scholarly journals Analysis of hyperboloid cooling tower projection on 2D shape

2021 ◽  
Vol 3 ◽  
pp. 25-40
Author(s):  
Andrzej Kwinta ◽  
◽  
Joanna Bac-Bronowicz ◽  
Keyword(s):  
Laser Scanning ◽  
Cooling Tower ◽  
Side Surface ◽  
Outer Wall ◽  
Single Plane ◽  
Popular Method ◽  
Conical Projection ◽  
Geometric Data ◽  
Cylindrical Projection

This paper undertakes the problem of mapping a hyperboloid cooling tower on a single plane. Measurements performed by ground-based laser scanning technology quickly deliver substantial amounts of geometric data of the tower’s outer wall. The essence of the article is projection of the rotational hyperboloid on a plane. The shape of the hyperboloid cooling tower is not directly expandable to a single plane. Mapping a hyperboloid shape on a plane is, therefore, associated with distortions. This paper presents a comparison between cylindrical and conic projection of a hyperboloid cooling tower. The most popular method of mapping hyperboloid is cylindrical projection. The cylinder’s side surface is easily developed on the drawing sheet. For the hyperboloid cooling tower, the biggest distortions occur in the latitudinal direction and reach the highest values at the top and bottom edges. The equation (13) describe distortion for the cylindrical projection. The equation (18) describe distortion for the conical projection. This paper presents results obtained from the performed measurement. The analysis found that cone mapping produces less distortion than cylindrical projection for the hyperboloid cooling tower. We think, that in conical projection, the shape of a hyperboloid cooling tower and theoretical conic shape have better corresponding together than in cylindrical projection.

scholarly journals Assessment of the Shear Strength of Pile-to-Soil Interfaces Based on Pile Surface Topography Using Laser Scanning

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1012 ◽  
Author(s):  
Zbigniew Muszyński ◽  
Marek Wyjadłowski
Keyword(s):  
Shear Strength ◽  
Surface Topography ◽  
Friction Factor ◽  
Laser Scanning ◽  
Least Squares Method ◽  
Soil Layer ◽  
Side Surface ◽  
Sample Height ◽  
Functional Volume

This article presents in situ research on the side surface of continuous flight auger (CFA) foundation piles using a three-dimensional (3D) laser scanner (Leica ScanStation C10) in order to evaluate the morphology assessment of pile concrete surfaces in various geotechnical layers. Terrestrial laser scanning describes the 3D geometry of the construction with high spatial resolution and accuracy. A total of six areas were selected from the acquired point cloud for which a two-step approach for removing the form was applied. In the first step, the reference surface was fitted using the least squares method, and then, cylindrical projection of the surface was performed. In the second step, an operator of removal of the multi-plane form was applied. For each sample, height parameters (Sq, Ssk, Sku, Sp, Sv, Sz, Sa) and functional volume parameters (Vmp, Vmc, Vvc, Vvv) according to the standard ISO 25178-2:2012 were determined. Significant differences in the values of surface height and functional volume parameters were observed for each geotechnical layer where piles were formed. Because the piles remain embedded in the ground, in situ tests of the side surface of piles are rarely performed and taken into account in the assessment of pile bearing capacity. The study of surface topography is a crucial stage in the assessment of the shear strength at the interface between a concrete pile and the soil layer. The obtained concrete morphology assessments are applicable during the determination of the skin friction factor in the analytical or numerical estimation of pile shaft resistance. The proposed procedure of morphology evaluation may improve the fidelity of the assumed friction factor between the concrete and soil and increase the reliability of direct shear experiments.

scholarly journals Brama zamku „Golesz” w Krajowicach w świetle badań archeologicznych i prac zabezpieczająco-restauratorskich prowadzonych w latach 2010–2019

2020 ◽  
Vol 41 ◽  
pp. 127-158
Author(s):  
Antoni Lubelczyk ◽  
Keyword(s):  
Laser Scanning ◽  
Outer Wall ◽  
Archaeological Research ◽  
3D Laser Scanning ◽  
Modern Period ◽  
Degenerate Form ◽  
Gate System ◽  
The Subject ◽  
The Right

