scholarly journals Accuracy Assessment for the Three-Dimensional Coordinates by High-Speed Videogrammetric Measurement

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Xianglei Liu ◽  
Yi Tang ◽  
Jing Ma
Keyword(s):  
High Speed ◽  
Accuracy Assessment ◽  
Three Dimensional ◽  
Shaking Table ◽  
Measuring System ◽  
Accuracy Analysis ◽  
Alternative Technique ◽  
Cmos Camera ◽  
Spatial Coordinates ◽  
Three Dimensional Coordinate

High-speed CMOS camera is a new kind of transducer to make the videogrammetric measurement for monitoring the displacement of high-speed shaking table structure. The purpose of this paper is to validate the three-dimensional coordinate accuracy of the shaking table structure acquired from the presented high-speed videogrammetric measuring system. In the paper, all of the key intermediate links are discussed, including the high-speed CMOS videogrammetric measurement system, the layout of the control network, the elliptical target detection, and the accuracy validation of final 3D spatial results. Through the accuracy analysis, the submillimeter accuracy can be made for the final the three-dimensional spatial coordinates which certify that the proposed high-speed videogrammetric technique is a better alternative technique which can replace the traditional transducer technique for monitoring the dynamic response for the shaking table structure.

scholarly journals TOWARDS MACHINE VISION BASED RAILWAY ASSETS PREDICTIVE MAINTENANCE

2020 ◽  
Vol 19 (2) ◽  
pp. 125
Author(s):  
Ivan Ćirić ◽  
Milan Banić ◽  
Miloš Simonović ◽  
Aleksandar Miltenović ◽  
Dušan Stamenković ◽  
...  
Keyword(s):  
Machine Vision ◽  
High Speed ◽  
Rolling Contact Fatigue ◽  
Three Dimensional ◽  
Contact Fatigue ◽  
Operational Reliability ◽  
Rolling Contact ◽  
Camera System ◽  
Novel Technologies ◽  
Three Dimensional Coordinate

The main goal of this paper is to present novel technologies that can contribute to safety, competitiveness, efficiency and operational reliability of Railway infrastructure through the development of innovative solutions for measuring and monitoring of railway assets based on machine vision. Measuring the transversal position of the wheels on the rail, as well as identification of the defects of the wheel and the rail (such as deformation of rail head edge, lateral wear, worn wheels, cracks in wheel and rail, rolling contact fatigue, corrugation and other irregularities) can increase reliability and lower maintenance costs. Currently, there is a need on the market for the innovative solution, namely the on-board high-speed stereo camera system augmented with a system that projects custom pattern (fringe scanner system) for measuring the transversal position of the wheels on the rail, robust to environmental conditions and waste along the track that can provide reliable measurements of transversal position of the wheels up to 200 km/h. New trends in Precise Industrial 3D Metrology are showing that stereo vision is an absolute must have in modern specialized optical precision measuring systems for the three-dimensional coordinate measurement.

A Dynamic Position Measurement Method for Destructive Process of Structures Using Image Processing

2004 ◽  
Author(s):  
Hiroshi Nishizawa ◽  
Satoshi Fujita ◽  
Osamu Furuya
Keyword(s):  
Image Processing ◽  
High Precision ◽  
High Speed ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Measuring System ◽  
Position Measurement ◽  
Surface Emission ◽  
Optical Motion ◽  
Optical Motion Capture

In order to clarify the destruction mechanism of large structures in large seismic movements, a non-contacting displacement measurement system with a three-dimensional dynamic position with high precision is required. We have developed a three-dimensional measuring system with image processing using optical motion capture technology. This system consists of light emitting markers installed on the object structure and plural high speed cameras which obtain images of markers’ movement simultaneously, to measure the dynamic position of the three dimensional spatial coordinates of the markers. In order to measure the dynamic position with high precision, we have ever developed sub-pixel processing method which is able to measure very small displacements of the markers by analyzing the luminance distribution. Moreover, we have developed a new marker of spherical surface emission type which formed the luminance profile to improve furthermore the accuracy in rotational movement. Shaking tests were carried out with this measuring system and the results indicated that this system using new markers had sufficient accuracy within errors of a few millimeters in the structure of a 4 meter cube. Consequently, we have acquired the potential to apply to the measurement to the 3-D Full Scale Earthquake Testing Facility (E-Defense).

