scholarly journals COMBINATION OF TERRESTRIAL LASERSCANNING, UAV AND CLOSE-RANGE PHOTOGRAMMETRY FOR 3D RECONSTRUCTION OF COMPLEX CHURCHES IN GEORGIA

Author(s):  
T. Luhmann ◽  
M. Chizhova ◽  
D. Gorkovchuk ◽  
H. Hastedt ◽  
N. Chachava ◽  
...  

<p><strong>Abstract.</strong> In September 2018, photogrammetric images and terrestrial laser scans were carried out as part of a measurement campaign for the three-dimensional recording of several historic churches in Tbilisi (Georgia). The aim was the complete spatial reconstruction with a spatial resolution and accuracy of approx. 1cm under partly difficult external conditions, which required the use of different measurement techniques.</p><p>The local measurement data were collected by two laser scanning campaigns (Leica BLK360 and Faro Focus 3D X330), two UAV flights and two terrestrial image sets. The photogrammetric point clouds were calculated with the SfM programs AgiSoft PhotoScan and RealityCapture taking into account the control points from the Faro laser scan. The mean residual errors from the registrations or photogrammetric evaluations are 4-12mm, depending on the selected software. The best completeness and quality of the resulting 3D model was achieved by using laserscan data and images simultaneously.</p>

Drones ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 53
Author(s):  
Thomas Luhmann ◽  
Maria Chizhova ◽  
Denys Gorkovchuk

In September 2018, photogrammetric images and terrestrial laser scans were carried out as part of a measurement campaign for the three-dimensional recording of several historic churches in Tbilisi (Georgia). The aim was the complete spatial reconstruction with a spatial resolution and accuracy of approx. 1 cm under partly difficult external conditions, which required the use of different measurement techniques. The local measurement data were collected by two laser scanning campaigns (Leica BLK360 and Faro Focus 3D X330), several UAV flights and two terrestrial image sets. The photogrammetric point clouds were calculated with the image-based modelling programs AgiSoft and RealityCapture taking into account the control points from the laser scans. The mean residual errors from the registrations or photogrammetric evaluations are 4–16 mm, depending on the selected software, size and complexity of the monument and environmental conditions. The best completeness and quality of the resulting 3D model was achieved by using laser scan data and images simultaneously. The article presents recent results obtained with RealityCapture and gives a critical analysis of accuracy and modelling quality.


2018 ◽  
Vol 25 (2) ◽  
pp. 47-56 ◽  
Author(s):  
Marek Kulawiak ◽  
Zbigniew Łubniewski

Abstract The technologies of sonar and laser scanning are an efficient and widely used source of spatial information with regards to underwater and over ground environment respectively. The measurement data are usually available in the form of groups of separate points located irregularly in three-dimensional space, known as point clouds. This data model has known disadvantages, therefore in many applications a different form of representation, i.e. 3D surfaces composed of edges and facets, is preferred with respect to the terrain or seabed surface relief as well as various objects shape. In the paper, the authors propose a new approach to 3D shape reconstruction from both multibeam and LiDAR measurements. It is based on a multiple-step and to some extent adaptive process, in which the chosen set and sequence of particular stages may depend on a current type and characteristic features of the processed data. The processing scheme includes: 1) pre-processing which may include noise reduction, rasterization and pre-classification, 2) detection and separation of objects for dedicated processing (e.g. steep walls, masts), and 3) surface reconstruction in 3D by point cloud triangulation and with the aid of several dedicated procedures. The benefits of using the proposed methods, including algorithms for detecting various features and improving the regularity of the data structure, are presented and discussed. Several different shape reconstruction algorithms were tested in combination with the proposed data processing methods and the strengths and weaknesses of each algorithm were highlighted.


