• Journal of Advanced Marine Engineering and Technology
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• v.19 no.3
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• pp.9-23
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• 1995

To analyze the spray and flame in D.I. diesel engine, the visualizing methods by schlieren photograph and diffused background illumination photograph with high speed camera are applied to optically accessible D.I.diesel engine. Wcaporating spray, spray droplets and brightness flame are taken with high speed camera by visuallizing method in accordance with various suction air temperature and injection time. The spray and flame image on the film was analyzed by image analyzer. The optically accessible D.I. diesel engine had the similar pressure characteristic to the real D.I. diesel engine. Experimental results showed that shadow areas of the evaporating spray were extended at higher suction air temperature, spray droplets had a max. Penetration length and their penetrating patterns were dependent on the surrounding gas temperature, and flame size after ignition was largely governed by the evaporated fuel quantity at ignition point and by the surrounding gas condition due to piston motion.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.30-40
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• 1995

Optically accessible D. I. diesel engine with a rectangular combustion chamber was constructed to visualize the behaviors of sprays and flames in the combustion camber with the close conditions of pressure and temperature in an actual engine. The behaviors of sprays and flames in the combustion chamber as the operating conditions of this engine were photographed with high speed camera by Diffused Background Illumination Method. With photographs taken by this method, behavior of spray droplets injected into the combustion chamber, ignition points, and flame propagation were observed and analyzed at a time-and space-dependent fashion.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.167-173
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• 2015

Extraction of Finger-end points is one of the most process for user multi-commands in the Hand-Gesture interface technology. However, most of previous works use the geometric and morphological method for extracting a finger-end points. Therefore, this paper proposes the method of user finger-end points extraction that is motivated a ultrared diffused illumination, which is used for the user commands in the multi-touch display device. Proposed air-mouse is worked by the quantity state and moving direction of extracted finger-end points. Also, our system includes a basic mouse event, as well as the continuous command function for expending a user multi-gesture. In order to evaluate the performance of the our proposed method, after applying to the web browser application as a command device. As a result, the proposed method showed the average 90% success-rate for the various user-commands.

• Journal of ILASS-Korea
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• v.10 no.3
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• pp.17-28
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• 2005

The Holographic Particle Velocimetry system can be a promising optical tool for the measurements of three dimensional particle velocities. In this study, diffused illumination holographic system to measure the sizes and 3D velocities of moving particles based on automatic image processing was developed. First of all basic optical systems for pulse laser recording, continuous laser reconstruction, and image acquisition, were constructed. To determine the position of particles in the optical axis, new three auto-focusing parameters(AEP), namely, Correlation Coefficient, Sharpness Index, and Depth Intensity were introduced and verified. The developed system was applied to spray droplets to validate the capability of the system. Three dimensional positions of particles viewed from two sides were decided using AFP and then 3D velocities of Particles were extracted by particle tracking algorithm. Comparison of measurement results of sizes and 3D velocities of particles with those obtained by laser instrument, PDPA, showed good consistency of the developed holographic system.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.353-354
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• 2009

최근 사용자의 다중 입력이 가능한 멀티 터치(Multi-Touch) 기술은 HCI(Human Computer Interaction) 분야에서 가장 주목 받고 있는 기술 가운데 하나이다. 그러나 이러한 터치 기술은 입력 장치에 의존적이기 때문에 공간적 제약의 문제를 지니고 있다. 따라서 본 논문에서는 멀티 터치 디스플레이 장치에서 사용자 입력 처리를 위해서 사용되는 확산 투광(DI: Diffused illumination)방식을 이용하여 사용자 입력에 있어서 공간적 제약이 없는 공간 마우스를 구현한다. 제안하는 공간 마우스는 기본적인 마우스 이벤트 처리뿐만 아니라 확장된 사용자 멀티 제스쳐를 위한 성능 향상 방안을 제시한다. 구현된 공간 마우스는 윈도우 어플리케이션 사용 환경에 적용한 결과 성공적인 결과를 보였다.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.1
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• pp.13-18
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• 2010

