scholarly journals Correlations Between Aggregate Particle Shape Parameters and Size Based on Images Captured Using a 3-D Laser Scanning Device

2014 ◽  
Vol 15 (2) ◽  
pp. 27-36 ◽  
Author(s):  
Martin B. Mgangira ◽  
Julius Komba
Keyword(s):  
Particle Shape ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Free Form ◽  
Shape Parameters ◽  
Aggregate Particle ◽  
Laser Scanners ◽  
Aggregate Shape ◽  
Ideal Technique

Abstract Three dimensional (3-D) laser scanning has recently proved to be an ideal technique for quantifying aggregate particle shape parameters. This is because 3-D laser scanners measure fine details and capture free-form shapes. This paper presents some results of an on-going study, which utilises 3-D laser scanning technology to quantify aggregate shape parameters. Specific correlations and shape parameters have been considered. The results have shown that meaningful correlations exist between 3-D sphericity and aspect ratio as well as between specific surface area and the particle diameter as defined in this paper. The results of the current study are consistent with generally accepted relationships between shape parameters and particle size, further validating the application of the 3-D laser scanning technology

The Advantages of Using Laser Scanners in Surveying in Protected Sites

2015 ◽  
pp. 382-402
Author(s):  
Gülhan Benli
Keyword(s):  
Protected Areas ◽  
Point Cloud ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
Point Cloud Data ◽  
Cloud Data ◽  
Laser Scanners ◽  
Point Data

Since the 2000s, terrestrial laser scanning, as one of the methods used to document historical edifices in protected areas, has taken on greater importance because it mitigates the difficulties associated with working on large areas and saves time while also making it possible to better understand all the particularities of the area. Through this technology, comprehensive point data (point clouds) about the surface of an object can be generated in a highly accurate three-dimensional manner. Furthermore, with the proper software this three-dimensional point cloud data can be transformed into three-dimensional rendering/mapping/modeling and quantitative orthophotographs. In this chapter, the study will present the results of terrestrial laser scanning and surveying which was used to obtain three-dimensional point clouds through three-dimensional survey measurements and scans of silhouettes of streets in Fatih in Historic Peninsula in Istanbul, which were then transposed into survey images and drawings. The study will also cite examples of the facade mapping using terrestrial laser scanning data in Istanbul Historic Peninsula Project.

Digital Measurement and its Error Analysis for the Machining Free-Form Surface

2014 ◽  
Vol 664 ◽  
pp. 263-267
Author(s):  
Feng Lu ◽  
Ning Li ◽  
Xiao Fei Zhang
Keyword(s):  
Laser Scanning ◽  
Optical Measurement ◽  
Three Dimensional ◽  
Point Clouds ◽  
Free Form ◽  
Digital Measurement ◽  
Machining Errors ◽  
Three Dimensional Measurement ◽  
Free Form Surface ◽  
Free Form Surfaces

To deal with the lack of accurate and efficient inspection methods in complex free-form surfaces, three-dimensional measurement method based on the optical measurement and computer image processing technology was proposed. It adopted laser scanning technology to get point clouds of free-form surface. Used rapid measurement software to inspect precision of point cloud& CAD model. What could be the cause of machining errors was analyzed. 3D deviation inspection of complex surfaces was applied by an artifact. Detected the machining error of an important section, and outputted test report. This research provides a convenient and swift method for the inspection of free-form surface and processing quality control.

scholarly journals Testing as-Built Quality of Free-Form Panels: Lessons Learned from a Case Study and Mock-up Panel Tests

2021 ◽  
Vol 11 (4) ◽  
pp. 1439
Author(s):  
Jong-Ho Ock
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Lessons Learned ◽  
Fiber Reinforced Concrete ◽  
Free Form ◽  
Geometric Difference ◽  
Curved Panel ◽  
Curved Panels

Constructing free-form buildings is very complex due to the difficulty in fabricating the curved façade. To install the façade, the complex geometric shapes of the façade need to be divided into panels. The panels developed are classified into three categories in terms of their curvatures, i.e., planar, single-curved, double-curved panels. The quality of the curved façade is determined by the geometric difference between as-built and as-designed panel shapes. Among the three types of curved panels, the double-curved panel is very difficult to form, showing greater quality discrepancy than the other two panel types. Ensuring the as-built quality of the curved façade is for contractors. The main objective of this study is to enhance small/mid-size contractors’ capacity of managing the as-built quality of the double-curved panel. To meet the study objectives, a case study of a small free-form building and empirical mock-up tests of curved panels were performed and beneficial lessons for the contractors were identified through the tests. Among diverse materials, aluminum and glass-fiber-reinforced concrete (GFRC) were utilized for the mock-up tests. Three-dimensional laser scanning technology was employed to foster the as-built data of the case study project and the mocked-up double-curved panels. The data superimposition method was used to measure the deviation between the as-designed and the as-built data of the case study.