Author(s):  
A. Murtiyoso ◽  
P. Grussenmeyer ◽  
T. Freville

Close-range photogrammetry is an image-based technique which has often been used for the 3D documentation of heritage objects. Recently, advances in the field of image processing and UAVs (Unmanned Aerial Vehicles) have resulted in a renewed interest in this technique. However, commercially ready-to-use UAVs are often equipped with smaller sensors in order to minimize payload and the quality of the documentation is still an issue. In this research, two commercial UAVs (the Sensefly Albris and DJI Phantom 3 Professional) were setup to record the 19<sup>th</sup> century St-Pierre-le-Jeune church in Strasbourg, France. Several software solutions (commercial and open source) were used to compare both UAVs’ images in terms of calibration, accuracy of external orientation, as well as dense matching. Results show some instability in regards to the calibration of Phantom 3, while the Albris had issues regarding its aerotriangulation results. Despite these shortcomings, both UAVs succeeded in producing dense point clouds of up to a few centimeters in accuracy, which is largely sufficient for the purposes of a city 3D GIS (Geographical Information System). The acquisition of close range images using UAVs also provides greater LoD flexibility in processing. These advantages over other methods such as the TLS (Terrestrial Laser Scanning) or terrestrial close range photogrammetry can be exploited in order for these techniques to complement each other.


Author(s):  
F. Carraro ◽  
M. Monego ◽  
C. Callegaro ◽  
A. Mazzariol ◽  
M. Perticarini ◽  
...  

<p><strong>Abstract.</strong> 3D survey methodologies are widely applied to the Cultural Heritage, employing both TLS and close-range photogrammetry with SfM techniques. Laser scanning produces models with high metric reliability and accuracy, whereas the main quality of the 3D photogrammetry is the result in term of photorealistic representation. Many studies have been conducted about the comparison and the integration of these different approaches and the aim of this paper is to contribute with a peculiar case study: the underground Roman bridge of San Lorenzo in Padova (Italy). The investigation regards the resulting point clouds of the intrados (or inner curve) of the central arch, comparing them and providing graphical and analytical outputs. The proposed workflow has the purpose to be a simple but valid tool to detect and evaluate geometrical differences, their significativity and the reliability of the 3D models.</p>


Author(s):  
Z. Majid ◽  
M. F. M. Ariff ◽  
K. M. Idris ◽  
A. R. Yusoff ◽  
K. M. Idris ◽  
...  

The paper describes the used of close-range photogrammetry and terrestrial laser scanning technologies as an innovative technology for acquiring the three-dimensional data of an ancient cave paintings. The close-range photogrammetry technology used in the research was divided in two categories which are the UAV-based close-range photogrammetry and the terrestrialbased close-range photogrammetry. The UAV-based technology involved with the used of calibrated Phantom 4 System while the terrestrial-based technology involved with the calibrated Sony F828 digital camera and pPhotoModeler software. Both stereo and convergent image acquisition techniques were used to acquire the images of the paintings. The ancient cave paintings were also recorded using terrestrial laser scanning technology. In the research, the FARO Focus 3D terrestrial laser scanner was used to capture the three-dimensional point clouds and images of the paintings. The finding shows that both close-range photogrammetry and laser scanning technologies provide excellent solutions to map and to record the ancient paintings. As compared to the conventional method, both close-range photogrammetry and terrestrial laser scanning technology provide a noncontact solution for data acquisition and the data was recorded in digital format for better protection and security.


Author(s):  
B. Alsadik ◽  
M. Gerke ◽  
G. Vosselman

The ongoing development of advanced techniques in photogrammetry, computer vision (CV), robotics and laser scanning to efficiently acquire three dimensional geometric data offer new possibilities for many applications. The output of these techniques in the digital form is often a sparse or dense point cloud describing the 3D shape of an object. Viewing these point clouds in a computerized digital environment holds a difficulty in displaying the visible points of the object from a given viewpoint rather than the hidden points. This visibility problem is a major computer graphics topic and has been solved previously by using different mathematical techniques. However, to our knowledge, there is no study of presenting the different visibility analysis methods of point clouds from a photogrammetric viewpoint. The visibility approaches, which are surface based or voxel based, and the hidden point removal (HPR) will be presented. Three different problems in close range photogrammetry are presented: camera network design, guidance with synthetic images and the gap detection in a point cloud. The latter one introduces also a new concept of gap classification. Every problem utilizes a different visibility technique to show the valuable effect of visibility analysis on the final solution.


