• 문화기술의 융합
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• 제8권6호
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• pp.953-958
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• 2022

홀로그래픽 스테레오그램은 여러 시점에서 취득한 다수의 이미지를 사용하므로 입체피로나 어지러움 없는 입체감을 제공한다. 홀로그래픽 스테레오그램을 제작하기 위해서는 실사 물체의 다시점 투영 이미지를 획득한 후 디지털 홀로그램 프린터를 이용해 필름에 기록하는 과정을 거쳐야 한다. 다시점 투영 이미지(Perspective Images)를 획득할 때, 대상 물체와 카메라 사이의 거리가 일정해야 왜곡 없는 홀로그램을 제작할 수 있다. 대상 물체가 소형이면카메라와의 거리를 일정하게 유지하는 것이 가능하지만, 대형인 경우에는 물체와 카메라와의 일정 거리 유지가 어렵다. 본 논문에서는 대형 물체의 홀로그램 제작에 필요한 다시점 투영 이미지를 획득하기 위해, 드론을 이용하여 스마트 비행 모드인 POI(Point of Interest)방법으로 촬영하였다. 이후, 예기치 못한 흔들림이나 대상 물체와의 거리가 일정하지 못한 부분은 후반에서의 작업을 통해 문제점을 보정하는 단계를 거쳐 대형 물체의 다시점 투영 이미지를 제작하였다.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.692-709
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• 2006

Nucleate pool boiling experiments with constant wall temperature were performed using pure R1l3 for subcooled, saturated, and superheated pool conditions. A microscale heater array and Wheatstone bridge circuits were used to maintain the constant wall temperature and to measure the instantaneous heat flow rate accurately with high temporal and spatial resolutions. Images of bubble growth were taken at 5,000 frames per second using a high-speed CCD camera synchronized with the heat flow rate measurements. The bubble geometry was obtained from the captured bubble images. The effect of the pool conditions on the bubble growth behavior was analyzed using dimensionless parameters for the initial and thermal growth regions. The effect of the pool conditions on the heat flow rate behavior was also examined. This study will provide good experimental data with precise constant wall temperature boundary condition for such works.

• 한국도로학회논문집
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• 제7권4호
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• pp.185-202
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• 2005

본 연구에서는 현장 실험 조성의 제약을 극복하기 위해 3차원 가상현실(virtual reality)로 설계중인 도로를 모델링한 후, 피실험자가 Eye camera가 장착된 차량 시뮬레이터 (driving simulator)에 탑승하고 주행하면서 운전자가 행하는 선형변화에 대한 동적 반응 및 운전자의 시각행태에 대한 데이터를 획득하였다 본 실험에 적용된 차량시뮬레이터의 그래픽 모듈은 동역학 해석 모듈에 의해 얻어진 데이터를 기초로 하여 운동재현기와 가상환경의 일치감들 최대로 함으로써 피실험자로 하여금 차량시뮬레이터의 비현실성 및 부작용을 최소화하도록 하였다. 또한, Eye camera는 기존의 여타 장비와는 달리 운전자가 헬멧이나 렌즈 등 어떠한 부착장치도 착용하지 않고 실험할 수 있는 FaceLAB을 사용함으로써 운전자의 자연스러운 시각행태를 아무런 데이터 손실없이 획득하였다. 본 연구에서는 조사된 데이터를 바탕으로 도로 안전성을 평가하기 위해 차량 시뮬레이터, Eye camera방법을 통해 설계시 도로 기하구조 변화에 따라 운전자가 느끼는 안전성의 변화를 파악함으로써 도로 기하구조 조건과 안전성의 상관성을 명확하게 규명하고 이를 통해 운전자가 도로 주행시 편안하고 쾌적한 주행을 보장받을 수 있는 도로를 설계 단계에서부터 평가할 수 있는 방법을 제시하려고 한다.

• 한국전자통신학회논문지
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• 제9권2호
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• pp.155-160
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• 2014

본 논문에서 RGB-Depth 카메라를 이용하여 실내에서의 연기를 검출하는 알고리즘을 제안한다. RGB-Depth 카메라는 RGB 색영상과 깊이 정보를 제공한다. 키넥트(Kinect)는 특정한 패턴의 적외선을 출력하고 이를 적외선 카메라로 수집하고 분석하여 깊이 정보를 획득한다. 특정한 패턴을 구성하는 점들 각각에 대하여 거리를 측정하고 객체면의 깊이를 추정한다. 따라서, 이웃하는 점들의 깊이 변화가 많은 객체인 경우에는 객체면의 깊이를 결정하지 못한다. 연기의 농도가 일정 주파수로 변화하고, 적외선 영상의 이웃하는 화소간의 변화가 많기 때문에 키넥트가 깊이를 결정하지 못한다. 본 논문에서는 연기에 대한 키넥트의 특성을 이용하여 연기를 검출한다. 키넥트가 깊이를 결정하지 못한 영역을 후보영역으로 설정하고, 색영상의 밝기가 임계값보다 큰 경우 연기영역으로 결정한다. 본 논문에서는 시뮬레이션을 통하여 실내에서의 연기 검출에 RGB-Depth 카메라가 효과적임을 확인할 수 있다.