scholarly journals Development and validation of wear models by using innovative three-dimensional laser scanners

2019 ◽  
Vol 11 (8) ◽  
pp. 168781401987040 ◽  
Author(s):  
E Butini ◽  
L Marini ◽  
E Meli ◽  
A Rindi ◽  
MC Valigi ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Research Work ◽  
Three Dimensional ◽  
Measuring Instruments ◽  
Test Case ◽  
Shape Variation ◽  
Measurement Systems ◽  
Laser Scanners ◽  
Development And Validation ◽  
The City

One of the main problems in railway and tramway systems, both dynamically (safety, comfort etc.) and economically (planning of maintenance interventions, reduction of wheel and rail lifetime etc.), is represented by the wear of wheel and rail profiles, due to the wheel–rail interaction. The profile’s shape variation caused by wear influences the dynamic behaviour of the vehicle and, in particular, the wheel–rail contact conditions. Hence, nowadays, one of the most important topics in the railway field is the development of reliable wear models to predict profiles evolution, together with the use of more efficient and accurate measuring instruments for the model validation and the rolling components inspection. In this context, the aim of this research work is the development and the validation of wear models, using experimental data acquired through an innovative measuring instrument based on noncontact three-dimensional laser scanning technology. The tramway line of the city of Florence, characterized by very narrow curves and critical in terms of wear, has been chosen as a reference test case. Moreover, the inspection procedures currently adopted on this line for the maintenance plan are based only on classical two-dimensional contact measurement systems, not so accurate for a complete wear assessment. Therefore, the introduction of a new three-dimensional laser scanning technology may have a great impact on the maintenance management of the line.

scholarly journals THREE-DIMENSIONAL RECORDING AND PHOTOREALISTIC MODEL RECONSTRUCTION FOR VIRTUAL MUSEUM APPLICATION – AN EXPERIENCE IN MALAYSIA

2019 ◽  
Vol XLII-2/W9 ◽  
pp. 763-771
Author(s):  
O. C. Wei ◽  
Z. Majid ◽  
H. Setan ◽  
M. F. M. Ariff ◽  
K. M. Idris ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Tourism Industry ◽  
Digital Recording ◽  
Virtual Museum ◽  
Heritage Sites ◽  
Range Type ◽  
Laser Scanners ◽  
Close Range

<p><strong>Abstract.</strong> In recent years, museums are utilizing the ability of virtual reality (VR) technologies to visualize their collections in three-dimensional (3D) environment. The demands for 3D digitization of cultural heritage have increase greatly to facilitate the development of virtual museum. Among the available techniques, the use of laser scanning for digital recording and 3D reproduction of the heritage sites and archaeological artefacts are technically more reliable due to its rapid and high resolution data capture. However, the suitable 3D laser scanners used greatly depend on the level of details and size of an object. This research used medium and close-range type of laser scanners to digitally record the heritage objects. The aim of this research was to develop methodology framework for digital recording and 3D reproduction of archaeological artefact and heritage sites in Malaysia by using terrestrial laser scanning technology. Besides, this research focused on the reconstruction of photorealistic 3D models based on the colour information yield by close-range photogrammetry. The colour descriptions were obtained either by built-in camera or externally integrated camera on the laser scanner. For better colour descriptions, external images were captured by independent Nikon D300s digital camera. The geometric model accuracy of A’Famosa and terracotta Buddha statuette was in 5<span class="thinspace"></span>mm and 0.41<span class="thinspace"></span>mm respectively. 3D <i>flythrough</i> animation was rendered by using the coloured point clouds model. The development of 3D Virtual Walkthrough Museum (3DVWM) utilized the 3D PDF document and SCENE WebShare platform to offer realistic visualization experience to the visitors where the reality-based models could be manipulate in 3D geometric aspects and use of metric analysis. Thus, 3DVWM can facilitate the virtual museum application in Malaysia and enable wider visitors to virtually appreciate the cultural heritage in Malaysia. Thus, this indirectly stimulates the tourism industry in our country.</p>

Reverse Engineering of Quadric Surfaces Employing Three-Dimensional Laser Scanning

1994 ◽  
Vol 208 (1) ◽  
pp. 21-28 ◽  
Author(s):  
C Bradley ◽  
G W Vickers ◽  
M Milroy
Keyword(s):  
Reverse Engineering ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Coordinate Measuring Machine ◽  
Complex Surface ◽  
Free Form ◽  
Surface Patches ◽  
Measuring Machine ◽  
Free Form Surfaces

A software package for the reverse engineering of surface forms commonly found in manufactured objects is presented. An object's surface is digitized using a three-dimensional, laser-based scanner that produces accurate and copious data files. Complex surface forms are reconstructed by interactively segmenting the multiple-surface patches, invoking the appropriate surface modelling routine and transferring the resulting surfaces to a CAD package via a standard IGES entity. Examples of the accuracy of the laser scanner data, and software algorithms for modelling planes, cylinders, cones and spheres, are presented by performing comparisons with results generated by a coordinate measuring machine. The paper concentrates on the novel software process to model the principal quadric forms; however, the program's capabilities do extend to free-form surfaces.

