• 대한임베디드공학회논문지
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• 제14권6호
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• pp.295-311
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• 2019

The smart product market is growing year by year and is being used in many areas. There are various ways of interacting with smart products and users by inputting voice recognition, touch and finger movements. It is most important to detect an accurate hand region as a whole step to recognize hand movement. In this paper, we propose a method to detect accurate hand region in real time in various environments. A conventional method of detecting a hand region includes a method using depth information of a multi-sensor camera, a method of detecting a hand through machine learning, and a method of detecting a hand region using a color model. Among these methods, a method using a multi-sensor camera or a method using a machine learning requires a large amount of calculation and a high-performance PC is essential. Many computations are not suitable for embedded systems, and high-end PCs increase or decrease the price of smart products. The algorithm proposed in this paper detects the hand region using the color model, corrects the problems of the existing hand detection algorithm, and detects the accurate hand region based on various experimental environments.

• 센서학회지
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• 제21권3호
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• pp.211-216
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• 2012

Fires are the most common disaster and early fire detection is of great importance to minimize the consequent damage. Simple sensors including smoke detectors are widely used for the purpose but they are able to sense fires only at close proximity. Recently, due to the rapid advances of relevant technologies, vision-based fire sensing has attracted growing attention. In this paper, a novel visual sensing technique to automatically detect fire is presented. The proposed technique consists of multiple steps of image processing: pixel-level, block-level, and frame level. At the first step, fire flame pixel candidates are selected based on their color values in YIQ space from the image of a camera which is installed as a vision sensor at a fire scene. At the second step, the dynamic parts of flames are extracted by comparing two consecutive images. These parts are then represented in regularly divided image blocks to reduce pixel-level detection error and simplify following processing. Finally, the temporal change of the detected blocks is analyzed to confirm the spread of fire. The proposed technique was tested using real fire images and it worked quite reliably.

• Current Optics and Photonics
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• 제4권5호
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• pp.428-433
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• 2020

Recently, the on-chip autofocus (AF) function has become essential to the CMOS image sensor. An auto-focus usually operates using phase detection of the photocurrent difference from a pair of AF pixels that have focused or defocused. However, the phase-detection method requires a pair of AF pixels for comparison of readout. Therefore, the pixel variation may reduce AF performance. In this paper, we propose a color-selective AF pixel with a plasmonic nanostructure in a 0.9 μ㎡ pixel. The suggested AF pixel requires one pixel for AF function. The plasmonic nanostructure uses metal-insulator-metal (MIM) stack arrays instead of a color filter (CF). The color filters are formed at the subwavelength, and they transmit the specific wavelength of light according to the stack period and incident angles. For the optical analysis of the pixel, a finite-difference time-domain (FDTD) simulation was conducted. The analysis showed that the MIM stack arrays in the pixels perform as an AF pixel. As the primary metric of AF performance, the resulting AF contrasts are 1.8 for the red pixels, 1.6 for green, and 1.5 blue. Based on the simulation results, we confirmed the autofocusing performance of the MIM stack arrays.

• 한국전자통신학회논문지
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• 제18권5호
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• pp.919-926
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• 2023

본 논문에서는 주야간 움직임 감지 시스템 개발을 위한 주야간 촬영이 가능한 카메라 시스템을 구현하였다. 이를 위해 CMOS 이미지 센서는 물론 IR-LED를 이용하여 야간에도 선명한 영상 캡처가 가능하도록 설계하였다. 또한 칼라모델 분리를 통해 비교적 단순한 움직임 감지 알고리즘을 제안하였다. 칼라모델에서 H채널만 추출한 후, 영상을 블럭으로 나눈 다음 연속 프레임간의 평균 색상값을 이용하여 블록 매칭방식을 적용함으로써 움직임을 감지할 수 있다. 촬영 중 움직임이 감지되면 자동으로 경보음이 울리면서 화면을 캡처하여 PC에 저장할 수 있는 주야간 움직임 감지 시스템을 구현하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.768-773
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• 2011

Today's urban transit system is regarded as the important public transportation service which saves passengers' time and provides the safety. Many researches focus on the rapid and protective responses that minimize the losses when dangerous situation occurs. In this paper we proposed the early fire detection and corresponding rapid response method in urban transit system by combining automatic fire detection for video input and the sensor system. The fire detection method consists of two parts, spark detection and smoke detection. At the spark detection, the RGB color of input video is converted into HSV color and the frame difference is obtained in temporal direction. The region with high R values is considered as fire region candidate and stepwise fire detection rule is applied to calculate its size. At the smoke detection stage, we used the smoke sensor network to secure the credibility of spark detection. The proposed system can be implemented at low prices. In the future work, we would improve the detection algorithm and the accuracy of sensor location in the network.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3212-3216
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• 2010

A new rhodamine-based sensor 1 was designed and synthesized by incorporating rhodamine B and benzimidazole moieties. Sensor 1 exhibits high selectivity and sensitivity to $Cu^{2+}$ in $CH_3CN$-water solution (HEPES buffer, pH = 7.0) with an obvious color change from colorless to pink. Other metal ions such as $Hg^{2+}$, $Ag^+$, $Pb^{2+}$, $Sr^{2+}$, $Ba^{2+}$, $Cd^{2+}$, $Ni^{2+}$, $Co^{2+}$, $Fe^{2+}$, $Mn^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $Ce^{3+}$, $Mg^{2+}$, $K^+$ and $Na^+$ had no such color change and have no significant influence on $Cu^{2+}$ recognition process. The interaction of $Cu^{2+}$ and sensor 1 was proven to adopt a 1:1 binding stoichiometry and the recognition process is reversible.

