scholarly journals Terrestrial Laser Scanner for the Formal Assessment of a Roman-Medieval Structure—The Cloister of the Cathedral of Tarragona (Spain)

Geosciences ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 427
Author(s):  
Felipe Buill ◽  
M. Amparo Núñez-Andrés ◽  
Agustí Costa-Jover ◽  
David Moreno ◽  
Josep M. Puche ◽  
...  
Keyword(s):  
Point Cloud ◽  
Good Condition ◽  
Laser Scanner ◽  
3D Analysis ◽  
Terrestrial Laser Scanner ◽  
Analysis Methodology ◽  
General Terms ◽  
12Th Century ◽  
New Methodologies ◽  
Capture Techniques

The use of massive data capture techniques in architectural heritage has enhanced the development of new methodologies that have an important impact on their conservation and understanding. The research proposes the study of formal anomalies in the cloister of the Cathedral of Tarragona (c. 12th century). It is a relevant Gothic construction in Catalonia, with the special singularity that part of its structure is raised over an important pre-existing Roman wall. The investigation is based on a point cloud obtained with a terrestrial laser scanner (TLS) and the systematization of the 3D analysis methodology of the point cloud through different reference shapes. In general terms, the construction is in good condition, so the discrepancies between real construction and the shapes of reference are small, with some exceptions. Nevertheless, the different approximations used allowed us to identify some relevant features, such as the variability of the form of rib vaults, and the influence of the criteria used in the definition and location of reference forms.

scholarly journals Tank Modeling and Its Condition Assessment using Terrestrial Laser Scanner

2021 ◽  
Vol 936 (1) ◽  
pp. 012004
Author(s):  
Irwan Gumilar ◽  
Samuel Van Livtrik Lumban Gaol ◽  
Made Munarda ◽  
Brian Bramanto ◽  
Agus Lukmanulhakim
Keyword(s):  
Data Processing ◽  
Point Cloud ◽  
Good Condition ◽  
Laser Scanner ◽  
Condition Assessment ◽  
American Petroleum Institute ◽  
Terrestrial Laser Scanner ◽  
Cloud Data ◽  
Data Assessment ◽  
The Difference

Abstract Condition assessment of the tank must be carried out since it is related to Health, Safety, and Environment (HSE). Assessment is carried out by referring to the applicable standards. This study aims to create a 3D (Dimension) model and assess the tank using Terrestrial Laser Scanner technology. This includes planning, data acquisition, data processing, and data visualization. The data processing process starts with the registration stage with the cloud-to-cloud method, georeferencing, 3D modeling using point cloud, and tank assessment filtered point cloud data. Assessment includes analysis of volume, verticality/slope (in terms of the difference between upper and lower tank), and roundness calculations. The 3D model of the tank was generated with a registration error of less than 1 cm. The volume of tank I and tank II were calculated to 134.108 m3 and 134.067 m3, respectively. The difference between the upper and lower radius for each tank ranges from 2 to 10 mm. Considering the results and recalling the API 650 standard (American Petroleum Institute), each tank is considered reliable and in a good condition.

scholarly journals Fitting Terrestrial Laser Scanner Point Clouds with T-Splines: Local Refinement Strategy for Rigid Body Motion

2021 ◽  
Vol 13 (13) ◽  
pp. 2494
Author(s):  
Gaël Kermarrec ◽  
Niklas Schild ◽  
Jan Hartmann
Keyword(s):  
Point Cloud ◽  
Goodness Of Fit ◽  
Laser Scanner ◽  
Point Clouds ◽  
Statistical Testing ◽  
Computational Time ◽  
Terrestrial Laser Scanner ◽  
Reference Surface ◽  
Local Refinement ◽  
Surface Approximation

T-splines have recently been introduced to represent objects of arbitrary shapes using a smaller number of control points than the conventional non-uniform rational B-splines (NURBS) or B-spline representatizons in computer-aided design, computer graphics and reverse engineering. They are flexible in representing complex surface shapes and economic in terms of parameters as they enable local refinement. This property is a great advantage when dense, scattered and noisy point clouds are approximated using least squares fitting, such as those from a terrestrial laser scanner (TLS). Unfortunately, when it comes to assessing the goodness of fit of the surface approximation with a real dataset, only a noisy point cloud can be approximated: (i) a low root mean squared error (RMSE) can be linked with an overfitting, i.e., a fitting of the noise, and should be correspondingly avoided, and (ii) a high RMSE is synonymous with a lack of details. To address the challenge of judging the approximation, the reference surface should be entirely known: this can be solved by printing a mathematically defined T-splines reference surface in three dimensions (3D) and modeling the artefacts induced by the 3D printing. Once scanned under different configurations, it is possible to assess the goodness of fit of the approximation for a noisy and potentially gappy point cloud and compare it with the traditional but less flexible NURBS. The advantages of T-splines local refinement open the door for further applications within a geodetic context such as rigorous statistical testing of deformation. Two different scans from a slightly deformed object were approximated; we found that more than 40% of the computational time could be saved without affecting the goodness of fit of the surface approximation by using the same mesh for the two epochs.

