting of historical terrestrial images.

2020 ◽  
Author(s):  
Sebastian Flöry ◽  
Camillo Ressl ◽  
Gerhard Puercher ◽  
Norbert Pfeifer ◽  
Markus Hollaus ◽  
...  
Keyword(s):  
Digital Terrain Model ◽  
Local Scale ◽  
Aerial Imagery ◽  
Ground Control ◽  
Control Points ◽  
Mountainous Regions ◽  
Terrain Model ◽  
Digital Terrain ◽  
Ground Control Points ◽  
Selection Of

<p>Mountain regions are disproportionately affected by global warming and changing precipitation conditions. Especially the strong variations within high mountain ranges at the local scale require additional sources in order to quantify changes within this challenging environment. With the emergence of alpine tourism, terrestrial photographs became available by the end of 1800, predating aerial imagery for the selected study areas by 50 years. Due to the earlier availability and oblique acquisition geometry these images are a promising source for quantifying changes within mountainous regions at the local scale. Within the research project SEHAG, methods to process these images and to analyse their potential to quantify and describe environmental changes are developed and applied to study areas in Austria and Italy.</p><p>One of the prerequisites for the estimation of changes based on terrestrial imagery is the calculation of the corresponding object point for each pixel in a global coordinate system resulting in a georeferenced orthorectified image. This can be achieved by intersecting the ray defined by the projection center of the camera and each pixel with a digital terrain model, a process known as monoplotting.</p><p>So far 1000 terrestrial images with unknown interior and exterior orientation have been collected from various archives for the selected study areas Kaunertal, Horlachtal (both Tyrol, Austria) and Martelltal (South Tyrol, Italy). In order to estimate all camera parameters a 3D viewer for the selection of ground control points has been developed and implemented. The estimation of the exterior and interior orientation is done in OrientAL. </p><p>Preliminary results for selected images show, that especially the developed 3D viewer is an important improvement for the selection of well distributed ground control points and the accurate estimation of the exterior and interior orientation. Monoplotting depends on a digital terrain model, which cannot be computed from the terrestrial images alone due to missing overlap and different acquisitions times. Hence, the combination with historical digital terrain models derived from aerial imagery is necessary to minimize errors introduced due to changes in topography until today. While the large amount of terrestrial images with their oblique acquisition geometries can be exploited to fill occluded areas by combining the results from multiple images, the partly missing or inaccurate temporal information poses another limitation.</p><p>With this large image collection, for the first time, we are able to evaluate the use of historical oblique terrestrial photographs for change detection in a systematic manner. This will promote knowledge about challenges, limitations and the achievable accuracy of monoplotting within mountainous regions. The work is part of the SEHAG project (project number I 4062) funded by the Austrian Science Fund (FWF).</p>

scholarly journals BADANIE MOŻLIWOŚCI WYKORZYSTANIA ZOBRAZOWAŃ DYNAMICZNYCH (WIDEO) Z NISKIEGO PUŁAPU LOTNICZEGO (BSP) DO OPRACOWAŃ FOTOGRAMETRYCZNYCH

1970 ◽  
pp. 53-64
Author(s):  
ADAM MŁYNARCZYK ◽  
SŁAWOMIR KRÓLEWICZ ◽  
PAWEŁ RUTKOWSKI
Keyword(s):  
High Altitude ◽  
Unmanned Aerial Vehicles ◽  
Point Cloud ◽  
Digital Terrain Model ◽  
Image Data ◽  
Terrain Model ◽  
Digital Terrain ◽  
Aerial Vehicles ◽  
The Creation ◽  
Recorded Image

The use of unmanned aerial vehicles is becoming more and more popular for making high-altitude and orthophotomap models. In this process, series of images are taken at specific intervals, usually lasting several seconds. This article demonstrates the ability to make models and orthophotomaps from dynamic images – video recorded from UAV. The best mutual coverage of photographs was indicated (95–96%) and the photogrammetric process for joining images was presented, through the creation of a point cloud to obtain a digital terrain model and the orotfotomap. The data was processed in 150 different variants and the usefulness of this method was demonstrated. Problems and errors that may occur during the processing of recorded image data are also described.