• Korean Chemical Engineering Research
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• 제49권4호
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• pp.393-399
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• 2011

지난 수십년 동안, 환경오염물질에 대한 광학적 전기화학적 검출 방법에 관한 다양한 연구가 진행되었다. 최근에는 저렴하고, 장치가 불필요한 육안 식별 가능한 환경색센서가 개발되고 있다. 시각적 정성분석은 대상물질에 대한 즉각적인 정보를 제공하여, 실시간 현장 분석이 가능하게 해준다. 또한 정량분석이 가능한 색센서에 대한 관심도 높아지고 있다. 환경색센서는 기상의 VOC, 액상의 중금속 분석용으로 주로 개발되고 있다. 이에 본 총설에서는 다양한 환경색센서의 활용분야를 살펴보고, 기존 색센서의 문제점을 파악한 다음 환경색센서 기술의 발전방향에 관하여 전망하였다.

• 대한기계학회논문집A
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• 제39권1호
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• pp.105-109
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• 2015

고출력 레이저에 의한 영상 센서의 손상 분석 연구를 수행하였다. 고출력 레이저에 의한 금속의 손상에 관한 연구는 많이 이루어져 있지만, 상대적으로 고출력 레이저에 취약한 영상 시스템의 손상 연구는 미비한 상태이다. 본 논문에서는 CMOS 영상 센서에 고출력 레이저가 조사 되었을 때, 영상 센서가 받는 손상에 대해 실험적으로 분석하였다. 고출력 레이저 소스로는 근적외선대역의 연속발진 광섬유 레이저를 사용하였으며, 레이저 세기와 조사시간에 따른 CMOS 영상 센서의 영구적 손상 및 영상 품질을 분석하였다. 그 결과 조사시간과 레이저세기가 증가함에 따라 먼저 색상 손상이 나타나고 이후 작동불능 상태가 되었으며, 이러한 손상은 조사시간보다 레이저 세기에 더 큰 영향을 받는 것으로 나타났다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.182-185
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• 2005

Satellite cameras are calibrated before launch in detail and in general, but it cannot be guaranteed that the geometry is not changing during launch and caused by thermal influence of the sun in the orbit. Modem satellite imaging systems are based on CCD-line sensors. Because of the required high sampling rate the length of used CCD-lines is limited. For reaching a sufficient swath width, some CCD-lines are combined to a longer virtual CCD-line. The images generated by the individual CCD-lines do overlap slightly and so they can be shifted in x- and y-direction in relation to a chosen reference image just based on tie points. For the alignment and difference in scale, control points are required. The resulting virtual image has only negligible errors in areas with very large difference in height caused by the difference in the location of the projection centers. Color images can be related to the joint panchromatic scenes just based on tie points. Pan-sharpened images may show only small color shifts in very mountainous areas and for moving objects. The direct sensor orientation has to be calibrated based on control points. Discrepancies in horizontal shift can only be separated from attitude discrepancies with a good three-dimensional control point distribution. For such a calibration a program based on geometric reconstruction of the sensor orientation is required. The approximations by 3D-affine transformation or direct linear transformation (DL n cannot be used. These methods do have also disadvantages for standard sensor orientation. The image orientation by geometric reconstruction can be improved by self calibration with additional parameters for the analysis and compensation of remaining systematic effects for example caused by a not linear CCD-line. The determined sensor geometry can be used for the generation? of rational polynomial coefficients, describing the sensor geometry by relations of polynomials of the ground coordinates X, Y and Z.

• 한국정보통신학회논문지
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• 제6권2호
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• pp.364-370
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• 2002

본 논문에서 일반 지폐 계수기에 권종구분 기능과 복수장 검출기능 그리고 위조지폐판별기 능을 부가시킨 지폐계수기를 구현하였다 권종구분에는 센서 신호처리기술, 위조지폐 판별에는 센서응용기술 및 정보처리 기술을 사용하였고, 고속계수에는 정밀기구설계 기술과 마이크로프로센서 응용기술을 사용하였다. 소프트웨어는 RTOS를 기반으로 한 C 언어를 사용하여 효과적인 제어 알고리즘과 실시간으로 신호를 처리함으로 써 디버깅 및 추가 하드웨어와의 접목이 어려운 점을 개선하였다. 센서 디바이스로는 하드웨어 비용절감과 처리속도를 감안하여 포토다이오드와 포토다이오드 응용제품, 그리고 자기저항센서를 사용하였다. 마이크로 콘트롤러는 Intel I8051 코어를 사용한 필립스사의 PCF 80C552-24를 사용하였다. 실험 결과 컬러복사 및 컬러 프린트로 만든 위폐가 잘 구분되는 것을 확인하였으며, 계수 중 이권종이 있을 경우 구분해 냄으로써 다른 지폐가 섞여 계수 되는 것을 방지 할 수 있었다.