scholarly journals Comparison of Depth Camera and Terrestrial Laser Scanner in Monitoring Structural Deflections

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 201
Author(s):  
Michael Bekele Maru ◽  
Donghwan Lee ◽  
Kassahun Demissie Tola ◽  
Seunghee Park
Keyword(s):  
Optical Sensors ◽  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Point Clouds ◽  
Depth Camera ◽  
Terrestrial Laser Scanner ◽  
Cloud Data ◽  
3D Point Clouds ◽  
3D Information

Modeling a structure in the virtual world using three-dimensional (3D) information enhances our understanding, while also aiding in the visualization, of how a structure reacts to any disturbance. Generally, 3D point clouds are used for determining structural behavioral changes. Light detection and ranging (LiDAR) is one of the crucial ways by which a 3D point cloud dataset can be generated. Additionally, 3D cameras are commonly used to develop a point cloud containing many points on the external surface of an object around it. The main objective of this study was to compare the performance of optical sensors, namely a depth camera (DC) and terrestrial laser scanner (TLS) in estimating structural deflection. We also utilized bilateral filtering techniques, which are commonly used in image processing, on the point cloud data for enhancing their accuracy and increasing the application prospects of these sensors in structure health monitoring. The results from these sensors were validated by comparing them with the outputs from a linear variable differential transformer sensor, which was mounted on the beam during an indoor experiment. The results showed that the datasets obtained from both the sensors were acceptable for nominal deflections of 3 mm and above because the error range was less than ±10%. However, the result obtained from the TLS were better than those obtained from the DC.

scholarly journals Interactive Trunk Extraction from Forest Point Cloud

2014 ◽  
Vol XL-5 ◽  
pp. 433-436
Author(s):  
T. Mizoguchi ◽  
Y. Kobayashi
Keyword(s):  
Forest Management ◽  
Point Cloud ◽  
Laser Scanner ◽  
Interactive System ◽  
Terrestrial Laser Scanner ◽  
Diameter At Breast Height ◽  
Breast Height

For forest management or monitoring, it is required to constantly measure several parameters of each tree, such as height, diameter at breast height, and trunk volume. Terrestrial laser scanner has been used for this purpose instead of human workers to reduce time and cost for the measurement. In order to use point cloud captured by terrestrial laser scanner in the above applications, it is an important step to extract all trees or their trunks separately. For this purpose, we propose an interactive system in which a user can intuitively and efficiently extract each trunk by a simple editing on the distance image created from the point cloud. We demonstrate the effectiveness of our proposed system from various experiments.

scholarly journals Accuracy Analysis Of Three Dimensional Models Of Building Prof. H. Soedarto S. H. Using The Terrestrial Laser Scanner Technology Based On Traverse Method

Teknik ◽  
2019 ◽  
Vol 39 (2) ◽  
pp. 94
Author(s):  
Yudo Prasetyo
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Terrestrial Laser Scanner ◽  
Accuracy Analysis ◽  
Dimensional Models ◽  
Data Point ◽  
Three Dimensional Models

Teknologi dokumentasi gedung secara spasial untuk konservasi dan perencanaan tata ruang semakin berkembang pesat. Urgensi tingkat ketelitian dalam suatu pengukuran juga dituntut semakin tinggi. Salah satu teknologi pembentukan objek tiga dimensi yang berkembang saat ini adalah Terrestrial Laser Scanner (TLS). Metode pengukuran TLS terdiri atas 4 metode yaitu: Cloud to Cloud, Target to Target, Traverse, dan metode kombinasi. Penelitian ini bertujuan untuk menganalisa tingkat ketelitian metode Traverse dalam pengukuran suatu objek model tiga dimensi untuk keperluan dokumentasi gedung menggunakan TLS.Ketelitian metode Traverse akan diujikan pada Gedung Prof. H. Soedarto, S. H. Tingkat ketelitiannya diujikan pada dua parameter yakni hasil metode registrasi dan hasil visualisasi model tiga dimensi. Hasil analisis pengolahan data point cloud menunjukkan bahwa alat TLS dengan metode Traverse dapat digunakan untuk menghasilkan model tiga dimensi Gedung Prof. Sudarto, S. H. Nilai rata-rata validasi yang diperoleh adalah sebesar 0,004 meter dengan besaran ketelitian model RMSE sebesar ±0,00611 meter. 

