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.

Precision Comparison of 3D Measurement System Based on Stereo Vision

2012 ◽  
Vol 542-543 ◽  
pp. 635-638
Author(s):  
Ke Zhang ◽  
Zhao Gao
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Quality Control ◽  
Stereo Vision ◽  
Measurement System ◽  
Bp Neural Network ◽  
Robot Vision ◽  
Measurement Technology ◽  
3D Measurement ◽  
3D Measurement System

The 3D measurement based on stereo vision, as a new measurement technology, has been widely used in reverse engineering, robot vision and quality control, etc. In this paper, the basic principle and method of calibrating 3D measurement system based on stereo vision respectively using genetic algorithm and neural network was introduced. Then the measurement system was calibrated and the precision of 3D measurement system was compared. The experimental results indicate that the method based on BP neural network can improve the precision of measurement better.

scholarly journals Studies on Three-Dimensional (3D) Accuracy Optimization and Repeatability of UAV in Complex Pit-Rim Landforms As Assisted by Oblique Imaging and RTK Positioning

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8109
Author(s):  
Rui Bi ◽  
Shu Gan ◽  
Xiping Yuan ◽  
Raobo Li ◽  
Sha Gao ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Three Dimensional ◽  
Surface Model ◽  
Observation Data ◽  
3D Measurement ◽  
Oblique View ◽  
Mountain Environments ◽  
Repeated Observation ◽  
Order Of Magnitude ◽  
Oblique Images

Unmanned Aerial Vehicles (UAVs) are a novel technology for landform investigations, monitoring, as well as evolution analyses of long−term repeated observation. However, impacted by the sophisticated topographic environment, fluctuating terrain and incomplete field observations, significant differences have been found between 3D measurement accuracy and the Digital Surface Model (DSM). In this study, the DJI Phantom 4 RTK UAV was adopted to capture images of complex pit-rim landforms with significant elevation undulations. A repeated observation data acquisition scheme was proposed for a small amount of oblique-view imaging, while an ortho-view observation was conducted. Subsequently, the 3D scenes and DSMs were formed by employing Structure from Motion (SfM) and Multi-View Stereo (MVS) algorithms. Moreover, a comparison and 3D measurement accuracy analysis were conducted based on the internal and external precision by exploiting checkpoint and DSM of Difference (DoD) error analysis methods. As indicated by the results, the 3D scene plane for two imaging types could reach an accuracy of centimeters, whereas the elevation accuracy of the orthophoto dataset alone could only reach the decimeters (0.3049 m). However, only 6.30% of the total image number of oblique images was required to improve the elevation accuracy by one order of magnitude (0.0942 m). (2) An insignificant variation in internal accuracy was reported in oblique imaging-assisted datasets. In particular, SfM-MVS technology exhibited high reproducibility for repeated observations. By changing the number and position of oblique images, the external precision was able to increase effectively, the elevation error distribution was improved to become more concentrated and stable. Accordingly, a repeated observation method only including a few oblique images has been proposed and demonstrated in this study, which could optimize the elevation and improve the accuracy. The research results could provide practical and effective technology reference strategies for geomorphological surveys and repeated observation analyses in sophisticated mountain environments.

Measurement of Three-Dimensional Environment with a Fish-Eye Camera Based on Structure from Motion - Error Analysis

2009 ◽  
Vol 21 (6) ◽  
pp. 680-688 ◽  
Author(s):  
Kenji Terabayashi ◽  
◽  
Hisanori Mitsumoto ◽  
Toru Morita ◽  
Yohei Aragaki ◽  
...  
Keyword(s):  
Structure From Motion ◽  
Measurement Accuracy ◽  
Three Dimensional ◽  
Simultaneous Estimation ◽  
3D Measurement ◽  
Motion Error ◽  
3 Dimensional ◽  
Wide Range ◽  
Large Distortion ◽  
Fish Eye

This paper proposes a method for measuring 3-dimensional (3D) environment and estimating camera movement with two fish-eye images. This method deals with large distortion of images from a fish-eye camera to calibrate internal and external camera parameters precisely by simultaneous estimation. In this paper, we analyze 3D measurement accuracy based on a theoretical model and evaluate it in practical analysis in experimental and real environments. These analyses show that the theoretical measurement error model works over a wide range of fish-eye views.

scholarly journals 3D Measurement of Discontinuous Objects with Optimized Dual-frequency Grating Profilometry

2021 ◽  
Vol 21 (6) ◽  
pp. 197-204
Author(s):  
Jun Che ◽  
Yanxia Sun ◽  
Xiaojun Jin ◽  
Yong Chen
Keyword(s):  
Light Intensity ◽  
Measurement Accuracy ◽  
High Reliability ◽  
Three Dimensional ◽  
Fringe Projection ◽  
Intensity Difference ◽  
3D Measurement ◽  
Dual Frequency ◽  
Processing Scheme ◽  
Blind Spots

Abstract Three-dimensional profilometry tends to be less effective at measuring discontinuous surfaces. To overcome this problem, an optimized profilometry based on fringe projection is proposed in this paper. Due to the limitation of the shooting angle, there are projection blind spots on the surface of discontinuous objects. Since the noises and unwrapping errors are always localized at the projection blind spots, an algorithm is designed to determine the blind spots automatically with the light intensity difference information. Besides, in order to improve the measurement accuracy, a processing scheme is introduced to deal with the local height distortion introduced by the dual-frequency grating profilometry. Lots of measurement tests on various surfaces are carried out to assess the optimized profilometry, and experimental results indicate that the modified profilometry system works more robust with high reliability and accuracy in measuring different kinds of surfaces, especially discontinuous ones.

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%.

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.

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.

A novel predictive method for filler coflocculation with cellulose microfibrils

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 653-664
Author(s):  
IGNACIO DE SAN PIO ◽  
KLAS G. JOHANSSON ◽  
PAUL KROCHAK
Keyword(s):  
Negative Impact ◽  
High Strength ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Paper Strength ◽  
Flow Loop ◽  
Cationic Starch ◽  
Reflectance Measurement ◽  
Drainage Rate ◽  
Complete Study

Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.

scholarly journals Compressive behaviours of octet-truss lattices

2020 ◽  
Vol 234 (16) ◽  
pp. 3257-3269 ◽  
Author(s):  
Yifan Li ◽  
Huaiyuan Gu ◽  
Martyn Pavier ◽  
Harry Coules
Keyword(s):  
Failure Modes ◽  
Density Ratio ◽  
Three Dimensional ◽  
Compressive Load ◽  
High Strength ◽  
Detailed Comparison ◽  
Compressive Response ◽  
Beam Elements ◽  
Structural Applications ◽  
Octet Truss

Octet-truss lattice structures can be used for lightweight structural applications due to their high strength-to-density ratio. In this research, octet-truss lattice specimens were fabricated by stereolithography additive manufacturing with a photopolymer resin. The mechanical properties of this structure have been examined in three orthogonal orientations under the compressive load. Detailed comparison and description were carried out on deformation mechanisms and failure modes in different lattice orientations. Finite element models using both beam elements and three-dimensional solid elements were used to simulate the compressive response of this structure. Both the load reaction and collapse modes obtained in simulations were compared with test results. Our results indicate that three-dimensional continuum element models are required to accurately capture the behaviour of real trusses, taking into account the effects of finite-sized beams and joints.

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