The subject of the article is a gate of the medieval and modern period castle “Golesz” in the former Sandomierz land. First of all, there is a description of the gate as the only element of the castle that survived on the surface in a degenerate form and was described in this form at the turn of the 19th and 20th centuries. Later, the results of archaeological research and conservation work carried out in 2010–2019 have been presented. A gate system (12×10 m) was recognized, with a thickened section housing two small rooms on the right, a 4-meter-wide passageway in the centre and an outer wall with a buttress on the left. The exposed walls were secured and left in the form of a permanent ruin. Both stages of work at the site have been thoroughly documented on the basis of 3D laser scanning technologies.

A framework for in-situ geometric data acquisition using laser scanning for BIM modelling

2020 ◽  
Vol 28 ◽  
pp. 101073 ◽  
Author(s):  
Luís Sanhudo ◽  
Nuno M.M. Ramos ◽  
João Poças Martins ◽  
Ricardo M.S.F. Almeida ◽  
Eva Barreira ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Laser Scanning ◽  
Geometric Data

scholarly journals An automatic shoe-groove feature extraction method based on robot and structural laser scanning

2016 ◽  
Vol 14 (1) ◽  
pp. 172988141667813 ◽  
Author(s):  
Xiaojun Wu ◽  
Zefei Li ◽  
Peizhi Wen
Keyword(s):  
Feature Extraction ◽  
Laser Scanning ◽  
Dimensional Space ◽  
Industrial Robot ◽  
Three Dimensional ◽  
Side Surface ◽  
Three Dimension ◽  
Two Dimensional ◽  
Feature Extraction Method ◽  
Shoe Manufacturing

In order to improve the operational efficiency of robot-based shoe manufacturing, a method of shoe-groove tracking based on industrial robot is presented in the article. First, side surface of a shoe upper with a sole is scanned with a laser scanning device. The presented approach mainly consists of two steps: reconstruction of three-dimensional point cloud and feature curve extraction. It is difficult to extract the closed groove curve on shoe surface. We propose an innovative method to simplify the feature extraction through projecting geometric information from three dimension to two dimension, which is convenient to identify longest groove feature line in two-dimensional space. After detecting the two-dimensional groove line, we back project it to three-dimensional space to identify the three-dimensional thick groove point set. Finally, we thin and fit the groove curve into a trackable sequential curve. The experimental results show that the proposed system can effectively detect the shoe groove and generate trackable sequential curve. We also simulate the robot tracking process in a virtual environment to demonstrate the effectiveness of the presented method.

scholarly journals THE FLORENCE BAPTISTERY: 3-D SURVEY AS A KNOWLEDGE TOOL FOR HISTORICAL AND STRUCTURAL INVESTIGATIONS

2016 ◽  
Vol XLI-B5 ◽  
pp. 977-984 ◽  
Author(s):  
G. Tucci ◽  
V. Bonora ◽  
L. Fiorini ◽  
A. Conti
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Outer Wall ◽  
Structural Investigations ◽  
Survey Techniques ◽  
Wide Range ◽  
Historical Architecture ◽  
Close Range ◽  
Main Instrument ◽  
New Research