• 핵의학기술
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• 제27권1호
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• pp.36-41
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• 2023

Purpose The long-term trend of extrinsic uniformity by type of gamma camera was analyzed, and the factors affecting uniformity were investigated. Based on this, the purpose was to predict the life of the gamma camera, pay attention to factors that affect uniformity, and obtain better quality images. Materials and methods Four of the gamma cameras in operation at a senior general hospital in Seoul were selected and the trend of extrinsic uniformity from the first operation date to the present was analyzed. In order to minimize various factors affecting uniformity, a detailed analysis was conducted by calculating the monthly and annual average of the uniformity values. Results Two Symbia E gamma cameras from SIEMENS, one Symbia Evo Excel gamma camera, and one Symbia Intevo16 gamma camera were selected and analyzed. The uniformity of Symbia E₁ (2012 warehousing) changed unevenly, and the uniformity of Symbia E₂ (2014 warehousing) changed according to the replacement cycle of ⁵⁷Co sheet sources. The uniformity of Symbia Evo Excel (received in 2017) and Symbia Intevo 16 (received in 2017) was constant compared to Symbia E. Conclusion The extrinsic uniformity of the gamma camera gradually increased over time. However, there was a difference in uniformity for each type of gamma camera, and there was a change in uniformity in which the cause could not be accurately identified. In order to improve the quality of the image, it is necessary to periodically check changes in uniformity and minimize factors that affect uniformity.

• 제어로봇시스템학회논문지
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• 제13권9호
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• pp.896-902
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• 2007

This paper proposes a vision-based kinematic control method for mobile robots with camera-on-board. In the previous literature on the control of mobile robots using camera vision information, the forward velocity is set to be a constant, and only the rotational velocity of the robot is controlled. More efficient motion, however, is needed by controlling the forward velocity, depending on the position in the corridor. Thus, both forward and rotational velocities are controlled in the proposed method such that the mobile robots can move faster when the comer of the corridor is far away, and it slows down as it approaches the dead end of the corridor. In this way, the smooth turning motion along the corridor is possible. To this end, visual information using the camera is used to obtain the perspective lines and the distance from the current robot position to the dead end. Then, the vanishing point and the pseudo desired position are obtained, and the forward and rotational velocities are controlled by the LOS(Line Of Sight) guidance law. Both numerical and experimental results are included to demonstrate the validity of the proposed method.

• 한국기계가공학회지
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• 제20권2호
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• pp.101-106
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• 2021

In this paper, an inspection system has been developed where pneumatic instruments are used to stretch the film using compressed air, thus the curl problem can be overcome. When the pneumatic system is applied, a line scan camera should be used instead of an area camera because the COF surface makes an arc by the air pressure. The distance between the COF and the inspection camera should be kept constant to get a clear image, thus the position of COF is to be monitored on real-time. An operating software has been also developed which is switching on/off the pneumatic system, determining the COF position using a camera vision, displaying the contour of the COF side view, sending self-diagnosis result and etc. The developed system has been examined using the actual roll of COF, which convince that the system can be an effective device to inspect the COF rolls in process.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.48-57
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• 2003

A cylindrical constant volume combustion chamber was used to investigate the flow characteristics at spark plug and the combustion characteristics of homogeneous charge methane-air mixture under various initial pressure, excess air ratio and ignition times in quiescent mixture. The flow characteristics such as mean velocity and turbulence intensity was analyzed by hot wire anemometer. Combustion pressure development measured by piezoelectric pressure transducer and flame propagation acquired by ICCD camera were used to investigate the effect of initial pressure, excess air ratio and ignition times on pressure, combustion duration, flame speed and burning velocity. Mean velocity and turbulence intensity had the maximum value at 200 or 300ms and then decreased to near 0 value gradually after 3 seconds. Combustion duration, flame speed and burning velocity were observed to be promoted with excess air ratio of 1.1, lower initial pressure and ignition time of 300ms.

• 전기학회논문지
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• 제56권7호
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• pp.1261-1267
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• 2007

Although LEDs have been used in various applications with improving the brightness and luminous efficacy, the electrical and optical characteristics of high power LED varies at different temperature and starting time. In this paper, optimal heat sink and apparatus design were conducted using IR camera and ICEPAK on the LED bulb consisting with fourteen LED array. The temperatures of heat sink and LED device of the designed LED bulb without cooling pan were $74^{\circ}C\;and\;96.8^{\circ}C$, respectively, showing in good themal characteristics. For high efficiency driving circuit of LED array adopted optimal heat sink design, driving circuits of constant voltage and current circuits were suggested and fabricated. As a result the efficacy of all driving circuits showed more than 20 lm/W. Also, the constant current circuits are suitable for signal lamp, hallway lamp, and flash lamp having short operating time(about 30 min). On the other hand, a reading light and indoor lamp having long operating time can be controlled by constant voltage circuit.

• Journal of Advanced Marine Engineering and Technology
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• 제21권3호
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• pp.302-310
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• 1997

In this paper, we find a method to improve ignitability using methanol which is prospective as an alternative fuel. The constant volume combuster is divided into main chamber and sub-cham¬ber. These two chambers are linked by an adapter which is shaped like a cup. We also compare CDI to HIS that is revised in our laboratory for making a scrutiny into the effects of ignition char¬acteristics. Besides, we analyze a flame propagation process in the main and sub-chamber through taking pictures 10, 000 frames per second by high speed camera at the state being fabricated quartz glass aside main and sub-chamber.