scholarly journals WETLAND ASSESSMENT USING UNMANNED AERIAL VEHICLE (UAV) PHOTOGRAMMETRY

2016 ◽  
Vol XLI-B1 ◽  
pp. 781-788 ◽  
Author(s):  
M. A. Boon ◽  
R. Greenfield ◽  
S. Tesfamichael
Keyword(s):  
Mean Squared Error ◽  
Health Assessment ◽  
Digital Camera ◽  
Point Clouds ◽  
Field Studies ◽  
3D Models ◽  
Wetland Delineation ◽  
Technological Advancement ◽  
Wetland Assessment ◽  
Wetland Ecosystems

The use of Unmanned Arial Vehicle (UAV) photogrammetry is a valuable tool to enhance our understanding of wetlands. Accurate planning derived from this technological advancement allows for more effective management and conservation of wetland areas. This paper presents results of a study that aimed at investigating the use of UAV photogrammetry as a tool to enhance the assessment of wetland ecosystems. The UAV images were collected during a single flight within 2½ hours over a 100 ha area at the Kameelzynkraal farm, Gauteng Province, South Africa. An AKS Y-6 MKII multi-rotor UAV and a digital camera on a motion compensated gimbal mount were utilised for the survey. Twenty ground control points (GCPs) were surveyed using a Trimble GPS to achieve geometrical precision and georeferencing accuracy. Structure-from-Motion (SfM) computer vision techniques were used to derive ultra-high resolution point clouds, orthophotos and 3D models from the multi-view photos. The geometric accuracy of the data based on the 20 GCP’s were 0.018 m for the overall, 0.0025 m for the vertical root mean squared error (RMSE) and an over all root mean square reprojection error of 0.18 pixel. The UAV products were then edited and subsequently analysed, interpreted and key attributes extracted using a selection of tools/ software applications to enhance the wetland assessment. The results exceeded our expectations and provided a valuable and accurate enhancement to the wetland delineation, classification and health assessment which even with detailed field studies would have been difficult to achieve.

scholarly journals WETLAND ASSESSMENT USING UNMANNED AERIAL VEHICLE (UAV) PHOTOGRAMMETRY

2016 ◽  
Vol XLI-B1 ◽  
pp. 781-788
Author(s):  
M. A. Boon ◽  
R. Greenfield ◽  
S. Tesfamichael
Keyword(s):  
Mean Squared Error ◽  
Health Assessment ◽  
Digital Camera ◽  
Point Clouds ◽  
Field Studies ◽  
3D Models ◽  
Wetland Delineation ◽  
Technological Advancement ◽  
Wetland Assessment ◽  
Wetland Ecosystems

The use of Unmanned Arial Vehicle (UAV) photogrammetry is a valuable tool to enhance our understanding of wetlands. Accurate planning derived from this technological advancement allows for more effective management and conservation of wetland areas. This paper presents results of a study that aimed at investigating the use of UAV photogrammetry as a tool to enhance the assessment of wetland ecosystems. The UAV images were collected during a single flight within 2½ hours over a 100 ha area at the Kameelzynkraal farm, Gauteng Province, South Africa. An AKS Y-6 MKII multi-rotor UAV and a digital camera on a motion compensated gimbal mount were utilised for the survey. Twenty ground control points (GCPs) were surveyed using a Trimble GPS to achieve geometrical precision and georeferencing accuracy. Structure-from-Motion (SfM) computer vision techniques were used to derive ultra-high resolution point clouds, orthophotos and 3D models from the multi-view photos. The geometric accuracy of the data based on the 20 GCP’s were 0.018 m for the overall, 0.0025 m for the vertical root mean squared error (RMSE) and an over all root mean square reprojection error of 0.18 pixel. The UAV products were then edited and subsequently analysed, interpreted and key attributes extracted using a selection of tools/ software applications to enhance the wetland assessment. The results exceeded our expectations and provided a valuable and accurate enhancement to the wetland delineation, classification and health assessment which even with detailed field studies would have been difficult to achieve.

