• 제목/요약/키워드: a optical sensor

검색결과 1,790건 처리시간 0.026초

Conceptual design and preliminary characterization of serial array system of high-resolution MEMS accelerometers with embedded optical detection

  • Perez, Maximilian;Shkel, Andrei
    • Smart Structures and Systems
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    • 제1권1호
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    • pp.63-82
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    • 2005
  • This paper introduces a technology for robust and low maintenance cost sensor network capable to detect accelerations below a micro-g in a wide frequency bandwidth (above 1,000 Hz). Sensor networks with such performance are critical for navigation, seismology, acoustic sensing, and for the health monitoring of civil structures. The approach is based on the fabrication of an array of high sensitivity accelerometers, each utilizing Fabry-Perot cavity with wavelength-dependent reflectivity to allow embedded optical detection and serialization. The unique feature of the approach is that no local power source is required for each individual sensor. Instead one global light source is used, providing an input optical signal which propagates through an optical fiber network from sensor-to-sensor. The information from each sensor is embedded onto the transmitted light as an intrinsic wavelength division multiplexed signal. This optical "rainbow" of data is then assessed providing real-time sensing information from each sensor node in the network. This paper introduces the Fabry-Perot based accelerometer and examines its critical features, including the effects of imperfections and resolution estimates. It then presents serialization techniques for the creation of systems of arrayed sensors and examines the effects of serialization on sensor response. Finally, a fabrication process is proposed to create test structures for the critical components of the device, which are dynamically characterized.

Palladium-based Electrical and Optical Hydrogen Gas Sensors

  • Jinwoo, Lee;Minah, Seo
    • 센서학회지
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    • 제31권6호
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    • pp.397-402
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    • 2022
  • In this short review, we explore the recent progress in metal-based gas-sensing techniques. The strong interaction between the metal films and hydrogen gas can be considered to play a considerably important role in the gas-sensing technique. The physical and chemical reactions in Pd-Pd hydride systems were studied in terms of the phase transition and lattice expansion of the metals. Two types of represented detection, electrical and optical, were introduced and discussed along with their advantages.

운전자 졸음 방지용 플라스틱 광섬유 센서 (Plastic Optical Fiber Sensor for an Anti-Drowsy Driving)

  • 엄원대;여상두;박재희
    • 한국ITS학회 논문지
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    • 제7권6호
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    • pp.133-139
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    • 2008
  • 본 논문에서는 플라스틱 광섬유 센서가 운전자의 졸음 방지용 센서로서 응용 가능한 지에 관하여 논의된다. 졸음방지용 플라스틱 광섬유 센서는 광섬유의 구부림이 잘 유도될 수 있도록 소프트한 물질로 덮개를 씌운 핸들에 플라스틱 광섬유가 감겨져 여는 구조로 되어져 있다. 운전자가 핸들을 잡을 때 운전자가 핸들에 힘을 가하게 되고 이 힘이 플라스틱 광섬유의 구부림을 유도하여 플라스틱 광섬유 내부를 진행하는 빛의 양을 감소시킨다. 실험 결과로부터 핸들에 가해지는 힘이 크면 클수록 검출되는 광량이 적어짐을 보여주어 졸음 방지용 센서로서의 사용할 수 있음을 검증해 보인다.

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광 마우스 센서를 이용한 이동로봇 좌표추정 (Coordinate Estimation of Mobile Robot Using Optical Mouse Sensors)

  • 박상형;이수영
    • 제어로봇시스템학회논문지
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    • 제22권9호
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    • pp.716-722
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    • 2016
  • Coordinate estimation is an essential function for autonomous navigation of a mobile robot. The optical mouse sensor is convenient and cost-effective for the coordinate estimation problem. It is possible to overcome the position estimation error caused by the slip and the model mismatch of robot's motion equation using the optical mouse sensor. One of the simple methods for the position estimation using the optical mouse sensor is integration of the velocity data from the sensor with time. However, the unavoidable noise in the sensor data may deteriorate the position estimation in case of the simple integration method. In general, a mobile robot has ready-to-use motion information from the encoder sensors of driving motors. By combining the velocity data from the optical mouse sensor and the motion information of a mobile robot, it is possible to improve the coordinate estimation performance. In this paper, a coordinate estimation algorithm for an autonomous mobile robot is presented based on the well-known Kalman filter that is useful to combine the different types of sensors. Computer simulation results show the performance of the proposed localization algorithm for several types of trajectories in comparison with the simple integration method.

