scholarly journals Automatic 3D Measurement System by the Grid Illumination Type Moire Method

1991 ◽  
Vol 3 (3) ◽  
pp. 177-183
Author(s):  
Yasuhiko Arai ◽  
◽  
Shunsuke Yokozeki ◽  
Tomoharu Yamada ◽  
Keyword(s):  
Liquid Crystal ◽  
Three Dimensional ◽  
Measuring System ◽  
Measuring Instruments ◽  
3D Measurement ◽  
Fringe Order ◽  
Scanning Method ◽  
Moire Method ◽  
3D Measurement System ◽  
Moiré Topography

This paper describes an installation of the fringe scanning method into a shadow-type Moire Topography. The result is a high-precision three-dimensional measuring system and automatic fringe order measuring system using a liquid crystal plate. A description of this fullyautomatic measuring system, which does not require the user to have knowledge of measuring instruments, is also provided. This system was constructed by achieving the automation of Moire topography, which is regarded as difficult due to problems concerning the linkage of independent processes. The validity of the system is illustrated by experimental results for spheres and for planes with a difference in level.

Calibration Algorithm for Error Screening Based on Line Structured Light

2020 ◽  
Vol 29 (07n08) ◽  
pp. 2040013
Author(s):  
Baolong Liu ◽  
Ruixia Wu ◽  
Yu Liu
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
Small Error ◽  
Calibration Error ◽  
3D Measurement ◽  
Screening Model ◽  
Calibration Algorithm ◽  
On Line ◽  
3D Measurement System ◽  
Compensation Function

The 3D measurement system based on line-structured light uses a camera to capture laser stripes due to changing in the shape of an object, and uses the acquired pixel coordinates for 3D reconstruction. System calibration is an important step in 3D measurement. The current camera calibration algorithm research mainly focuses on improving the algorithm itself, and there is less research on the influence of external factors. This paper proposes a coplanar hybrid calibration algorithm based on the error screening model by combining the error screening model, mathematical model and neural network model. It is mainly divided into two steps. The first step is to use the radial array constraint calibration algorithm based on the error screening model to solve the camera’s internal and external parameters. The second step uses the camera internal and external parameters obtained in the first step to convert the pixel coordinates into real three-dimensional coordinates, and compares the calculated three-dimensional coordinates with the actual coordinates. Using machine learning to establish a compensation network, get a compensation function, and use the resulting 3D world coordinates to perform point cloud stitching. Experiments show that compared with the traditional calibration algorithm, the calibration algorithm has a small error and reduces the calibration error by about 6.5%.

A Structured-Light-Based On-Line 3D Measurement System and Software Development

2005 ◽  
Vol 295-296 ◽  
pp. 399-404
Author(s):  
X.Y. Yu ◽  
F.B. Zhang ◽  
H.J. Yuan ◽  
Z.G. Lang
Keyword(s):  
Measurement System ◽  
High Speed ◽  
Structured Light ◽  
Measuring System ◽  
Depth Image ◽  
Measuring Error ◽  
3D Measurement ◽  
Vision Measurement ◽  
On Line ◽  
3D Measurement System

The objective of this work is to develop a 3D measuring system for on-line 3D measurement in industry locale. Our system is based on the depth image using a structured-light method. A generator emitting a single stripe light and a camera are used to establish a 3D vision measurement system which is also called as a subsystem. But it only can obtain the depth image of a part at the measured object section. Our system is made up of four subsystems placed symmetrically in space. The depth images obtained by the subsystems are joined to form the depth image of a full section. If the object is uniformly shafted along a fixed beeline direction, the depth image of the full object surface is achieved. The indefiniteness in the image combination criterion can be removed when using the depth image. This paper introduces the system principle and the mathematical model. The algorithm is proposed with system parameters. A prototype is developed. The system has the range of 100mm in height x 100mm in width. The length is not limited. The measuring error is less than 0.5mm in height and width and less than 0.01mm in length. The characteristics make the system suitable for on-line 3D shape measurement and non-contact measurement with high speed.

Rapid Prototyping of Handicraft Based on Reverse Engineering

2011 ◽  
Vol 109 ◽  
pp. 451-454 ◽  
Author(s):  
Xiao Min Cheng ◽  
Zi Qing Ye ◽  
Xin Hua Yi
Keyword(s):  
Rapid Prototyping ◽  
Reverse Engineering ◽  
Three Dimensional ◽  
Rapid Prototype ◽  
Point Clouds ◽  
Data File ◽  
3D Measurement ◽  
Collection Data ◽  
3D Measurement System ◽  
Dimensional Picture

Reverse Engineering of handicrafts refers to many aspects, such as data collection, data mergence of point clouds, surfaces reconstruction, and rapid prototyping. This paper takes a handicraft horse for example. Once this horse is scanned partially by using non-contact optical 3D measurement system, we can get point clouds data, and accumulate, merge, and combine them into one data file, then build up a three-dimensional picture, and obtain STL format file after slicing. Finally, rapid prototype manufacture can be used. By using this method, handicrafts that are the same as or similar with the mock-ups can be produced.