scholarly journals WETLAND HYDROLOGICAL INTEGRITY ASSESSMENT WITH UNMANNED AERIAL SYSTEMS (UAS)

2017 ◽  
Vol XLII-3/W2 ◽  
pp. 31-35
Author(s):  
M. A. Boon ◽  
S. Tesfamichael
Keyword(s):  
High Resolution ◽  
Health Assessment ◽  
Digital Camera ◽  
Point Clouds ◽  
Field Studies ◽  
Change Score ◽  
Management Decision ◽  
Unmanned Aerial Systems ◽  
Wetland Ecosystems ◽  
Integrity Assessment

A key component of the health status of a wetland ecosystem is the present hydrological integrity. The analysis of on-site activities that impact on the hydrology of a particular wetland was undertaken using an Unmanned Aerial System (UAS) in combination with field studies. The WET-Health methodology was followed for the hydrological assessment, where wetland health is a measure of the deviation of a wetland’s structure and function from its natural reference condition. The extent and nature of activities within the wetland such as impoundments, excavations and indicators of visible damage such as erosion gullies was determined through high resolution UAS mapping using a commercial off-the-shelf digital camera. Structure from Motion (SfM) computer vision techniques were used to derive ultra-high resolution point clouds, orthophotos, digital elevation models (DEMs) and digital terrain models (DTMs). Visual and statistical analyses of the point clouds and surface models were used to derive detailed information useful for enhanced hydrological health assessment of the wetland. The WET-Health hydrology module completed with the aid of the UAS products still indicated that the hydrology of the wetland is completely modified as indicated by the “F” Present Ecological State (PES) category and that the hydrological state of the wetland will deteriorate (change score). However a higher impact score was determined through the enhanced visualisation and completion of scale-appropriate measurements of hydrological features. In conclusion, the use of UAS can significantly enhance the assessment of surface hydrology of wetlands and thereby allow for more effective management, decision making and conservation of wetland ecosystems.

scholarly journals Photo Scanner 3D Survey for Monitoring Historical Monuments. the Case History of Porta Praetoria in Aosta

2011 ◽  
Vol 6 ◽  
pp. 314-322 ◽  
Author(s):  
Paolo Salonia ◽  
Tommaso Leti Messina ◽  
Andrea Marcolongo ◽  
Lorenzo Appolonia
Keyword(s):  
Cultural Heritage ◽  
New Technology ◽  
Digital Camera ◽  
Point Clouds ◽  
3D Models ◽  
Stone Decay ◽  
Decay Kinetics ◽  
Image Block ◽  
Building Site ◽  
Historical Monuments

