Automatic measuring method of catenary geometric parameters based on laser scanning and imaging

2018 ◽  
Author(s):  
Songhong Chang ◽  
Luhua Fu ◽  
Changjie Liu
Keyword(s):  
Laser Scanning ◽  
Measuring Method ◽  
Geometric Parameters ◽  
Automatic Measuring ◽  
Automatic Measuring Method

An automatic measuring method and system using laser triangulation scanning for the parameters of a screw thread

2014 ◽  
Vol 25 (3) ◽  
pp. 035202 ◽  
Author(s):  
Qing-bin Tong ◽  
Chao-qun Jiao ◽  
Hui Huang ◽  
Gui-bin Li ◽  
Zhen-liang Ding ◽  
...  
Keyword(s):  
Measuring Method ◽  
Laser Triangulation ◽  
Screw Thread ◽  
Automatic Measuring ◽  
Automatic Measuring Method

The Application of 3D Laser Scanning Method in the Measurement of Pressure Vessel

2017 ◽  
Vol 865 ◽  
pp. 595-598
Author(s):  
Hui Zeng Yin ◽  
Xin Wei Yang ◽  
Rui Lan Tian ◽  
Xiu Zhi Sui
Keyword(s):  
Pressure Vessel ◽  
Point Cloud ◽  
Laser Scanning ◽  
Convex Surface ◽  
Measuring Method ◽  
Point Cloud Data ◽  
3D Laser Scanning ◽  
Scanning Method ◽  
Cloud Data ◽  
Dangerous Goods

Pressure vessel is widely used in the industrial engineering. Many materials in pressure vessel are inflammable and explosive dangerous goods. If the accident happens, great harm will be done to the lives and properties of people. Some common methods for studying pressure vessel have obvious drawbacks. 3D laser scanning method uses non-contact measuring method and can directly obtain the point cloud data of the mass surface which can be used to reconstruct any convex surface. According to the advantages of 3D laser scanning method, in this paper, it is introduced to measure the dimensions of flanges in pressure vessel. The experimental results obtained have little errors, which certify that 3D laser scanning method can be used to measure the dimensions of flanges and further study the characteristics of pressure vessel.

Measuring Method of Material Constants Using a Laser Scanning Micrometer at High Temperature

2000 ◽  
Vol 2000 (0) ◽  
pp. 291-292
Author(s):  
Kana KAMITSUBO ◽  
Hiroaki ISONO ◽  
Katsuhiko YASUDA ◽  
Koichiro KIHARA ◽  
Toshio SUGIBAYASHI
Keyword(s):  
High Temperature ◽  
Laser Scanning ◽  
Measuring Method ◽  
Material Constants

scholarly journals ALGORITHM FOR THE AUTOMATIC ESTIMATION OF AGRICULTURAL TREE GEOMETRIC PARAMETERS USING AIRBORNE LASER SCANNING DATA

2016 ◽  
Vol XLI-B8 ◽  
pp. 629-632 ◽  
Author(s):  
E. Hadaś ◽  
A. Borkowski ◽  
J. Estornell
Keyword(s):  
Laser Scanning ◽  
Tree Height ◽  
Field Measurements ◽  
Point Clouds ◽  
Average Density ◽  
Geometric Parameters ◽  
Airborne Laser Scanning ◽  
Maximum Height ◽  
Airborne Laser ◽  
Crown Base Height

The estimation of dendrometric parameters has become an important issue for the agricultural planning and management. Since the classical field measurements are time consuming and inefficient, Airborne Laser Scanning (ALS) data can be used for this purpose. Point clouds acquired for orchard areas allow to determine orchard structures and geometric parameters of individual trees. In this research we propose an automatic method that allows to determine geometric parameters of individual olive trees using ALS data. The method is based on the α-shape algorithm applied for normalized point clouds. The algorithm returns polygons representing crown shapes. For points located inside each polygon, we select the maximum height and the minimum height and then we estimate the tree height and the crown base height. We use the first two components of the Principal Component Analysis (PCA) as the estimators for crown diameters. The α-shape algorithm requires to define the radius parameter <i>R</i>. In this study we investigated how sensitive are the results to the radius size, by comparing the results obtained with various settings of the R with reference values of estimated parameters from field measurements. Our study area was the olive orchard located in the Castellon Province, Spain. We used a set of ALS data with an average density of 4 points&thinsp;m<sip>&minus;2</sup>. We noticed, that there was a narrow range of the <i>R</i> parameter, from 0.48&thinsp;m to 0.80&thinsp;m, for which all trees were detected and for which we obtained a high correlation coefficient (>&thinsp;0.9) between estimated and measured values. We compared our estimates with field measurements. The RMSE of differences was 0.8&thinsp;m for the tree height, 0.5&thinsp;m for the crown base height, 0.6&thinsp;m and 0.4&thinsp;m for the longest and shorter crown diameter, respectively. The accuracy obtained with the method is thus sufficient for agricultural applications.

An Approach for the Scanning and Construction of Biofouled Surfaces to be used for Drag Measurements

2017 ◽  
Author(s):  
Christina Dehn ◽  
Eric Holm ◽  
Peter Chang ◽  
Abel Vargas ◽  
Scott Storms
Keyword(s):  
Channel Flow ◽  
Laser Scanning ◽  
Surface Characterization ◽  
Rough Surfaces ◽  
Surface Preparation ◽  
Turbulent Channel Flow ◽  
Geometric Parameters ◽  
Navier Stokes ◽  
Ship Hulls ◽  
Cfd Method

A methodology for digitizing and processing calcareous biofouling typically found on US Navy ship hulls has been developed. Panels that were immersed in seawater and allowed to grow biofouling were captured using 3-D laser scanning. The advantage of these digital replicas over real biofouled rough surfaces are many-fold: the surfaces can be manipulated to meet channel flow and large eddy simulation (LES) viscous size constraints; 3-D printing can then be used to build scaled rough surfaces that can be used in the fully developed turbulent channel flow; complex statistical and geometric parameters that encapsulate drag-producing physics can be computed; subregions of the surfaces can be tiled together to create composite surfaces that can span various parameter spaces. This paper describes, in detail, the digitizing, surface preparation, and 3-D printing methodologies. In addition, it describes the surface characterization software. Data from nine scanned surfaces, with biofouling from coastal Florida and Pearl Harbor, Hawaii are shown with preliminary correlations between pierside data and more complex geometric parameters. The work described herein is part of a larger project to develop a fast and accurate ReynoldsAveraged Navier Stokes (RANS) computational fluid dynamics (CFD) method to predict the drag penalty of fouled ships based on data obtained from pierside underwater surveys.

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