scholarly journals 3D IMAGE BASED GEOMETRIC DOCUMENTATION OF THE TOWER OF WINDS

2016 ◽  
Vol XLI-B5 ◽  
pp. 969-975 ◽  
Author(s):  
M. S. Tryfona ◽  
A. Georgopoulos
Keyword(s):  
Point Cloud ◽  
3D Model ◽  
Vertical Section ◽  
Three Dimensional ◽  
Horizontal Section ◽  
Extreme Caution ◽  
Cartesian Coordinate ◽  
Data Acquisition And Processing ◽  
Selection Of ◽  
At Will

This paper describes and investigates the implementation of almost entirely image based contemporary techniques for the three dimensional geometric documentation of the Tower of the Winds in Athens, which is a unique and very special monument of the Roman era. These techniques and related algorithms were implemented using a well-known piece of commercial software with extreme caution in the selection of the various parameters. Problems related to data acquisition and processing, but also to the algorithms and to the software implementation are identified and discussed. The resulting point cloud has been georeferenced, i.e. referenced to a local Cartesian coordinate system through minimum geodetic measurements, and subsequently the surface, i.e. the mesh was created and finally the three dimensional textured model was produced. In this way, the geometric documentation drawings, i.e. the horizontal section plans, the vertical section plans and the elevations, which include orthophotos of the monument, can be produced at will from that 3D model, for the complete geometric documentation. Finally, a 3D tour of the Tower of the Winds has also been created for a more integrated view of the monument. The results are presented and are evaluated for their completeness, efficiency, accuracy and ease of production.

scholarly journals 3D IMAGE BASED GEOMETRIC DOCUMENTATION OF THE TOWER OF WINDS

2016 ◽  
Vol XLI-B5 ◽  
pp. 969-975
Author(s):  
M. S. Tryfona ◽  
A. Georgopoulos
Keyword(s):  
Point Cloud ◽  
3D Model ◽  
Vertical Section ◽  
Three Dimensional ◽  
Horizontal Section ◽  
Extreme Caution ◽  
Cartesian Coordinate ◽  
Data Acquisition And Processing ◽  
Selection Of ◽  
At Will

This paper describes and investigates the implementation of almost entirely image based contemporary techniques for the three dimensional geometric documentation of the Tower of the Winds in Athens, which is a unique and very special monument of the Roman era. These techniques and related algorithms were implemented using a well-known piece of commercial software with extreme caution in the selection of the various parameters. Problems related to data acquisition and processing, but also to the algorithms and to the software implementation are identified and discussed. The resulting point cloud has been georeferenced, i.e. referenced to a local Cartesian coordinate system through minimum geodetic measurements, and subsequently the surface, i.e. the mesh was created and finally the three dimensional textured model was produced. In this way, the geometric documentation drawings, i.e. the horizontal section plans, the vertical section plans and the elevations, which include orthophotos of the monument, can be produced at will from that 3D model, for the complete geometric documentation. Finally, a 3D tour of the Tower of the Winds has also been created for a more integrated view of the monument. The results are presented and are evaluated for their completeness, efficiency, accuracy and ease of production.

scholarly journals Effect of the presence of orthodontic brackets on intraoral scans

2020 ◽  
Vol 91 (1) ◽  
pp. 98-104
Author(s):  
Sung-Ja Kang ◽  
Youn-Ju Kee ◽  
Kyungmin Clara Lee
Keyword(s):  
Cross Sections ◽  
Tooth Movement ◽  
Vertical Section ◽  
Three Dimensional ◽  
Orthodontic Brackets ◽  
Horizontal Section ◽  
Arch Width ◽  
Tooth Surfaces ◽  
The Cross ◽  
Width Measurements

ABSTRACT Objectives The need for intraoral scanning in the presence of brackets has increased for monitoring tooth movement during orthodontic treatment. The purpose of this study was to evaluate the effect of orthodontic brackets bonded to tooth surfaces on intraoral scans. Materials and Methods Intraoral scans were performed in 30 patients using both iTero and Trios scanners before and after bonding of the brackets. The two sets of intraoral scans of each patient and intraoral scans with and without brackets were superimposed using a best-fit algorithm, and three-dimensional (3D) surface analysis was performed. In each superimposition, discrepancies in the 3D axes and arch-width measurements in the incisor and molar regions were compared. In addition, the range of distortion around the brackets was evaluated on the cross sections of each superimposition. Results The overall discrepancies between the intraoral scans with and without brackets were within 0.30 mm. The arch-width discrepancies in the molar region were greater than those in the incisor region, but the differences were not statistically significant (P = .972 for iTero; P = .960 for Trios). The cross sections of the superimposed intraoral scans with and without brackets showed that the deviations were within 0.40 mm in the horizontal section and within 0.35 mm in the vertical section around the brackets. Conclusions The results of this study indicate that the accuracy of intraoral scans, even in the presence of brackets, is clinically acceptable, and the regions beyond 0.50 mm around the brackets should be used for superimposition on images without brackets.