Accessibility to cultural heritage is one of the most important factors in cultural heritage preservation, as it assures knowledge, monitoring, Public Administration management and a wide interest on cultural heritage sites. Nowdays 3D surveys give the geometric basis for an effective artefact reconstruction but most of the times 3D data are not completely and deeply investigated to extract other useful information on historical monuments for their conservation and safeguard. The Cultural Heritage Superintendence of Aosta decided to run a time continual project of monitoring of the Praetorian Roman Gate with the collaboration of the ITABC, CNR of Italy. The Praetorian Roman Gate in Aosta, Italy, of Augustus ages, is one of the most well-known roman monumental gates, it is a double gate with three arches each side, 12 meters high, 20 meters wide, made of pudding stone ashlars, Badoglio, travertine, marble blocks and other stone insertion due to restorations between 1600 and 1950. In years 2000 a final restoration intervention brought the gate at the present state of art, within the frame of a restoration and conservation building site with the purpose of treat the different decay pathologies and conditions. A complete 3D geometric survey campaign has been the first step for the monitoring of the gate morphologic changes and decay progress in time. The main purpose is to collect both quantitative data, related to the geometry of the gate, and the qualitative data, related to the chromatic change on the surface due to the stone decay. The geometric data with colour information permits to associate materials and stone pathologies to chemical or mechanical actions and to understand and analyse superficial decay kinetics. The colours survey will also permit to directly locate on the 3D model areas of different stratigraphic units. The project aims to build a rigorous quantitative-qualitative database so to be uploaded into a GIS. The GIS will become the monitoring main means. Considering the huge dimension of the gate and its urban location a multi-scale approach has been considered. Controlled and free images have been taken from the ground and the top of the gate so to reconstruct all the walls and the upper cover. A topographic survey has been done so to be able to control and relate all the different acquisitions. It has been chosen a Photo Scanner 3D system. It is a photogrammetry-based survey technology for point clouds acquisition and 3D models configuration, from digital images processing. This technology allows to obtain point clouds (xyz coordinates) with RGB information and geometries at different levels of complexity by processing a number of images taken with a limited set of constraints, with the use of a simple acquisition equipment and through an image matching algorithm (ZScan, by Menci Software). Due to the high walls of the arch gates, the higher part has been surveyed with a remote controlled drone (UAV Unmanned Aerial Vehicle) with a digital camera on it, so to take pictures up to the maximum altitude and with different shooting angles ( 90 and 45 degree). This is a new technology which permits to survey inaccessible parts of a high monument with ease and accuracy, by collecting redundant pictures later bound together by an image block algorithm. This paper aims to present the survey experience architectural monuments trough the application of a trifocal quick photogrammetric system, in surveying at different scales and for different purposes.

scholarly journals INTEGRATION OF GEODATA IN DOCUMENTING CASTLE RUINS

2016 ◽  
Vol XLI-B3 ◽  
pp. 345-349
Author(s):  
P. Delis ◽  
M. Wojtkowska ◽  
P. Nerc ◽  
I. Ewiak ◽  
A. Lada
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Camera ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
3D Models ◽  
Digital Imagery ◽  
Historical Structures ◽  
Three Dimensional Models ◽  
Different Sources

Textured three dimensional models are currently the one of the standard methods of representing the results of photogrammetric works. A realistic 3D model combines the geometrical relations between the structure’s elements with realistic textures of each of its elements. Data used to create 3D models of structures can be derived from many different sources. The most commonly used tool for documentation purposes, is a digital camera and nowadays terrestrial laser scanning (TLS). Integration of data acquired from different sources allows modelling and visualization of 3D models historical structures. Additional aspect of data integration is possibility of complementing of missing points for example in point clouds. The paper shows the possibility of integrating data from terrestrial laser scanning with digital imagery and an analysis of the accuracy of the presented methods. The paper describes results obtained from raw data consisting of a point cloud measured using terrestrial laser scanning acquired from a Leica ScanStation2 and digital imagery taken using a Kodak DCS Pro 14N camera. The studied structure is the ruins of the Ilza castle in Poland.

scholarly journals GENERATING ACCURATE 3D MODELS OF ARCHITECTURAL HERITAGE STRUCTURES USING LOW-COST CAMERA AND OPEN SOURCE ALGORITHMS

2017 ◽  
Vol XLII-5/W1 ◽  
pp. 99-104
Author(s):  
M. Zacharek ◽  
P. Delis ◽  
M. Kedzierski ◽  
A. Fryskowska
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Web Application ◽  
Low Cost ◽  
Digital Camera ◽  
Point Clouds ◽  
3D Models ◽  
Dense Image ◽  
Dense Point ◽  
Historical Heritage

These studies have been conductedusing non-metric digital camera and dense image matching algorithms, as non-contact methods of creating monuments documentation.In order toprocess the imagery, few open-source software and algorithms of generating adense point cloud from images have been executed. In the research, the OSM Bundler, VisualSFM software, and web application ARC3D were used. Images obtained for each of the investigated objects were processed using those applications, and then dense point clouds and textured 3D models were created. As a result of post-processing, obtained models were filtered and scaled.The research showedthat even using the open-source software it is possible toobtain accurate 3D models of structures (with an accuracy of a few centimeters), but for the purpose of documentation and conservation of cultural and historical heritage, such accuracy can be insufficient.

