• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.208-219
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• 2002

A novel measurement method to obtain the 6-DOF motions of arbitrary rigid bodies is proposed in this paper. The method adopts a specially fabricated mirror called 3-facet mirror, which looks like a triangular pyramid haying an equilateral cross-sectional shape. The mirror is mounted on the objects to be measured, illuminated by a laser beam having circular profile, and reflects the laser beam in three different directions. Three PSDs(position sensitive detector) detect the three beams reflected by the mirror, respectively. From the signals of the PSDs, we can calculate the 3-dimensional position and orientation of the 3-facet mirror, and thus enabling us to determine the 3-dimensional position and orientation of the objects. In this paper, we model the relationship between the 3-dimensional position and orientation of an object in motion and the outputs of three PSDs. A series of experiments are performed to demonstrate the effectiveness and accuracy of the proposed method. The experimental results show that the proposed sensing system can be an effective means of obtaining 3-dimensional position and orientation of arbitrary objects and provide resonable measurement accuracy.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.2
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• pp.37-42
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• 2016

This paper proposes a method to develop a high-precision dimension measurement system using a linear variable differential transformer sensor. The Dimension targets for measurement is carbon material vanes of key element in the rotating parts within vehicle circulating pump. Data acquisition system for dimension measurement is designed using the NI Compact RIO. And the program applying the dimension measurement algorithm is built using NI LabVIEW. The dimension measuring program is composed of a FPGA program, Real Time program and Host program. The method of the experiment compares master vane with target vane for measure the length of the carbon material vane. The experimental results confirmed the usefulness of the accuracy within ${\pm}4um$.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.2
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• pp.55-61
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• 2005

The machining Parts must be Produced within the specification of drawing and those will be able to meet faction and efficiency. At that time, it is very important not only precision machine and machining technique but also the measurement technique. So, the improvement of measurement technique is to be joined together at once with improvement of machining technique. Finally, the quality and value of the parts are decided by precision measurement. This paper aims to study on the measurement uncertainty when the machined parts are inspected with 3-dimensional coordinate measuring machine. The objectives remove an error of measurement and remove a quality of mass products.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1409-1417
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• 2003

In the 21st century, the concept of remote design and manufacture is strongly required in manufacturing processes to reduce cost and time-to-market. The objective of this paper is the development of an internet-based dimensional verification system for reverse engineering. An inspection client can register measurement data at the developed web server. Collaborators related to the development of a new product can confirm geometrical form from measurement data, check dimensional information and mark up the important parts, as well as make a statement of their views through the Internet. The developed system is realized through the ActiveX-Server architecture. Functions of the dimensional verification module are constructed as ActiveX by using the visual C＋＋ and OpenGL. The usefulness of the developed system is confirmed through a case study.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.4
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• pp.190-196
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• 2001

We measured 3-dimensional images of the light emitted from plasma display panel(PDP) by using newly proposed scanned point detecting method(SPDM). The SPDM has the point detector with pinhole. The light emitted from PDP cell at the in-focus position can pass through the pinhole and be collected by detector. On the contrary, the light emitted from PDP cell at the out-of-focus positions is focused on the front of or the behind of the pinhole. We could analyze the characteristic of 3-dimensional light emission distribution by SPDM. From 3-dimensional measurement of 828[nm], the efficient design of PDP cell, the importance of opening ration, and the relations between BUS electrode position and discharge intensity are obtained. Also, the relationship between discharge characteristics and sustain electrode structures in AC-PDP are studied by measuring luminance, current, and discharge voltage.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1011-1016
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• 2015

Gas piping systems in power plants and factories are always influenced by the mechanical vibrations of rotational machines such as pumps, blowers, and compressors. Unusual vibrations in a gas piping system influence possible leakages of liquids or gases, which can lead to large explosive accidents. Real-time measurements of unusual vibrations in piping systems in situ prohibit them from being possible leakages owing to the repeated fatigue of vibrations. In this paper, a non-contact 3-dimensional measurement system that can detect the vibrations of a solid body and monitor its vibrational modes is introduced. To detect the displacements of a body, a stereoscopic camera system is used, through which the major vibration types of solid bodies (such as X-axis-major, Y-axis-major, and Z-axis-major vibrations) can be monitored. In order to judge the vibration types, an artificial neural network is used. The measurement system consists of a host computer, stereoscopic camera system (two-camera system, high-speed high-resolution camera), and a measurement target. Through practical application on a flat plate, the measured data from the non-contact measurement system showed good agreement with those from the original vibration mode produced by an accelerator.

• Clinics in Shoulder and Elbow
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• v.23 no.3
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• pp.119-124
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• 2020

Background: This study was performed to compare glenoid version and inclination measured using two-dimensional (2D) images from computed tomography (CT) scans or three-dimensional (3D) reconstructed bone models. Methods: Thirty patients who had undergone conventional CT scans were included. Two orthopedic surgeons measured glenoid version and inclination three times on 2D images from CT scans (2D measurement), and two other orthopedic surgeons performed the same measurements using 3D reconstructed bone models (3D measurement). The 3D-reconstructed bone models were acquired and measured with Mimics and 3-Matics (Materialise). Results: Mean glenoid version and inclination in 2D measurements were -1.705° and 9.08°, respectively, while those in 3D measurements were 2.635° and 7.23°. The intra-observer reliability in 2D measurements was 0.605 and 0.698, respectively, while that in 3D measurements was 0.883 and 0.892. The inter-observer reliability in 2D measurements was 0.456 and 0.374, respectively, while that in 3D measurements was 0.853 and 0.845. Conclusions: The difference between 2D and 3D measurements is not due to differences in image data but to the use of different tools. However, more consistent results were obtained in 3D measurement. Therefore, 3D measurement can be a good alternative for measuring glenoid version and inclination.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.115-122
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• 2005

Errors resulting from magnification variations of a optical system are largely generated in three-dimensional shape measurements based on depth-from-focus. In the case of measuring the surface morphology of tiny objects based on DFF, images are acquired with a very small interval so that magnification changes can be minimized. However, the magnification variations are actually existed in the acquired images and so focus measures are wrongly or ambiguously extracted. In this paper, a methodology with linear magnification calibrations, based on DFF, is proposed to make more accurate measurement in surface morphology with high depth discontinuity, compared with previous ones. Several experiments show that the proposed method outperforms existing ones without magnification calibrations.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.407-415
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• 1993

This report presents an automatic measurement method of 3-dimensional profiles of free-formed surfaces, by using a touch a touch-trigger contact probe along with a conventional coordinate measuring machine. The method proceeds in three steps; The surface profile under consideration is traced by the probe in an automatic manner, and then its measured data is compensated by considering the actual probe radius. Finally the compensated data is rearranged in the form suitable for the further processings of CAD/CAM applications. Some experimental results are discussed to verify the validity of the method suggested in this study.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.159-165
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• 1999

Based on the cable-extension transducers, a new technique for two dimensional position measurement is developed in this paper. This new technique includes the use of two such transducers and the planar position is determined through triangulation. This paper also presents uncertainty analysis results for establishing sensor design specifications. An actual prototyped sensor system is built and its accuracy is verified through h\both experiments with coordinate measurement machines and its application to the real-time control of a high load wheeled mobile robot. This new type of position sensor can be easily used in a wide variety of automation applications in industry for two dimensional position measurements with high accuracy over a relatively large range, and it is both cast effective and robust against hostile environments.