• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.26-34
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• 1999

This study shows an alternative method for the determination of object's position, based on a computer vision method. This approach develops the vision system model to define the reciprocal relationship between the 3-D real space and 2-D image plane. The developed model involves the bilinear six-view parameters, which is estimated using the relationship between the camera space location and real coordinates of known position. Based on estimated parameters in independent cameras, the position of unknown object is accomplished using a sequential estimation scheme that permits data of unknown points in each of the 2-D image plane of cameras. This vision control methods the robust and reliable, which overcomes the difficulties of the conventional research such as precise calibration of the vision sensor, exact kinematic modeling of the robot, and correct knowledge of the relative positions and orientation of the robot and CCD camera. Finally, the developed vision control method is tested experimentally by performing determination of object position in the space using computer vision system. These results show the presented method is precise and compatible.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.513-516
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• 2006

인터넷의 발달로 인터넷 사용자는 기하급수적으로 증가하게 되었으며, 인터넷을 기반으로 하는 수많은 응용프로그램들이 개발되고 있다. 인터넷상에는 수많은 사이트(site)들이 존재하며 방문자들의 주목을 받기 위하여 여러 가지 기법을 선보이고 있다. 그러나 컴퓨터상의 정적인 2차원 평면하에서는 현실감 및 입체감을 경험하는 것이 한계가 있다. 따라서 플래시(flash)와 같은 플러그인(plug-in) 및 동영상을 도입하여 동적인 컨텐츠를 제공하는 사례가 늘고 있으며 한편으로 최근 가상현실(Virtual Reality) 기법을 이용한 사이트들이 점차 증가하고 있는 추세이다. 가상현실은 컴퓨터가 제공하는 3차원의 컴퓨터 그래픽 기술을 이용하여 사용자와 온라인으로 상호대화를 하는 기법이라고 간단히 정의할 수 있다[2,3]. 가상현실을 이용하여 3차원 실시간 구현 기술을 웹에 적용시킴으로서 3차원 공간에서 현실감을 느낄 수 있게 함과 동시에 입체적인 정보를 사용자에게 제공할 수 있게 하는 기법들이 속속 선보이게 되었다. 현재 다양한 인터넷 기반 3차원 가상 현실 기술이 각각 서로 다른 기술 및 특징들을 가지고 나와 있다. 3차원 가상 공간을 구현한다. 선택한 물체에 사진 이미지기반 방식과 3차원 모델링 방식을 모두 적용하여 보다 현실감 있고 모든 방향으로의 접근이 가능하도록 하며. 또한 3차원 사운드 및 동영상도 함께 제공하며 가상 공간과 인간의 실질적 교감을 현실화 시키는 인터페이스를 제시하는 데에 연구의 목적이 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.157-160
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• 2007

Spray characteristics of an injector employed in liquid rocket engine is investigated by Particle Image Velocimetry and Dual-mode Phase Doppler Anemometry measurements. Instantaneous plane images captured by PIV technique are examined in order to judge a pass-fail criteria of spray injection performance. DPDA technique is also applied in order to measure the velocity and diameter of spray droplets. The eternal objective of this study is to evaluate an injector performance which may be utilized for the design of brand-new ones through the clear understanding of spray characteristics.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.13-17
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• 2004

In order to measure the retina thickness, the retina photographing system and the multi-channel high speed image data acquisition system is developed. This system requires the optical processing techniques and the high speed image processing techniques. The HeNe laser beam is projected the retina in artificial eye and then we sensed the reflected laser signal using APD array. The laser projection system on retina using optical instruments is implemented. In order to project the plane laser beam on retina, laser photographing system used the polygon mirror for horizontal scanning and the galvano mirror for vertical scanning. We acquired retina images in each channel of APD array, transferred computer using PCI interface the image data after real-time A/D converting.

• Journal of Digital Contents Society
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• v.16 no.5
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• pp.835-847
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• 2015

Photo scanning can create point cloud and polygon models like 3D scanners bringing an object into the 3 dimensional world by combining several sheets of photographic information. The created data give us information about planes and sectional forms required for a 2 dimensional survey as well as 3 dimensional figures of buried cultural property. It requires a lot of time to record buried cultural property in the field, however, the photo scanning technique does not need additional equipment and manpower so the work may begin immediately while the property is protected. Moreover, it reduces financial burdens as it creates 3 dimensional data using images acquired by photography but provides the optimal condition to check 3 dimensional information quickly and easily.