The Baptistery of San Giovanni is one of the most important pieces of architecture in Florence. It is an octagonal building, encrusted with marble both internally and externally (including the pyramidal roof) and covered inside by a magnificent dome with sparkling gold mosaics. During Dante’s time, it appeared much older than the other monuments, so its origins were considered as hailing straight from Florence’s most remote and mythical history. Even though we have much more data now, scholars still disagree over the interpretations on the origin and construction sequence of the monument. <br><br> Survey has always been considered a main instrument for understanding historical architecture, mostly from constructional and structural points of view. During the last century, the Baptistery was surveyed using both traditional techniques and the most up-to-date instruments available at the time, such as topography, close-range photogrammetry and laser scanning. So, a review of those early applications, even if partial or isolated, can significantly attest to the state of the art and evolution of survey techniques. <br><br> During recent years, the Opera di Santa Maria del Fiore promoted new research and a wide range of diagnostic investigations aimed at acquiring greater knowledge of the monument in anticipation of the cleaning and restoration of the outer wall surfaces during 2015. <br><br> Among this research, GeCo Lab carried out a new systematic and complete laser scanner survey of the whole Baptistery, acquiring data for the more inaccessible parts that were given little attention during other survey campaigns. <br><br> First of all, the paper analyses recent contributions given by instrumental surveys in advancing knowledge of the building, with references to the cutting-edge techniques and measurement tools used at the time. Then, it describes the new survey campaign, illustrating the approach followed in the planning, data acquisition and data elaboration phases; finally, it gives examples of some interpretations of the structure stemming from the new acquisitions.

scholarly journals Measurement point density and measurement methods in determining the geometric imperfections of shell surfaces

2018 ◽  
Vol 105 (1) ◽  
pp. 19-28
Author(s):  
Rafał Kocierz ◽  
Michał Rębisz ◽  
Łukasz Ortyl
Keyword(s):  
Laser Scanning ◽  
Cooling Tower ◽  
Optimal Number ◽  
Cooling Towers ◽  
Geometric Imperfections ◽  
Detailed Model ◽  
Exterior Surface ◽  
Shell Deformation ◽  
Accuracy Of Measurements ◽  
Correct Representation

Abstract In geodetic measurements of deformations in shell cooling towers, an important factor is to optimize the number of points representing the exterior surface of the shell. The conducted analyses of damage to such structures proved that cooling towers exhibited shell deformation consisting of irregular vertical waves (three concavities and two convexities), as well as seven horizontal waves. On this basis, it is claimed that, in accordance with the Shannon theorem, the correct representation of the generated waves requires the measurement of the cooling tower shell in a minimum of 12 vertical and 14 horizontal sections. Such density of the points may not be sufficient to represent local imperfections of the shell. The article presents the results of test measurements and their analysis, which were conducted to verify the assumptions as to the optimal number of measurement points for the shell of a cooling tower. The evaluation was based on a comparative analysis of the data obtained by the Terrestrial Laser Scanning (TLS) method, creating a very detailed model of geometric imperfections in an actual cooling tower with a height of 100 m. Based on the data obtained by the TLS method, point grids of various density were generated. An additional measurement of the cooling tower shell deformation was performed using a precise electronic total station with reflectorless measurement option. Therefore, it was possible to assess the accuracy of measurements by laser scanning in relation to measurements obtained by reflectorless total stations.

Precise on-line non-target pose measurement for cylindrical components based on laser scanning

2019 ◽  
Vol 39 (4) ◽  
pp. 596-606 ◽  
Author(s):  
Jieyu Zhang ◽  
Yuanying Qiu ◽  
Xuechao Duan ◽  
Changqi Yang
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Synthesis Method ◽  
Side Surface ◽  
3D Vision ◽  
Scanning Method ◽  
Content Type ◽  
New Synthesis ◽  
Surface Damages ◽  
On Line

Purpose Cylindrical components are common in industry assembly areas. It is necessary to obtain their precise positions and orientations for their assemblies. But some measurement approaches relying on measuring targets are not allowed, as they may not meet the efficiency requirement of on-line measurement or may cause surface damages to the components. Thus, this paper aims to provide a precise on-line non-target scanning method based on 3D vision. Design/methodology/approach First, a laser profile sensor is used to acquire point cloud of the side surface of the measured cylindrical component. Then a composite process is conducted to estimate the pose and position of the axis. Aiming at this purpose, two fitting approaches, i.e., axis fitting and generatrix fitting, are tried respectively to estimate the pose parameters from the point cloud. Findings The results of Monte Carlo simulations demonstrate that neither the axis fitting nor the generatrix fitting could solely obtain the needed accuracy and precisions roundly. Thus, a new synthesis method is presented. And the results of prototype experiments validate the excellent accuracy and precision of the synthesis method. Originality/value This proposed new synthesis method combines the advantages of both the above fitting methods and can be easily integrated into the assembly line to guide the automation assembly process of the cylindrical components precisely.