Labview-Based Automatic Four-Axis Positioning Control Air Temperature and Wind Speed Detection Platform for Drying Oven

2013 ◽  
Vol 718-720 ◽  
pp. 1547-1553 ◽  
Author(s):  
Neng Sheng Bao ◽  
Shi Liang Fei ◽  
Xue Jia Huang ◽  
Tie Quan Liu ◽  
Jin Huang
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Software Design ◽  
Research Work ◽  
Three Dimensional ◽  
Theoretical Research ◽  
Positioning Control ◽  
Processing Data ◽  
Cartesian Coordinate ◽  
Data Acquisition And Processing

The design of domestic drying oven lacked theoretical basis and methods, especially a tool supporting experiments and verifying the results of theoretical research. This paper developed a platform, which can be used to automatically detect multi-point air temperature and wind speed from drying oven nozzle of printing and coating machines. The hardware design of platform achieves a four-axis positioning function by adopt a three-dimensional Cartesian coordinate robot and an additional servo motor. The LabVIEW-based software design of platform achieves many functions, including multi-axis positioning control, data acquisition and processing, data interface and operation interface. This platform contributes to research work for drying oven.

scholarly journals Reconstruction of an architectural object. Case study: Citadel fort No. 33 “Krakus” in Krakow

2018 ◽  
Vol 63 ◽  
pp. 00010
Author(s):  
Izabela Piech ◽  
Boguslawa Kwoczynska ◽  
Artur Ciszewski
Keyword(s):  
Point Cloud ◽  
3D Model ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Field Work ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Laser Measurements ◽  
The University

The aim of the study was to recreate, in the form of a 3D model, the Citadel fort No. 33 “Krakus” in Krakow. The data on the basis of which the three-dimensional model was made were obtained using a Leica ScanStation P40 terrestrial laser scanner, which is owned by the Faculty of Environmental Engineering and Geodesy of the University of Agriculture Hugona Kollataj in Krakow. The scope of field work included performing laser measurements, and then processing the point cloud in the Leica Cyclone 3D program and creating a full architectural model in SketchUp 2016.

scholarly journals Assessment of Tuff Sea Cliff Stability Integrating Geological Surveys and Remote Sensing. Case History from Ventotene Island (Southern Italy)

2020 ◽  
Vol 12 (12) ◽  
pp. 2006 ◽  
Author(s):  
Ruberti Daniela ◽  
Marino Ermanno ◽  
Pignalosa Antonio ◽  
Romano Pasquale ◽  
Vigliotti Marco
Keyword(s):  
3D Model ◽  
Risk Mitigation ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Fracture Network ◽  
Integrated Analysis ◽  
South Italy ◽  
The Stability ◽  
Data Acquisition And Processing ◽  
Sea Cliff

This study provides a detailed integrated analysis of the erosional processes affecting the volcanoclastic headlands of a pocket beach, of a typical Tyrrhenian volcanic island (Ventotene, south Italy). It compares the survey carried out in 2012 and the recent landslides that occurred in 2018–2020. The studied tuff cliff is characterised by steep, up to overhanging walls affected by a fracture network, which locally isolates blocks in precarious equilibrium. The stability conditions of the southern Cala Nave Bay sea cliff were evaluated by integrating a geological field survey, structural analysis of discontinuities, and a detailed topographic survey consisting of a terrestrial laser scanner (TLS) and photogrammetry data acquisition and processing, providing a three-dimensional (3D) model of the sea cliff. The 3D model of the area affected by the recent landslides was created using proximity photogrammetry, the Structure for Motion (SfM) methodology. The fracture network was represented by using high-resolution digital models and projected to realize geostructural vertical mapping of the cliff. The data acquired in 2012 were more recently compared with further surveys carried out, following rock failures that occurred in winter 2019–2020. The detachment planes and failure modalities coincide perfectly with the ones previously assessed. The applied techniques and the comparison with the recent rock failures have proven to be important in defining these conditions to address risk mitigation interventions.

scholarly journals 3D MODELING FOR ROCK ART DOCUMENTATION USING LIGHTWEIGHT MULTISPECTRAL CAMERA