Author(s):  
M. Kedzierski ◽  
A. Fryskowska ◽  
D. Wierzbicki ◽  
M. Dabrowska ◽  
A. Grochala

When documenting historical structures and objects, especially delicate artefacts such as pieces of sacred art, only techniques that allow remote, non-contact methods that enable the most precise measurements should be used to obtain data. TLS can be considered as such a technique however in order to obtain complete information for the entire structure, there is usually a need to acquire data from more than one measuring station. In this case, the most important and essential step of processing TLS data is the registration of scans. The paper contains a description of research and analyses concerning the registration of point clouds using three methods: manual, automatic and a combination of the two. The research was carried on measurement data from a historical synagogue. The structure was divided into three parts &ndash; three scans. The accuracy with which these scans were registered was assessed and a 3D model of the interior was created.


Author(s):  
Cosmin Popescu ◽  
Björn Täljsten ◽  
Thomas Blanksvärd ◽  
Gabriel Sas ◽  
Alexander Jimenez ◽  
...  

<p>Six railway bridges have been scanned using infrared scanning (IR), close range photogrammetry (CRP) and terrestrial laser scanning (TRS) to reconstruct point clouds and evaluate the potential of the technologies for building information modelling (BIM) and assessment purposes. The results may also help to improve bridge inspection routines. This is done by evaluating the accuracy and quality of the point clouds, time consumption, safety and traffic disturbance.</p><p>Wireless Monitoring has been used in a demonstration project in Sweden. It consists of a base station and nodes. The base station receives signals from the node antennas and transmits the signals to the cloud. The nodes are equipped with strain gauges, crack opening devices, temperature sensors or other suitable sensors for the investigation purpose. Results from the methods and conclusions regarding further use will be presented.</p>


2021 ◽  
Author(s):  
Ali Mirzazade ◽  
Cosmin Popescu ◽  
Thomas Blanksvärd ◽  
Björn Täljsten

<p>In bridge inspection, vertical displacement is a relevant parameter for both short and long-term health monitoring. Assessing change in deflections could also simplify the assessment work for inspectors. Recent developments in digital camera technology and photogrammetry software enables point cloud with colour information (RGB values) to be generated. Thus, close range photogrammetry offers the potential of monitoring big and small-scale damages by point clouds. The current paper aims to monitor geometrical deviations in Pahtajokk Bridge, Northern Sweden, using an optical data acquisition technique. The bridge in this study is scanned two times by almost one year a part. After point cloud generation the datasets were compared to detect geometrical deviations. First scanning was carried out by both close range photogrammetry (CRP) and terrestrial laser scanning (TLS), while second scanning was performed by CRP only. Analyzing the results has shown the potential of CRP in bridge inspection.</p>


2018 ◽  
Vol 35 ◽  
pp. 03002 ◽  
Author(s):  
Sławomir Porzucek ◽  
Monika Łój ◽  
Karolina Matwij ◽  
Wojciech Matwij

In the region of Siesławice (near Busko-Zdrój, Poland) there are unique phenomena of gypsum karst. Atmospheric factors caused numerous gypsum outcrops, canals and underground voids. The article presents the possibility of using non-invasive gravimetric surveys supplemented with geodetic measurements to illustrate karst changes occurring around the void. The use of modern geodetic measurement techniques including terrestrial and airborne laser scanning enables to generate a digital terrain model and a three-dimensional model of voids. Gravimetric field studies allowed to map the anomalies of the gravitational field of the near-surface zone. Geodetic measurement results have made it possible to accurately determine the terrain correction that supplemented the gravimetric anomaly information. Geophysical interpretation indicate the presence of weathered rocks in the near surface zone and fractures and loosened zones located surround the karst cave.


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