Hand-Held Blue Light 3D Measurement Technology and its Application in Hot Stamping

2014 ◽  
Vol 1063 ◽  
pp. 362-366 ◽  
Author(s):  
Guo Min Zhan ◽  
Zhong Wei Li ◽  
Xing Jian Liu ◽  
Kai Zhong
Keyword(s):  
Blue Light ◽  
Measurement Accuracy ◽  
Hot Stamping ◽  
Three Dimensional ◽  
High Strength ◽  
Measurement Technology ◽  
3D Measurement ◽  
Single Measurement ◽  
Reflectance Measurement ◽  
3D Measurement System

Over the last few years hot stamping for its high strength, lightweight characteristics has developed at an alarming rate, At the same time the measurement process a higher demand. Compared with the traditional three-dimensional coordinate measurement, Hand-held Blue structured Light 3D measurement technology for its fast, high precision, good flexibility, etc., has become the best choice of high-strength steel stamping in non-contact 3D measurement and accuracy detection. This paper developed a set of holding blue light 3D measurement system. The system project blue structured pattern to the surface of the object, and captured by two high-speed cameras synchronized. Then using the grabbed pictures reconstruct 3D topography of the object. Blue light projection technology can eliminate the use of influence of different surface reflectance measurement accuracy, So that a single measurement accuracy of 0.02mm, overall measurement accuracy of 0.05mm / m, Single measurement time is less than 0.12 seconds. This measuring system can be widely used in the rapid detection of various types of three-dimensional measurement and precision casting.

Measurement of erosion state and refractory lining thickness of blast furnace hearth by using three-dimensional laser scanning method

2020 ◽  
Vol 118 (1) ◽  
pp. 106
Author(s):  
Lei Zhang ◽  
Jianliang Zhang ◽  
Kexin Jiao ◽  
Guoli Jia ◽  
Jian Gong ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Laser Scanning ◽  
Refractory Lining ◽  
Three Dimensional ◽  
3D Laser Scanning ◽  
Scanning Method ◽  
Blast Furnace Production ◽  
Severe Erosion ◽  
Residual Thickness ◽  
Minimum Depth

The three-dimensional (3D) model of erosion state of blast furnace (BF) hearth was obtained by using 3D laser scanning method. The thickness of refractory lining can be measured anywhere and the erosion curves were extracted both in the circumferential and height directions to analyze the erosion characteristics. The results show that the most eroded positions located below 20# tuyere with an elevation of 7700 mm and below 24#–25# tuyere with an elevation of 8100 mm, the residual thickness here is only 295 mm. In the circumferential directions, the serious eroded areas located between every two tapholes while the taphole areas were protected well by the bonding material. In the height directions, the severe erosion areas located between the elevation of 7600 mm to 8200 mm. According to the calculation, the minimum depth to ensure the deadman floats in the hearth is 2581 mm, corresponding to the elevation of 7619 mm. It can be considered that during the blast furnace production process, the deadman has been sinking to the bottom of BF hearth and the erosion areas gradually formed at the root of deadman.

Development of a Visual Monitoring System for Deformation Measuring of Welded Members and its Application

2008 ◽  
Vol 580-582 ◽  
pp. 557-560 ◽  
Author(s):  
J.G. Han ◽  
Kyong Ho Chang ◽  
Gab Chul Jang ◽  
K.K. Hong ◽  
Sam Deok Cho ◽  
...  
Keyword(s):  
Monitoring System ◽  
Three Dimensional ◽  
Measuring Method ◽  
Welding Residual Stress ◽  
Measuring System ◽  
Visual Monitoring ◽  
Test Error ◽  
Steel Members ◽  
Loading Tests ◽  
Visual Monitoring System

Recently, in the loading tests for steel members, the deformation value is measured by calculating a distance of both cross-heads. This measuring method encounters a test error due to various environmental factors, such as initial slip, etc.. Especially, in the case of welded members, the non-uniform deformation behavior in welded joints is observed because of the effect of welding residual stress and weld metal. This is mainly responsible for a test error and a loss of the reliability for used test instruments. Therefore, to improve the accuracy and the applicability of measuring system, it is necessary to employ a visual monitoring system which can accurately measure the local and overall deformation of welded members. In this paper, to accurately measure a deformation of welded members, a visual monitoring system (VMS) was developed by using three-dimensional digital photogrammetry. The VMS was applied to the loading tests of a welded member. The accuracy and the applicability of VMS was verified by comparing to the deformation value measured by a test instrument (MTS-810). The characteristics of the behavior near a welded joint were investigated by using VMS.

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