• Geophysics and Geophysical Exploration
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• v.4 no.3
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• pp.89-95
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• 2001

The final goal of the seismic method is to verify the spatial characteristic of subsurface media. For this purpose, professional interpreters interprete the discontinuities of seismic events from seismic image. This paper introduces a method for automatic discontinuity extraction from 3D seismic image. The method consists of three steps. The first step is for estimating coherency of seismic events from seismic data. The second step is to express the potential region where discontinuities may exist in the form of binary image. The third step is to locate the discontinuities by thining the region found in the second step.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.270.2-270.2
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• 2013

직선운동하는 하전입자의 진행방향에 수직한 평면상에 서로 직교하는 전기장과 자기장을 걸어주면, 하전입자에는 전기장에 의한 힘 FE와 자기장과 속도 v에 의한 로렌츠력 $F_B=q(v{\times}B)$가 동시에 작용하게 된다. 이때 Wien 조건 FB=-FE를 만족하는 질량 mA과, 에너지 EA를 가지는 하전입자 A는 휘지 않고 직선운동을 계속하나, 하전입자 A와 다른 에너지 $E_B\;(=E_A+{\delta}E)$나 질량 $m_B\;(=m_A+{\delta}m)$을 가지는 하전입자는 휘게 되며, 그 휘는 정도는 ${\delta}E$나 ${\delta}m$에 비례하게 된다. 이 현상을 이용하여 다양한 종류의 에너지 또는 질량 분석기가 독일, 미국, 일본 등의 분석기기 선진국에서 개발되어 왔고, 전자현미경의 이미지 필터로도 활용되고 있으며, 통상 EXB 필터 또는 발명자의 이름을 딴 Wien 필터로 불리어지고 있다. $E{\times}B$ 필터는 일반적인 하전입자빔 렌즈와 다른 광학특성을 가지며, 지난 발표에서는 $E{\times}B$ 필터의 기본 궤도 방정식 및 다양한 2차 기하 수차 방정식의 유도과정 및 결과를 보여주었다. 본 발표에서는 EXB 필터의 전후에 배치시켜, 초점거리 등의 조정을 수행할 4극자와, $E{\times}B$ 필터에서 발생하는 2차 수차의 보정을 수행할 6극자의 광학특성의 계산 결과를 보여준다. 4극자-6극자-EXB필터-6극자-4극자 조합의 기본 광학궤도 계산 결과는 빔 다이어그램으로 보여준다. 6극자에 의해 수차를 줄여서 향상되는 에너지 분해능 값은 수치적으로 추정한다. 실제 제작이 된 각 부품의 외형 및 사진을 보여주어 에너지 필터의 제작 진행 상황을 보고한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.3
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• pp.50-57
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• 2007

Spray characteristics of an injector in a small liquid rocket engine (LRE) is characterized by Particle Image Velocimetry (PIV) and Dual-mode Phase Doppler Anemometry (DPDA). Instantaneous plane images captured by PIV are examined for the qualitative prediction of spray breakup with the setup of evaluation technique for effect of spray angles on injector performance. DPDA is also applied in order to quantify the average velocity, turbulent intensity, SMD, and number density of spray droplets along the spray stream distance leading to precise observation of spray atomization behavior. An objective of the study is the derivation of design parameters of new injectors and the establishment of performance criteria through the clear understanding of spray characteristics.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.3
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• pp.31-39
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• 2011

The flowfield in a solid rocket motor was simulated at the wall-injection test model, which has a fin-slot grain and submerged nozzle, and visualized by a smoke-wire. The high speed CCD camera captured the visualized images around the nozzle inlet through the grain center port. The vortical tube structure and circumferential flow patterns at the nozzle throat were visualized. The radial momentum transfer caused by the shear-interactions of slot-outlet flow, fin-base flow and grain port flow from upstream worked as the source of these phenomena.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.2
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• pp.124-131
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• 2019

This study presents an imaging algorithm that can provide an image of a moving target in a multiple-input-multiple-output radar environment where multiple transmitting and receiving radars are fixed on the ground. The proposed algorithm, which is based on polar format processing using plane wave approximation, is shown to provide an unaliased image by using multiple transmitting radars even when the distances between the receiving radars are relatively large. We derive the conditions necessary to deploy the transmitting radars by which the resolution of the reconstructed image can be improved, while simultaneously reducing aliasing artifacts. Moreover, we offer a means of separating out each transmitting radar target echo. Finally, the performance of the proposed system is verified through a simulation.