scholarly journals Modelling and optimization of a modified sequential multilateration method for three-dimensional coordinate collection

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988979
Author(s):  
Zhenjiu Zhang ◽  
Mingjun Liu ◽  
Jiaji Jiang ◽  
Linzhong Xia ◽  
Xiaomei Xu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Coordinate Measuring Machine ◽  
Test Point ◽  
Measuring System ◽  
Laser Tracker ◽  
The Monte Carlo Method ◽  
Measuring Machine ◽  
Three Dimensional Coordinate ◽  
The Mathematical Model ◽  
Modelling And Optimization

This article proposes a modified sequential multilateration method for measuring three-dimensional coordinates. The measuring system consists of a single laser tracker and four relay targets whose relative positions have been pre-calibrated by the multilateration method. The laser tracker is fixed on three prescribed positions successively, and these positions can be calibrated by using the distances between the laser tracker and the four relay targets based on the multilateration principle. Subsequently, the three-dimensional coordinates of each under-test point can be determined by the three laser trackers’ positions based on the trilateration principle. This method is more flexible than previous multilateration methods for three-dimensional coordinate collection, especially if the measurement space is partially covered by other objects. The mathematical model of this method is established. Based on the Monte Carlo method, a series of computer simulations are performed to optimize the system arrangement by investigating the performances of the measuring system with different system arrangement, and an optimal system arrangement is finally obtained. Practical measurement is also conducted to demonstrate the validity of the proposed method by comparing with a reference coordinate measuring machine.

scholarly journals Ab initiosimulation of diffractometer instrumental function for high-resolution X-ray diffraction

2015 ◽  
Vol 48 (3) ◽  
pp. 679-689 ◽  
Author(s):  
Alexander Mikhalychev ◽  
Andrei Benediktovitch ◽  
Tatjana Ulyanenkova ◽  
Alex Ulyanenkov
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Calculated Data ◽  
Measured Data ◽  
Universal Method ◽  
Instrumental Function ◽  
Optical Elements ◽  
X Ray ◽  
Detection Point ◽  
Spatial Coordinates

Modeling of the X-ray diffractometer instrumental function for a given optics configuration is important both for planning experiments and for the analysis of measured data. A fast and universal method for instrumental function simulation, suitable for fully automated computer realization and describing both coplanar and noncoplanar measurement geometries for any combination of X-ray optical elements, is proposed. The method can be identified as semi-analytical backward ray tracing and is based on the calculation of a detected signal as an integral of X-ray intensities for all the rays reaching the detector. The high speed of calculation is provided by the expressions for analytical integration over the spatial coordinates that describe the detection point. Consideration of the three-dimensional propagation of rays without restriction to the diffraction plane provides the applicability of the method for noncoplanar geometry and the accuracy for characterization of the signal from a two-dimensional detector. The correctness of the simulation algorithm is checked in the following two ways: by verifying the consistency of the calculated data with the patterns expected for certain simple limiting cases and by comparing measured reciprocal-space maps with the corresponding maps simulated by the proposed method for the same diffractometer configurations. Both kinds of tests demonstrate the agreement of the simulated instrumental function shape with the measured data.