scholarly journals INTEGRATION OF GEODATA IN DOCUMENTING CASTLE RUINS

2016 ◽  
Vol XLI-B3 ◽  
pp. 345-349 ◽  
Author(s):  
P. Delis ◽  
M. Wojtkowska ◽  
P. Nerc ◽  
I. Ewiak ◽  
A. Lada
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Digital Camera ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
3D Models ◽  
Digital Imagery ◽  
Historical Structures ◽  
Three Dimensional Models ◽  
Different Sources

Textured three dimensional models are currently the one of the standard methods of representing the results of photogrammetric works. A realistic 3D model combines the geometrical relations between the structure’s elements with realistic textures of each of its elements. Data used to create 3D models of structures can be derived from many different sources. The most commonly used tool for documentation purposes, is a digital camera and nowadays terrestrial laser scanning (TLS). Integration of data acquired from different sources allows modelling and visualization of 3D models historical structures. Additional aspect of data integration is possibility of complementing of missing points for example in point clouds. The paper shows the possibility of integrating data from terrestrial laser scanning with digital imagery and an analysis of the accuracy of the presented methods. The paper describes results obtained from raw data consisting of a point cloud measured using terrestrial laser scanning acquired from a Leica ScanStation2 and digital imagery taken using a Kodak DCS Pro 14N camera. The studied structure is the ruins of the Ilza castle in Poland.

scholarly journals Symmetry Analysis of Oriental Polygonal Pagodas Using 3D Point Clouds for Cultural Heritage

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1228
Author(s):  
Ting On Chan ◽  
Linyuan Xia ◽  
Yimin Chen ◽  
Wei Lang ◽  
Tingting Chen ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Unmanned Aerial Vehicle ◽  
Point Cloud ◽  
Geometric Model ◽  
Digital Camera ◽  
Point Clouds ◽  
Symmetry Analysis ◽  
3D Point Clouds ◽  
Transmission Towers ◽  
Aerial Vehicle

Ancient pagodas are usually parts of hot tourist spots in many oriental countries due to their unique historical backgrounds. They are usually polygonal structures comprised by multiple floors, which are separated by eaves. In this paper, we propose a new method to investigate both the rotational and reflectional symmetry of such polygonal pagodas through developing novel geometric models to fit to the 3D point clouds obtained from photogrammetric reconstruction. The geometric model consists of multiple polygonal pyramid/prism models but has a common central axis. The method was verified by four datasets collected by an unmanned aerial vehicle (UAV) and a hand-held digital camera. The results indicate that the models fit accurately to the pagodas’ point clouds. The symmetry was realized by rotating and reflecting the pagodas’ point clouds after a complete leveling of the point cloud was achieved using the estimated central axes. The results show that there are RMSEs of 5.04 cm and 5.20 cm deviated from the perfect (theoretical) rotational and reflectional symmetries, respectively. This concludes that the examined pagodas are highly symmetric, both rotationally and reflectionally. The concept presented in the paper not only work for polygonal pagodas, but it can also be readily transformed and implemented for other applications for other pagoda-like objects such as transmission towers.

scholarly journals DIRECT CO-REGISTRATION OF TIR IMAGES AND MLS POINT CLOUDS BY CORRESPONDING KEYPOINTS

2019 ◽  
Vol IV-2/W7 ◽  
pp. 235-242
Author(s):  
J. Zhu ◽  
Y. Xu ◽  
L. Hoegner ◽  
U. Stilla
Keyword(s):  
Condition Monitoring ◽  
Point Cloud ◽  
Infrared Image ◽  
Point Clouds ◽  
Thermal Infrared ◽  
3D Models ◽  
Corner Detection ◽  
Leakage Detection ◽  
Registration Process ◽  
Camera Pose