scholarly journals AUTOMATIC INDOOR BUILDING RECONSTRUCTION FROM MOBILE LASER SCANNING DATA

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 417-422 ◽  
Author(s):  
L. Xie ◽  
R. Wang
Keyword(s):  
Laser Scanning ◽  
Recognition Rate ◽  
Synthetic Data ◽  
Main Idea ◽  
Point Clouds ◽  
Outer Wall ◽  
Optimization Method ◽  
Wall Structure ◽  
Point Distribution ◽  
The Individual

Indoor reconstruction from point clouds is a hot topic in photogrammetry, computer vision and computer graphics. Reconstructing indoor scene from point clouds is challenging due to complex room floorplan and line-of-sight occlusions. Most of existing methods deal with stationary terrestrial laser scanning point clouds or RGB-D point clouds. In this paper, we propose an automatic method for reconstructing indoor 3D building models from mobile laser scanning point clouds. The method includes 2D floorplan generation, 3D building modeling, door detection and room segmentation. The main idea behind our approach is to separate wall structure into two different types as the inner wall and the outer wall based on the observation of point distribution. Then we utilize a graph cut based optimization method to solve the labeling problem and generate the 2D floorplan based on the optimization result. Subsequently, we leverage an &amp;alpha;-shape based method to detect the doors on the 2D projected point clouds and utilize the floorplan to segment the individual room. The experiments show that this door detection method can achieve a recognition rate at 97% and the room segmentation method can attain the correct segmentation results. We also evaluate the reconstruction accuracy on the synthetic data, which indicates the accuracy of our method is comparable to the state-of-the art.

scholarly journals 3D Point Cloud Analysis for Damage Detection on Hyperboloid Cooling Tower Shells

2020 ◽  
Vol 12 (10) ◽  
pp. 1542 ◽  
Author(s):  
Maria Makuch ◽  
Pelagia Gawronek
Keyword(s):  
Reinforced Concrete ◽  
Laser Scanning ◽  
Cooling Tower ◽  
Recognition Rate ◽  
Principal Component ◽  
Region Growing ◽  
Inspection System ◽  
Cooling Towers ◽  
Warranty Period ◽  
Automatic Sequence

The safe operation and maintenance of the appropriate strength of hyperboloid cooling towers require special supervision and a maintenance plan that takes into consideration the condition of the structure. With three series of terrestrial laser scanning data, the paper presents an automatic inspection system for reinforced concrete cooling tower shells that ensures detection and measurement of damage together with the verification of the quality and durability of surface repairs as required by industry standards. The proposed solution provides an automatic sequence of algorithm steps with low computational requirements. The novel method is based on the analysis of values of the local surface curvature determined for each point in the cloud using principal component analysis and transformed using the square root function. Data segmentation into cloud points representing a uniform shell and identified defects was carried out using the region growing algorithm. The extent of extracted defects was defined through vectorisation with a convex hull. The proposed diagnostics strategy of reinforced concrete hyperboloid cooling towers was drafted and validated using an object currently under repair but in continuous service for fifty years. The results of detection and measurement of defects and verification of surface continuity at repaired sites were compared with traditional diagnostics results. It was shown that the sequence of algorithm steps successfully identified all cavities, scaling, and blisters in the shell recorded in the expert report (recognition rate—100%). Cartometric vectorisation of defects determined the scope of necessary shell repairs offering higher performance and detail level than direct contact measurement from suspended platforms. Analysis of local geometric features of repaired surfaces provided a reliable baseline for the evaluation of the repairs aimed at restoring the protective properties of the concrete surround, desirable especially in the warranty period.

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