Most of the research in the multi-touch area is based on the FTIR(Frustrated Total Internal Re리ection), which is just implemented by using the previous approach. Moreover, there are not the software solutions to improve a performance in the multi touch-blobs detection or the user gesture recognition. Therefore, we implement a multi-touch table-top display that is based on the DI(Diffused Illumination), the improved touch-points detection and user gesture recognition. The proposed method supports a simultaneous transformation multi-touch command for objects in the running application. Also, the system latency time is reduced by the proposed ore-testing method in the multi touch-blobs detection processing. Implemented device is simulated by programming the Flash AS3 application in the TUIO(Tangible User Interface Object) environment that is based on the OSC(Open Sound Control) protocol. As a result, Our system shows the 37% system latency reduction, and is successful in the multi-touch gestures recognition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.4 s.247
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• pp.287-297
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• 2006

The Holographic Particle Velocimetry system can be a promising optical tool for the measurements of three dimensional particle velocities. One of inherent limitations of particle holography is the very long depth of field of particle images, which causes considerable difficulty in the determination of particle positions in the optical axis. In this study, we introduced three auto-focusing parameters corresponding to the size of particles, namely, Correlation Coefficient, Sharpness Index, and Depth Intensity to determine the focal plane of a particle along the optical axis. To investigate the suitability of the above parameters, the plane image of dot array screens containing different size of dots was recorded by diffused illumination holography and the positions of each dot in the optical axis were evaluated. In addition, the effect of particle position from the holographic film was examined by changing the distance of the screen from the holographic film. All measurement results verified that the evaluated positions using suggested auto-focusing parameters remain within acceptable range of errors. These research results may provide fundamental information for the development of the holographic velocimetry system based on the automatic image processing.

• Korean Journal of Optics and Photonics
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• v.31 no.4
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• pp.183-190
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• 2020

In this paper, the illuminating optics of asymmetric light distribution was studied, which allowed the light distribution to be uniform even for short-range irradiation on a wide illumination area. In the case of a light installed at a short distance, the light is not diffused enough because of the short irradiation distance. For this reason, it is difficult to satisfy uniformity of illumination. In addition, lighting design for asymmetric distribution is required because the lighting device is installed tilted, for visibility. Therefore, the design of lighting systems with asymmetric light distribution could achieve uniform illumination of the target surface even under short-distance irradiation. This was then applied to the license lamp, a lighting system featuring short light irradiation distance, to confirm that it satisfies the legal standards.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.156-164
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• 1998

Electronic Speckle Pattern Interferometry(ESPI) has been used to measure surface deformations of engineering components and materials in industrial areas. ESPI, a non-contact and non-destructive technique, is capable of providing full-field results with high spatial resolution and high speed. One of the important application using electronic speckle pattern interferometry is electronic speckle contouring of a diffused object for 3-D shape analysis and topography measurement. Generally the electronic speckle contouring is suitable for providing measurement range from millimeters to several centimeters. In this study, we introduce the contouring method by modified dual-beam speckle pattern interferometer and the shift of the two illumination beams through optical fiber in order to obtain the contour fringe patterns. We also describe formation process of depth contour fringes and grid contour fringes by shifting direction of the two illumination beams. Before the experiments, we performed the geometric analysis for dual-beam-shifted ESPI contouring, and then, the electronic speckle contouring experiment with various specimens. For quantitative analysis of the contour fringes, we used 4-frame phase shifting method with PZT Finally, good agreement between the geometric analysis and experimetal results is obtained.

• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.283-290
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• 1999

The $n^+/p/p^+$ junction PERL solar cell of $0.1{\sim}2{\Omega}{\cdot}cm$ (100) p type silicon wafer was fabricated through the following steps; that is, wafer cutting, inverted pyramidally textured surfaces etching by KOH, phosphorus and boron diffusion, anti-reflection coating, grid formation and contact annealing. At this time, the optical characteristics of device surface and the efficiency of doping concentration for resistivity were investigated. And diffusion depth and doping concentration for n+ doping were simulated by silvaco program. Then their results were compared with measured results. Under the illumination of AM (air mass)1.5, $100\;mW/cm^2$ $I_{sc}$, $V_{oc}$, fill factor and the conversion efficiency were 43mA, 0.6 V, 0.62. and 16% respectively.