<p><strong>Abstract.</strong> In this work, we discussed how to directly combine thermal infrared image (TIR) and the point cloud without additional assistance from GCPs or 3D models. Specifically, we propose a point-based co-registration process for combining the TIR image and the point cloud for the buildings. The keypoints are extracted from images and point clouds via primitive segmentation and corner detection, then pairs of corresponding points are identified manually. After that, the estimated camera pose can be computed with EPnP algorithm. Finally, the point cloud with thermal information provided by IR images can be generated as a result, which is helpful in the tasks such as energy inspection, leakage detection, and abnormal condition monitoring. This paper provides us more insight about the probability and ideas about the combining TIR image and point cloud.</p>

scholarly journals INTEGRATING TERRESTRIAL LIDAR WITH POINT CLOUDS CREATED FROM UNMANNED AERIAL VEHICLE IMAGERY

2015 ◽  
Vol XL-1/W4 ◽  
pp. 97-101 ◽  
Author(s):  
M. Leslar
Keyword(s):  
Point Cloud ◽  
Inertial Navigation System ◽  
Vertical Wall ◽  
Digital Camera ◽  
Point Clouds ◽  
Digital Photogrammetry ◽  
Lidar System ◽  
Terrestrial Lidar ◽  
Stereo Imagery ◽  
Aerial Vehicle

Using unmanned aerial vehicles (UAV) for the purposes of conducting high-accuracy aerial surveying has become a hot topic over the last year. One of the most promising means of conducting such a survey involves integrating a high-resolution non-metric digital camera with the UAV and using the principals of digital photogrammetry to produce high-density colorized point clouds. Through the use of stereo imagery, precise and accurate horizontal positioning information can be produced without the need for integration with any type of inertial navigation system (INS). Of course, some form of ground control is needed to achieve this result. Terrestrial LiDAR, either static or mobile, provides the solution. Points extracted from Terrestrial LiDAR can be used as control in the digital photogrammetry solution required by the UAV. In return, the UAV is an affordable solution for filling in the shadows and occlusions typically experienced by Terrestrial LiDAR. In this paper, the accuracies of points derived from a commercially available UAV solution will be examined and compared to the accuracies achievable by a commercially available LIDAR solution. It was found that the LiDAR system produced a point cloud that was twice as accurate as the point cloud produced by the UAV’s photogrammetric solution. Both solutions gave results within a few centimetres of the control field. In addition the about of planar dispersion on the vertical wall surfaces in the UAV point cloud was found to be multiple times greater than that from the horizontal ground based UAV points or the LiDAR data.

scholarly journals ANALYSIS OF 3D BUILDING MODELS ACCURACY BASED ON THE AIRBORNE LASER SCANNING POINT CLOUDS

2018 ◽  
Vol XLII-2 ◽  
pp. 797-804 ◽  
Author(s):  
W. Ostrowski ◽  
M. Pilarska ◽  
J. Charyton ◽  
K. Bakuła
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Large Scale ◽  
Point Clouds ◽  
3D Models ◽  
Airborne Laser Scanning ◽  
Aerial Images ◽  
Statistical Parameters ◽  
Airborne Laser ◽  
Building Models

Creating 3D building models in large scale is becoming more popular and finds many applications. Nowadays, a wide term “3D building models” can be applied to several types of products: well-known CityGML solid models (available on few Levels of Detail), which are mainly generated from Airborne Laser Scanning (ALS) data, as well as 3D mesh models that can be created from both nadir and oblique aerial images. City authorities and national mapping agencies are interested in obtaining the 3D building models. Apart from the completeness of the models, the accuracy aspect is also important. Final accuracy of a building model depends on various factors (accuracy of the source data, complexity of the roof shapes, etc.). In this paper the methodology of inspection of dataset containing 3D models is presented. The proposed approach check all building in dataset with comparison to ALS point clouds testing both: accuracy and level of details. Using analysis of statistical parameters for normal heights for reference point cloud and tested planes and segmentation of point cloud provides the tool that can indicate which building and which roof plane in do not fulfill requirement of model accuracy and detail correctness. Proposed method was tested on two datasets: solid and mesh model.

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