scholarly journals UAV PHOTOGRAMMETRY IMPLEMENTATION TO ENHANCE LAND SURVEYING, COMPARISONS AND POSSIBILITIES

2016 ◽  
Vol XLII-2/W2 ◽  
pp. 107-114 ◽  
Author(s):  
R. El Meouche ◽  
I. Hijazi ◽  
P. A. Poncet ◽  
M. Abunemeh ◽  
M. Rezoug
Keyword(s):  
Unmanned Aerial Vehicles ◽  
3D Modeling ◽  
Maximum Error ◽  
Ground Control ◽  
Control Points ◽  
Ground Control Points ◽  
Area Of Interest ◽  
Aerial Vehicles ◽  
Land Surveying ◽  
Archeological Site

The use of Unmanned Aerial Vehicles (UAVs) for surveying is now widespread and operational for several applications – quarry monitoring, archeological site surveys, forest management and 3D modeling for buildings, for instance. UAV is increasingly used by land surveyors especially for those kinds of projects. It is still ambiguous whether UAV can be applicable for smaller sites and property division. Therefore, the objective of this research is to extract a vectorized plan utilizing a UAV for a small site and investigate the possibility of an official land surveyor exploiting and certificating it. To do that, two plans were created, one using a UAV and another utilizing classical land surveyor instruments (Total Station). A comparison was conducted between the two plans to evaluate the accuracy of the UAV technique compared to the classical one. Moreover, other parameters were also considered such as execution time and the surface covered. The main problems associated with using a UAV are the level of precision and the visualization of the whole area. The results indicated that the precision is quite satisfactory with a maximum error of 1.0 cm on ground control points, and 4 cm for the rest of the model. On the other hand, the results showed that it is not possible to represent the whole area of interest utilizing a UAV, due to vegetation.

scholarly journals THE INFLUENCE OF GROUND CONTROL POINTS CONFIGURATION AND CAMERA CALIBRATION FOR DTM AND ORTHOMOSAIC GENERATION USING IMAGERY OBTAINED FROM A LOW-COST UAV

2020 ◽  
Vol V-1-2020 ◽  
pp. 239-244
Author(s):  
M. V. Y. Garcia ◽  
H. C. Oliveira
Keyword(s):  
Low Cost ◽  
Digital Terrain Model ◽  
Flying Height ◽  
Ground Control ◽  
Optimum Number ◽  
Control Points ◽  
Digital Products ◽  
Positional Accuracy ◽  
Terrain Model ◽  
Ground Control Points

Abstract. Technological improvement of Unmanned Aerial Vehicles (UAVs) and computer vision algorithms, such as Structured-from-Motion (SfM) and Multi-view Stereo (MVS) have provided the possibility for high-resolution mapping and high-density point cloud generation using low-cost equipment and sensors. Orthomosaics and Digital Terrain Model (DTM) are the main digital products considering mapping purposes. Their quality is directly related to the sensors boarded on the UAV and data processing. Ground Control Points (GCPs) are used in the process of indirect georeferencing and also to model the lens distortions. The number of GCPs used in this process affects the positional accuracy of the final products. This study aims to determine the optimum number of GCPs to achieve high accuracy orthomosaics and DTM. To obtain this optimum number, an area of 3.85 ha was mapped with a low-cost UAV DJI Phantom 4 Advanced at 31 m flying height, lateral and longitudinal overlap of 90% and 80%, respectively, and using 22 checkpoints for quality assessment. For the experiments, different configuration were used both for the number of GCPs and for the use of self-calibration process or pre-calibrated camera IOP (Interior Orientation Parameters). The results show that for the flight configuration used in this work and for the mentioned UAV, a total of 5 GCPs, with pre-calibrated camera IOP, yields an accuracy of 0.023 m for X, 0.031 m for Y and 0.033 m for Z.

scholarly journals Remotely-piloted aerial system for photogrammetry: orthoimage generation for mapping applications

Geografie ◽  
2016 ◽  
Vol 121 (3) ◽  
pp. 349-367 ◽  
Author(s):  
Jūratė Sužiedelytė Visockienė ◽  
Domantas Bručas ◽  
Renata Bagdžiūnaitė ◽  
Rūta Puzienė ◽  
Arminas Stanionis ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Camera Calibration ◽  
Digital Terrain Model ◽  
Field Testing ◽  
Terrain Model ◽  
Aerial Photogrammetry ◽  
Aerial Vehicles ◽  
Camera Location ◽  
Commercial Off The Shelf ◽  
Calibration Parameters