An embedded vision system based on an analog VLSI Optical Flow vision sensor

  • Becanovic, Vlatako;Matsuo, Takayuki;Stocker, Alan A.
    • 한국정보기술응용학회:학술대회논문집
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    • 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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    • pp.285-288
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    • 2005
  • We propose a novel programmable miniature vision module based on a custom designed analog VLSI (aVLSI) chip. The vision module consists of the optical flow vision sensor embedded with commercial off-the-shelves digital hardware; in our case is the Intel XScale PXA270 processor enforced with a programmable gate array device. The aVLSI sensor provides gray-scale imager data as well as smooth optical flow estimates, thus each pixel gives a triplet of information that can be continuously read out as three independent images. The particular computational architecture of the custom designed sensor, which is fully parallel and also analog, allows for efficient real-time estimations of the smooth optical flow. The Intel XScale PXA270 controls the sensor read-out and furthermore allows, together with the programmable gate array, for additional higher level processing of the intensity image and optical flow data. It also provides the necessary standard interface such that the module can be easily programmed and integrated into different vision systems, or even form a complete stand-alone vision system itself. The low power consumption, small size and flexible interface of the proposed vision module suggests that it could be particularly well suited as a vision system in an autonomous robotics platform and especially well suited for educational projects in the robotic sciences.

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배전자동화 개폐기 내장형 광 전류 및 광 전압 센서에 관한 연구 (A Study on Optical Current Sensor and Voltage Sensor for automation of power distribution)

  • 양승국;오상기;박해수;김인수;김요희;홍창희
    • 한국정보통신학회논문지
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    • 제6권1호
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    • pp.89-98
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    • 2002
  • 본 연구에서는 광계측 기술을 이용하여 배전자동화 개폐기 내에서 발생하는 전자 계측장치의 절연문제 및 측정오차의 문제점을 개선하기 위하여 배선자동화개폐기 내장형 광전류 및 광전압센서를 연구하였다. 자기광학 효과(magneto optic effect)인 페러데이효과(Faraday effect)를 이용하여 최적의 광전류 센서를 설계 제작하여 높은 전류까지 선형성을 유지시키고 다른 상의 전류에 대한 유도현상을 최소로 하기 위해 순철 코아를 사용하여 광전류 센서를 일체화시켜 설계 제작하였다. 설계내에서 결정의 굴절률 및 방위각의 변화에 의해 생기는 전기광학효과(electrooptic effect)인 포켈스 효과(pockels effect)를 이용하여 광전압센서를 구성하였으며 배전 자동화용 개폐기의 협소한 내부구조를 고려하여 공간전계방식을 채택하였다. 또한 다심의 광섬유를 개폐기와 외부의 신호처리 단말기와 연결하기 위하여 기밀형 멀티 광커넥터를 설계 자작하여 접속 손실 및 가스 누설 시험을 하였다. 전기적 특성시험에서 광 전류센서에서는 인가 전류에 대한 선형 특성은 20A 에서 700A까지 변동 오차 2.5% 이내의 선형성을 유지하였으며, 광전압센서에 있어서 인가 전압에 대한 선형 특성은 6.6kV에서 19.8kV까지 거의 변동 오차가 1% 이내로 우수한 선형 특성을 나타냈다.