scholarly journals Integration Of Three Dimensional Data From Unkown Origin On the Example Of A Traditional Residential Building In Al-Balad, Jeddah, Saudi Arabia

2014 ◽  
Vol II-5 ◽  
pp. 161-165
Author(s):  
U. Herbig ◽  
I. Mayer ◽  
H. Mortada ◽  
S. Rasztovits
Keyword(s):  
Saudi Arabia ◽  
Laser Scanning ◽  
Standard Procedure ◽  
Three Dimensional ◽  
Residential Building ◽  
Traditional Architecture ◽  
University Of Technology ◽  
Laser Scanners ◽  
Scan Data

3D Laser scanning technology gained more and more importance for the recording and documentation of architectural heritage. Especially for the survey of heterogeneous surfaces and complex structures it is a fast and reliable option for survey and so appreciated sources for research in architecture. Therefore the integration of laser scanning as a part of the building survey became a kind of standard procedure for objects of different scale, shape, age and origin. <br><br> In some cases more than one team records an object with different devices using altering approaches. For example a client provides existing data from a part of the object that can't be accessed anymore, but is important to be integrated into the overall survey. The merging of the datasets may become challenging, especially if one survey is not documented in detail, in particular when it comes to the quality of the result. <br><br> For a research about the traditional architecture of Saudi Arabia a building in the historic part of Jeddah has been surveyed in detail by a team of researchers of the Vienna University of Technology. Within this frame a workshop for students of the King Abdul Aziz about building archaeological research has been conducted. As part of the results consists of two sets of laserscan data, recorded with different laser scanners. Using these data a possible approach for the registration of scan data from different and/or unknown provenance has been developed which will be outlined in this paper.

Local Least Squares Fitting for Surface Mesh Fairing in Automobile Panel Design

2002 ◽  
Author(s):  
Miguel Vieira ◽  
Kenji Shimada ◽  
Tomotake Furuhata
Keyword(s):  
Least Squares ◽  
Constant Curvature ◽  
Computer Aided Design ◽  
Laser Scanning ◽  
Linear Time ◽  
Local Coordinate System ◽  
Three Dimensional ◽  
Laser Scanners ◽  
Automobile Panel ◽  
Aided Design

Three-dimensional laser scanning equipment is being used more frequently to convert clay model automobile designs to large, detailed meshes for computer-aided design of outer-body panels. The panels are generally composed of large, constant curvature patches with small local features, called character lines, superposed to give the car a distinctive look. Although modern laser scanners are very accurate and precise, their tolerances nevertheless admit meshes with geometric flaws that destroy the constant curvature of patches and make character lines nearly invisible in a reflection simulation. Thus, we require an algorithm to fair the mesh by restoring the intended curvature while minimizing the vertex displacemtents. Existing approaches such as Laplacian and curvature flow operators are not suitable because they tend to shrink the mesh and introduce a bias toward planar geometries. Our approach aims to solve both of these problems by fitting a least squares surface to a set of vertices adjacent to the target vertex and moving the target vertex vertically onto the least squares surface in a local coordinate system. This algorithm has linear time complexity in the number of vertices and makes convergence likely while eliminating the planar bias of other operators. We show the effectiveness of our operator with both geometric and real-world mesh examples.

scholarly journals UNDERSTANDING THE EFFECTS OF DOCUMENTATION DETAIL ON DIAGNOSTICS OF HISTORIC STRUCTURES

2019 ◽  
Vol XLII-2/W15 ◽  
pp. 843-848
Author(s):  
R. K. Napolitano ◽  
M. Hess ◽  
B. Glisic
Keyword(s):  
Laser Scanning ◽  
Distinct Element ◽  
Three Dimensional ◽  
Level Of Detail ◽  
Laser Scanners ◽  
Historic Structures ◽  
New Construction ◽  
Distinct Element Modelling ◽  
Three Dimensional Models

<p><strong>Abstract.</strong> Before reinforcements or new construction are added to historic structures, it is important to understand how the existing damage could have arisen. Often to do this, documentation methods such as laser scanning and photogrammetry are used to capture the existing conditions and physics-based models are used to simulate the response of a facsimile structure to various responses. Something that varies quite a bit though is the level of detail used to capture the existing conditions as well as the level of detail used to represent the structure during physics-based modelling. This paper aims to understand the effects of documentation detail on diagnostics of historic structures. To do this, two masonry structures were documented with laser scanners, photographs, and thermal images. For each case study, three-dimensional models of varying fidelity were generated based on the results of simulation. The response of these models to loading conditions was then calculated using a physics-based modelling technique called finite-distinct element modelling. The results for each case study are compared to understand the impacts of geometry on diagnostics; discussion about future tools to augment current practices is included.</p>

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