• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.483-486
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• 2004

A CCD-based color uniformity measurement system was set up. Through measuring the two-dimensional brightness distributions of three primary colors on the screen, chromaticity coordinate distributions of combination gray can be obtained within a few seconds. This system can be widely used in the production of LCD projection.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.41-48
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• 2019

This paper deals with a method of aligning an aircraft fuselage and an inertial navigation sensor using three-dimensional coordinates obtained by an optical method. In order to verify the feasibility, we introduce the method to accurately align the coordinate system of the inertial navigation sensor and the aircraft reference coordinate system. It is verified through simulation that reflects the error level of the measuring device. In addition, optimization method based alignment algorithm is proposed for connection between optical sensor and inertial navigation sensor.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.427-433
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• 2010

With recent increased demand for reverse engineering in dental machining, the 3D laser scanner is widely used for inspection of artificial pontic. In order to overcome the optical drawback of laser scanner, such as irregular scatter, direction of beam, and the influence of surface integrity, it is developed in this study a new 3D measuring system for artificial pontic using spherical coordinate system mechanism by point laser sensor, which keeps the direction of beam normal to surface consistently. The comprehensive integrated system is established to evaluate the improvement of accuracy with data acquisition system. The experimental results for measuring a master ball and pontic models shows the excellent form accuracy and repeatability compared with conventional apparatus. Also, these results shows the possibility to apply this system for the measuring purpose within 0.05mm accuracy of pontic at the sharp edge or margin contour, which was difficult to measure at the conventional systems.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.6
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• pp.111-116
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• 2018

Recently, shape manufacturing method has been changed to a 3D printer. Since lamination type manufacturing method is the basis for forming a three-dimensional shape by repeated lamination, the horizontal accuracy of the lamination layer is very important. In the current paper, we have proposed a new leveling system to be installed in a large 3D printer. The light source was reflected from the water surface contained in the measuring device, and the inclination of the measuring device was measured from the light that entered into four regions of a quarter photodetector. The electrical signals generated differently according to the position of the beam spot incident on the quarter photodetector was acquired and compensated to be horizontal by using a motor mounted at the corner. Compared to a digital leveler, the newly developed leveling system gave errors of only 2 to 3%. This new device can be applied to various fields including the 3D printer in future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1959-1965
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• 2011

Measuring the movement of joint angle of human body is very important clinically. Human joint angle displacement can be used to evaluate the degree of disease and disability. Also, we can determine the rehabilitation process with angular information. Conventional methods for measuring angular displacement are many weakness. The purpose of this study is to overcome the limitations of existing equipments by using optical method. For this reason, optical sensor system was used to correlate detected light signal with joint angle. Experimental results of the applied joint model in this study showed that joint angular displacement can be measured by optical signals. The suggested method is simple, durable, small, lightweight, convenient, and cost effective.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1241-1246
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• 2007

In recent years, the semiconductor industry and the optical industry are developed rapidly. The recent demands have expanded for optical components such as the optical lens, the optical semiconductor and the measuring instrument. Object transport systems are driven typically by the magnetic field and the conveyer belt. Recent industry requires more faster and efficient transport system. However, conventional transport systems are not adequate for transportation of optical elements and semiconductors. The conveyor belts can damage precision optical elements by the contact force and magnetic systems can destroy the inner structure of semiconductor by the magnetic field. In this paper, the levitation transport system using ultrasonic wave is developed for transporting precision elements without damages. The steady state flexural vibration of the beam is expressed using Euler-Bernoulli beam theory. The transport direction of an object is examined according to phase difference and frequency. The theoretical results are verified by experiments.

• Publications of The Korean Astronomical Society
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• v.19 no.1
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• pp.71-76
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• 2004

We have developed a tool for measuring optical aberrations of telescope. We adopt curvature sensing technique and use the least square method for finding the amplitudes of the Zernike polynomials. This tool runs under the PC Linux system and the PC windows system with Linux emulators such as Cygwin. The program for UNIX system is used for optical alignment of 1.8M optical telescope at the Bohyunsan Optical Astronomical Observatory (BOAO) and the PC based program is used for the Korea Astronomy Observatory (KAO) wide field telescope (named NEOPAT-3). Our tool is found to be efficient for precise measurement of the optical aberrations of telescopes.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.219-222
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• 2002

In this paper, some parameters are studied for the performance improvement of a bulk optical magnetic-field sensor. The performance of optical magnetic-field sensor is influenced by optical intensity change and wavelength change of light source, and phase shift so called optical bias mismatch. A magnetic field measuring system based on optical Faraday sensor is implemented and tested in the current range from 10 ampere to 200 ampere. The test result shows implemented system has goof linearity.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.541-546
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• 2012

This study investigates the detection system of oil pollution level using single optical fiber sensor. This study focus on sensing of oil pollution by moisture and iron powder which are representatives of oil pollution factor. In addition, It is placed that the water and iron powder as an oil pollution factor in the oil tank which is the oil circulation in. The oil pollution detection system was measured by the changing of intensity of light and sensing gap. The result of this experimentation not only confirmed the contamination by moisture volume in the oil tank from the section 190ppm to 540ppm, but also monitored the contamination by iron volume from the section 1200ppm to 3500ppm. This study confirmed effectiveness of this detection system using optical fiber sensor. There is expectations of measuring another section by various optical fiber sensor.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.160-169
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• 2018

Background: This study aims to develop an integrated optical system that can simultaneously or selectively measure the signals obtained from radioluminescence (RL), thermoluminescence (TL), and optically stimulated luminescence (OSL), which are luminescence phenomena of materials stimulated by radioactivity, heat, and light, respectively. The luminescence mechanism of various materials could be investigated using the glow curves of the luminescence materials. Materials and Methods: RL/TL/OSL integrated measuring system was equipped with a X-ray tube (50 kV, $200{\mu}A$) as an ionizing radiation source to irradiate the sample. The sample substrate was used as a heating source and was also designed to optically stimulate the sample material using various light sources, such as high luminous blue light emitting diode (LED) or laser. The system measured the luminescence intensity versus the amount of irradiation/stimulation on the sample for the purpose of measuring RL, TL and OSL sequentially or by selectively combining them. Optical filters were combined to minimize the interference of the stimulation light in the OSL signal. A long-pass filter (420 nm) was used for 470 nm LED, an ultraviolet-pass filter (260-390 nm) was used for detecting the luminescence of the sample by PM tube. Results and Discussion: The reliability of the system was evaluated using the RL/OSL characteristics of $Al_2O_3:C$ and the RL/TL characteristics of LiF:Mg,Cu,Si, which were used as dosimetry materials. The RL/OSL characteristics of $Al_2O_3:C$ showed relatively linear dose-response characteristics. The glow curve of LiF:Mg,Cu,Si also showed typical RL/OSL characteristics. Conclusion: The reliability of the proposed system was verified by sequentially measuring the RL characteristics of radiation as well as the TL and OSL characteristics by concurrent thermal and optical stimulations. In this study, we developed an integrated measurement system that measures the glow curves of RL/TL/OSL using universal USB-DAQs and the control program.