위성용 다중대역광학센서의 광학 성능 향상을 위한 자중보상기법 (Gravity Compensation Techniques for Enhancing Optical Performance in Satellite Multi-band Optical Sensor)

  • 윤도희
    • 한국군사과학기술학회지
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    • 제27권2호
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    • pp.127-139
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    • 2024
  • This paper discusses a gravity compensation technique designed to reduce wavefront error caused by gravity during the assembly and alignment of satellite multi-band optical sensor. For this study, the wavefront error caused by gravity was analyzed for the opto-mechanical structure of multi-band optical sensor. Wavefront error, an indicator of optical performance, was computed by using the displacements of optics calculated through structural analysis and optical sensitivity calculated through optical analysis. Since the calculated wavefront error caused by gravity exceeded the allocated budget, the gravity compensation technique was required. This compensation technique reduces wavefront error effectively by applying the compensation load to the appropriate position of the housing tube. This method successfully meets the wavefront error budget for all bands. In the future, a gravity compensation equipment applying this technique will be manufactured and used for assembly and alignment of multi-band optical sensor.

보상법을 적용한 광섬유 변위센서의 개발 (Development of Optical Fiber Coupled Displacement Probe Sensor with a New Compensation Method)

  • 김병준;김수현;이윤우;;;곽윤근
    • 한국정밀공학회지
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    • 제19권12호
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    • pp.27-32
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    • 2002
  • The intensity modulated type (reflective method) optical fiber sensor is a well -known method and widely applied to the displacement measurements and other industrial purposes. This type sensor has the advantages of relatively cheap cost, small sensor size and easiness of operation. The sensitivity of the sensor is very dependent of several error terms; the variation in the intensity of the light source and the changes in the surface reflectivity of the object. An optical fiber coupled displacement probe with a new compensation method is presented in this paper. The proposed displacement sensor can measure the displacements of the target surface independent of surface reflectivity error that is caused by the materials and surface processing grade.

팔라듐이 코팅된 단일모드 광섬유 센서를 이용한 수소 경보 시스템 구현 (Implantation of portable hydrogen alarm system based on palladium coated single mode optical fiber sensor)

  • 문남일;양병철;김광택;김태언
    • 센서학회지
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    • 제18권4호
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    • pp.269-273
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    • 2009
  • In this paper, a study on a portable hydrogen alarm system based on the palladium coated single mode fiber sensor has been reported. The fabricated hydrogen sensor exhibited 0.14 dB, 0.41 dB and 0.54 dB optical intensity variation when it was exposed by the nitrogen and hydrogen mixed gas containing 0.5 %, 1 % and 4 % of the hydrogen concentration, respectively. The fabricated sensor exhibited 20 second of response time and 120 second of recovery time for 4 % hydrogen containing gas. The fiber optics layout and software algorithm for detection of hydrogen leakage have been presented. The implanted portable hydrogen alarm system successfully generated an alarm signal when a 4 % hydrogen containing gas was leaked out.

Ultraviolet Light Sensor Based on an Azobenzene-polymer-capped Optical-fiber End

  • Cho, Hee-Taek;Seo, Gyeong-Seo;Lim, Ok-Rak;Shin, Woojin;Jang, Hee-Jin;Ahn, Tae-Jung
    • Current Optics and Photonics
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    • 제2권4호
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    • pp.303-307
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    • 2018
  • We propose a simple ultraviolet (UV) sensor consisting of a conventional single-mode optical fiber capped with an azobenzene-moiety-containing polymer. The UV light changes the dimensions of the azobenzene polymer, as well as the refractive index of the material. Incident light with a wavelength of 1550 nm was reflected at the fiber/polymer and polymer/air interfaces, and interference of the reflected beams resulted in spectral interference that shifted the wavelength by 0.78 nm at a UV input power of $2.5mW/cm^2$. The UV sensor's response to wavelength is nonlinear and stable. The response speed of the sensor is limited by detection noise, which can be improved by modifying the insertion loss of the UV sensor and the signal-to-noise ratio of the detection system. The proposed compact UV sensor is easy to fabricate, is not susceptible to electromagnetic interference, and only reacts to UV light.