2019 ◽  
Vol XLII-2/W9 ◽  
pp. 787-793 ◽  
Author(s):  
K. Zainuddin ◽  
Z. Majid ◽  
M. F. M. Ariff ◽  
K. M. Idris ◽  
M. A. Abbas ◽  
...  
Keyword(s):  
Point Cloud ◽  
3D Model ◽  
Rock Art ◽  
Three Dimensional ◽  
Laser Scanner ◽  
3D Point Cloud ◽  
Short Period ◽  
Dense Point ◽  
Close Range ◽  
Multispectral Camera

<p><strong>Abstract.</strong> This paper discusses the use of the lightweight multispectral camera to acquire three-dimensional data for rock art documentation application. The camera consists of five discrete bands, used for taking the motifs of the rock art paintings on a big structure of a cave based on the close-range photogrammetry technique. The captured images then processed using commercial structure-from-motion photogrammetry software, which automatically extracts the tie point. The extracted tie points were then used as input to generate a dense point cloud based on the multi-view stereo (MVS) and produced the multispectral 3D model, and orthophotos in a different wavelength. For comparison, the paintings and the wall surface also observed by using terrestrial laser scanner which capable of recording thousands of points in a short period of time with high accuracy. The cloud-to-cloud comparison between multispectral and TLS 3D point cloud show a sub-cm discrepancy, considering the used of the natural features as control target during 3D construction. Nevertheless, the processing also provides photorealistic orthophoto, indicates the advantages of the multispectral camera in generating dense 3D point cloud as TLS, photorealistic 3D model as RGB optic camera, and also with the multiwavelength output.</p>

scholarly journals Rail Track Detection and Projection-Based 3D Modeling from UAV Point Cloud

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5220
Author(s):  
Shima Sahebdivani ◽  
Hossein Arefi ◽  
Mehdi Maboudi
Keyword(s):  
3D Modeling ◽  
Point Cloud ◽  
3D Model ◽  
Three Dimensional ◽  
Point Clouds ◽  
Rail Track ◽  
Three Dimensional Modeling ◽  
Railway Industry ◽  
Dense Point ◽  
Uav Images

The expansion of the railway industry has increased the demand for the three-dimensional modeling of railway tracks. Due to the increasing development of UAV technology and its application advantages, in this research, the detection and 3D modeling of rail tracks are investigated using dense point clouds obtained from UAV images. Accordingly, a projection-based approach based on the overall direction of the rail track is proposed in order to generate a 3D model of the railway. In order to extract the railway lines, the height jump of points is evaluated in the neighborhood to select the candidate points of rail tracks. Then, using the RANSAC algorithm, line fitting on these candidate points is performed, and the final points related to the rail are identified. In the next step, the pre-specified rail piece model is fitted to the rail points through a projection-based process, and the orientation parameters of the model are determined. These parameters are later improved by fitting the Fourier curve, and finally a continuous 3D model for all of the rail tracks is created. The geometric distance of the final model from rail points is calculated in order to evaluate the modeling accuracy. Moreover, the performance of the proposed method is compared with another approach. A median distance of about 3 cm between the produced model and corresponding point cloud proves the high quality of the proposed 3D modeling algorithm in this study.

Comparative Study of 3D Model Transmission Strategies over Unreliable Network

2013 ◽  
Vol 846-847 ◽  
pp. 1826-1829
Author(s):  
Hao Ran Liu ◽  
Yan Huang
Keyword(s):  
Comparative Study ◽  
3D Model ◽  
Three Dimensional ◽  
Strong Support ◽  
Work Study ◽  
Computing Power ◽  
Advantages And Disadvantages ◽  
Starting Point ◽  
Three Dimensional Models ◽  
Selection Of

Three-dimensional models are being used in more and more applications. Although the ever increasing computing power of personal computers has been providing strong support to these applications, unreliable network is still a restricting factor, especially for mobile applications. As such, we in this work study several different broad strategies for 3D model transmission over unreliable network and comparatively analyze the advantages and disadvantages of each strategy. On one hand, this comparative study can guide the selection of an appropriate strategy for concrete applications; on the other, it provides a starting point for deeper investigation in robust and efficient 3D mesh transmission over unreliable network.

Handheld Laser Scanner Research

2019 ◽  
Vol 952 (10) ◽  
pp. 47-54
Author(s):  
A.V. Komissarov ◽  
A.V. Remizov ◽  
M.M. Shlyakhova ◽  
K.K. Yambaev
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Test Site ◽  
Optical Systems ◽  
Advantages And Disadvantages ◽  
Site Survey ◽  
Laser Scanners ◽  
Three Dimensional Models ◽  
The Stability

The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.

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