Recently the tendency of replacing aircraft by light, simple, cheap unmanned aerial vehicles for the purposes of updating the field of aerial photogrammetry has been observed. The article deals with the issues of project calculations concerning unmanned aerial vehicles flights and an analysis of the images acquired during field-testing flights. In this article, we analyze the images acquired by mini unmanned aerial vehicles, in particular, the 1.8 plane and the plane SOA-1 that have been processed by a commercial off-the-shelf software package Agisoft PhotoScan (Russia). The 1.8 plane was equipped with the camera Canon S100, containing known camera calibration parameters. These parameters were used for the processing of the image. The aircraft SOA-1 had the camera Canon PowerShot SX280 HS without camera calibration parameters. The camera parameters were calculated by software during the processing image. The paper also presents results of an investigation into the average camera location errors during the test flights, the quality of orthoimage generation by point cloud and a digital terrain model.

scholarly journals Analysis of the impacts on the quality of UAV photogrammetric products

2020 ◽  
Vol 64 (04) ◽  
pp. 489-507
Author(s):  
Mojca Kosmatin Fras ◽  
Urška Drešček ◽  
Anka Lisec ◽  
Dejan Grigillo
Keyword(s):  
Data Acquisition ◽  
Unmanned Aerial Vehicles ◽  
Spatial Data ◽  
Point Clouds ◽  
Ground Control ◽  
Control Points ◽  
Positional Accuracy ◽  
Ground Control Points ◽  
Aerial Vehicles

Unmanned aerial vehicles, equipped with various sensors and devices, are increasingly used to acquire geospatial data in geodesy, geoinformatics, and environmental studies. In this context, a new research and professional field has been developed – UAV photogrammetry – dealing with photogrammetry data acquisition and data processing, acquired by unmanned aerial vehicles. In this study, we analyse the selected factors that impact the quality of data provided using UAV photogrammetry, with the focus on positional accuracy; they are discussed in three groups: (a) factors related to the camera properties and the quality of images; (b) factors related to the mission planning and execution; and (c) factors related to the indirect georeferencing of images using ground control points. These selected factors are analysed based on the detailed review of relevant scientific publications. Additionally, the influence of the number of ground control points and their spatial distribution on point clouds' positional accuracy has been investigated for the case study. As the conclusion, key findings and recommendations for UAV photogrammetric projects are given; we have highlighted the importance of suitable lighting and weather conditions when performing UAV missions for spatial data acquisition, quality equipment, appropriate parameters of UAV data acquisition, and a sufficient number of ground control points, which should be determined with the appropriate positional accuracy and their correct distribution in the field.

scholarly journals DTM GENERATION WITH UAV BASED PHOTOGRAMMETRIC POINT CLOUD

2017 ◽  
Vol XLII-4/W6 ◽  
pp. 77-79 ◽  
Author(s):  
N. Polat ◽  
M. Uysal
Keyword(s):  
Low Cost ◽  
Laser Scanner ◽  
Digital Camera ◽  
Digital Terrain Model ◽  
Field Work ◽  
Generation Process ◽  
Control Points ◽  
Terrain Model ◽  
Digital Terrain ◽  
Ground Control Points

Nowadays Unmanned Aerial Vehicles (UAVs) are widely used in many applications for different purposes. Their benefits however are not entirely detected due to the integration capabilities of other equipment such as; digital camera, GPS, or laser scanner. The main scope of this paper is evaluating performance of cameras integrated UAV for geomatic applications by the way of Digital Terrain Model (DTM) generation in a small area. In this purpose, 7 ground control points are surveyed with RTK and 420 photographs are captured. Over 30 million georeferenced points were used in DTM generation process. Accuracy of the DTM was evaluated with 5 check points. The root mean square error is calculated as 17.1 cm for an altitude of 100 m. Besides, a LiDAR derived DTM is used as reference in order to calculate correlation. The UAV based DTM has o 94.5 % correlation with reference DTM. Outcomes of the study show that it is possible to use the UAV Photogrammetry data as map producing, surveying, and some other engineering applications with the advantages of low-cost, time conservation, and minimum field work.

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