Virtual Modelling of Prehistoric Sites and Artefacts by Automatic Point-Cloud Surveys

2011 ◽  
pp. 201-217
Author(s):  
Mercedes Farjas ◽  
Francisco J. García-Lázaro ◽  
Julio Zancajo ◽  
Teresa Mostaza ◽  
Nieves Quesada
Keyword(s):  
Initial Data ◽  
Research Group ◽  
Point Cloud ◽  
Laser Scanner ◽  
New Method ◽  
Surface Model ◽  
Digital Surface Model ◽  
Automatic Data ◽  
Operational Costs ◽  
New Methodologies

This chapter presents laser scanner systems as a new method of automatic data acquisition for use in archaeological research. The operation of the equipment is briefly described and results are presented from its application in two Spanish archaelogical sites: Abrigo de Buendía (Cuenca), Atapuerca (Burgos). Together with these systems, point cloud measuring photogrammetric methods are revised. Photogrammetry has been widely used in heritage documentation and in no way is to be relegated by the new scanning techniques. Instead, Photogrammetry upgrades its methods by applying digital approaches so that it becomes competitive in both, operational costs and results. Nevertheless, Photogrammetry and laser scanner systems should be regarded as complementary rather than competing techniques. To illustrate photogrammetric methods their application to generate the Digital Surface Model of an epigraph is described. The authors’ research group endeavours to combine teaching and research in its different fields of activity. Initial data are acquired in project-based teaching situations and international seminars or other activities. Students thus have the opportunity to become familiar with new methodologies while collecting material for analytical studies.

Structure Deformation Measurement with Terrestrial Laser Scanner at Pathein Bridge in Myanmar

2018 ◽  
Vol 13 (1) ◽  
pp. 40-49 ◽  
Author(s):  
Nuntikorn Kitratporn ◽  
◽  
Wataru Takeuchi ◽  
Koji Matsumoto ◽  
Kohei Nagai
Keyword(s):  
Point Cloud ◽  
Cloud Model ◽  
Laser Scanner ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Terrestrial Laser Scanner ◽  
Bridge Structure ◽  
Surface Geometry ◽  
Deformation State ◽  
Measurement Results

In Myanmar, defects and possible deformation were reported in many long-span suspension bridges. The current state of bridge infrastructure must be inspected, so that deterioration can be stalled and failure can be prevented. A 3D laser scanner, specifically the terrestrial laser scanner (TLS), has demonstrated the ability to capture surface geometry with millimeter accuracy. Consequently, TLS technology has received significant interest in various applications including in the field of structural survey. However, research on its application in large bridge structure remains limited. This study examines the use of TLS point cloud for the measurement of three deformation behaviors at the Pathein Suspension Bridge in Myanmar. These behaviors include tower inclination, hanger inclination, and deflection of bridge truss. The measurement results clearly captured the deformation state of the bridge. A comparison of the measurement results with available conventional measurements yielded overall agreement. However, errors were observed in some areas, which could be due to noise and occlusion in the point cloud model. In this study, the advantages of TLS in providing non-discrete data, direct measurement in meaningful unit, and access to difficult-to-access sections, such as top of towers or main cables, were demonstrated. The limitations of TLS as observed in this study were mainly influenced by external factors during field survey. Hence, it was suggested that further study on appropriate TLS surveying practice for large bridge structure should be conducted.

scholarly journals An Automatic Tree Skeleton Extracting Method Based on Point Cloud of Terrestrial Laser Scanner

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ronghao Li ◽  
Guochao Bu ◽  
Pei Wang
Keyword(s):  
Topological Structure ◽  
Point Cloud ◽  
Laser Scanner ◽  
High Accuracy ◽  
Terrestrial Laser Scanner ◽  
Peach Tree ◽  
Point Cloud Data ◽  
Breadth First Search ◽  
Cloud Data ◽  
Real Tree

Tree skeleton could describe the shape and topological structure of a tree, which are useful to forest researchers. Terrestrial laser scanner (TLS) can scan trees with high accuracy and speed to acquire the point cloud data, which could be used to extract tree skeletons. An adaptive extracting method of tree skeleton based on the point cloud data of TLS was proposed in this paper. The point cloud data were segmented by artificial filtration and k-means clustering, and the point cloud data of trunk and branches remained to extract skeleton. Then the skeleton nodes were calculated by using breadth first search (BFS) method, quantifying method, and clustering method. Based on their connectivity, the skeleton nodes were connected to generate the tree skeleton, which would be smoothed by using Laplace smoothing method. In this paper, the point cloud data of a toona tree and peach tree were used to test the proposed method and for comparing the proposed method with the shortest path method to illustrate the robustness and superiority of the method. The experimental results showed that the shape of tree skeleton extracted was consistent with the real tree, which showed the method proposed in the paper is effective and feasible.

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