Comparison of Film and Video Techniques for Three-Dimensional DLT Repredictions

1989 ◽  
Vol 5 (4) ◽  
pp. 457-460 ◽  
Author(s):  
Patrick W. Kennedy ◽  
David L. Wright ◽  
Gerald A. Smith
Keyword(s):  
Video Recording ◽  
Three Dimensional ◽  
Transformation Method ◽  
Control Points ◽  
Video Recordings ◽  
Practical Standpoint ◽  
Spatial Coordinates ◽  
Linear Transformation Method ◽  
Three Dimensional Coordinate ◽  
Film And Video

The precision of the kinematic values depends upon the methods of recording a subject’s motion. With the introduction of video recording techniques, questions have arisen concerning the accuracy of video compared with that of 16-mm film. Accordingly, the purpose of this study was to compare the accuracy of the two techniques for point reprediction using the Direct Linear Transformation method. Range poles, serving as boundaries of a cube with 20 known spatial coordinates, were filmed and videotaped. The 20 control points on the film and video recordings were digitized by three individuals. Nine sets of digitized points (three digitizers × three trials) for both film and video were compared with the actual three-dimensional coordinate values. Resultant mean errors were statistically significantly different (p<.05), 4.8 mm and 5.8 mm for film and video, respectively. However, from a practical standpoint the video error was only .29% of the calibrated field compared to .24% for film. Thus it is concluded that video techniques are comparable in accuracy to 16-mm filming methods.

Three-dimensional coordinate measurement algorithm by optimizing BP neural network based on GA

2019 ◽  
Vol 36 (6) ◽  
pp. 2066-2083 ◽  
Author(s):  
Xiaohong Lu ◽  
Yongquan Wang ◽  
Jie Li ◽  
Yang Zhou ◽  
Zongjin Ren ◽  
...  
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Back Propagation ◽  
Three Dimensional ◽  
Measuring System ◽  
Content Type ◽  
Coordinate Measurement ◽  
World Coordinate System ◽  
Measurement Algorithm ◽  
Three Dimensional Coordinate

Purpose The purpose of this paper is to solve the problem that the analytic solution model of spatial three-dimensional coordinate measuring system based on dual-position sensitive detector (PSD) is complex and its precision is not high. Design/methodology/approach A new three-dimensional coordinate measurement algorithm by optimizing back propagation (BP) neural network based on genetic algorithm (GA) is proposed. The mapping relation between three-dimensional coordinates of space points in the world coordinate system and light spot coordinates formed on dual-PSD has been built and applied to the prediction of three-dimensional coordinates of space points. Findings The average measurement error of three-dimensional coordinates of space points at three-dimensional coordinate measuring system based on dual-PSD based on GA-BP neural network is relatively small. This method does not require considering the lens distortion and the non-linearity of PSD. It has simple structure and high precision and is suitable for three-dimensional coordinate measurement of space points. Originality/value A new three-dimensional coordinate measurement algorithm by optimizing BP neural network based on GA is proposed to predict three-dimensional coordinates of space points formed on three-dimensional coordinate measuring system based on dual-PSD.

Circular Dynamic Stereoscopy and Its Application for Fluid Measurement

2004 ◽  
Vol 126 (1) ◽  
pp. 42-47
Author(s):  
Kikuhito Kawasue ◽  
Yuichiro Oya ◽  
Takakazu Ishimatsu
Keyword(s):  
High Speed ◽  
Tracer Particle ◽  
Three Dimensional ◽  
Image Plane ◽  
Positional Information ◽  
Video Camera ◽  
Measuring System ◽  
Original Position ◽  
Video Capture ◽  
Typical Application

By attaching a refractor to the lens of a Video Capture Device (e.g., CCD Video Camera) it is possible to record optical displacements from the original position of any object (tracer particle) within the image plane. If the refractor is physically rotated around the optical axis at high speed, the tracer particles create annular streaks due to the effect caused by the refractor’s circular shift. The perceived displacements are added to the image being recorded by the Video Capture Device (VCD). Additionally, these displacements are directly related to the distance between the VCD and the particle being measured: the magnitude of displacement on the image plane being inversely proportional to the distance between the VCD and point of measurement. Since the radius of each annular streak, of a point being measured, is inversely proportional to its distance from the VCD, it is therefore possible by analyzing these annular streaks, to determine the three dimensional positional information of the point. Thus the radius of the annular streaks on the image plane determines the z coordinate, while the geometric center provides the x and y coordinates. The theory and setup of such a measuring system is subsequently presented, and the measurement of a moving surface, such as moving water, is used to demonstrate a typical application of such a system.

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