• Title, Summary, Keyword: 광도계

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Realization of the national standard of candela traceable to the absolute cryogenic radiometer at KRISS (극저온 절대복사계에 소급한 칸델라 국가표준 실현)

  • Park, Seung-Nam;Kim, Yong-Wan;Lee, Dong-Hoon
    • Korean Journal of Optics and Photonics
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    • v.15 no.5
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    • pp.443-448
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    • 2004
  • We realized the national standard of the candela, one of the SI units, by using two photometers with the spectral responsivity measured in reference to the absolute cryogenic radiometer. The external apertures of the photometers were fabricated using a diamond turning machine, and measured in terms of area with uncertainty of 0.05 %(k = 1). The candela is realized using a 1 kW FEL lamp and the characterized photometers on an optical bench. The uncertainty is budgeted to be 0.25 %(k = 1) considering the uncertainty of the spectral responsivity and the response uniformity of the detectors, the area of the external apertures, the color temperature of the lamp, and the positioning reproducibility of the photometers and the lamp. We verified the realized scale by comparing with the scale of National Institute of Standards and Technology, USA. They coincided with each other within 0.1%.

우리나라 패류의 계절에 따른 중금속 오염도 변화

  • 김정민;권훈정;김찬국;이창복
    • Proceedings of the Korean Society of Toxicology Conference
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    • pp.86-86
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    • 2003
  • 국내에서 식용되고 있는 패류 내의 중금속 오염도를 검색하기 위하여 5, 6, 7, 8, 10, 12월 동안 12종, 70개의 시료를 수집하였다. 젖은 시료 약 3g에 질산과 과산화수소를 가하여 마이크로파 분해 장치로 습식분해하고 희석하여 ICP-MS, 원자흡광 광도계, 원자 형광 광도계로 분석 하였다. 분석 원소는 Hg, Pb, Cd, As를 포함하여 13종이며 계절에 따른 중금속 오염도의 변화양상을 보았다. (중략)

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Geometric and Photometric Distortion Correction Method for Low Cost Digital Cameras (저가형 디지털 카메라 적용을 위한 기하학적 왜곡 및 광도 왜곡 보정 방법)

  • 유원필;정연구
    • Proceedings of the Korean Information Science Society Conference
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    • pp.205-207
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    • 2003
  • 본 논문에서는 카메라 렌즈에서 흔히 발견할 수 있는 렌즈계 왜곡에 의한 영상 품질 저하 현상을 소개하고 이를 보정하는 방법을 제시한다. 렌즈계 왜곡은 크게 두 가지로 나눌 수 있는데 기하학적 왜곡과 광도 왜곡이 그것이다. 이상적인 렌즈계가 아닌 경우 이러한 왜곡 현상은 필연적으로 발생을 하게 되는데 왜곡 보정을 위해서 기존의 카메라 캘리브레이션과는 다른 방식의 접근이 필요하게 된다. 본 논문에서는 기하학적 왜곡 보정을 위한 이미지 워핑 방법을 제시하며 아울러 광도 왜곡 보정을 위한 보정 방법을 다루고자 한다.

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Polychromatic OTF measurement of an optical system using a white light source (백색광원을 이용한 광학계의 polychromatic OTF 측정)

  • Song, Jong-Sub;Lee, Yoon-Woo;Cho, Hyun-Mo;Lee, In-Won;Cho, Jae-Heung;Jang, Soo;Im, Chun-Seok
    • Proceedings of the Optical Society of Korea Conference
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    • pp.82-83
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    • 2001
  • 카메라, 망원경 등의 일반 광학제품 뿐만 아니라 야시경, 열상장비 등의 적외선 결상장치, 수중이나 항공기에서 사용되는 첨단 광학기기들은 종류나 용도가 아주 다양하여 사용목적에 적합한 광학계를 설계하거나 새로운 광학계를 개발하기 위해서는 그 성능을 정확하게 평가하는 것이 매우 중요하다. 현재까지 많은 경우에 있어서 렌즈나 광학계는 다색광원(polychromatic illuminant)에서 사용되도록 설계되어 지고 있고 또한 광학계를 통해 맺혀지는 상도 색감각을 갖는 반응체(사람의 눈, 필름 등)에 의해 평가되어 진다. (중략)

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Oil Fluorescence Spectrum Analysis for the Design of Fluorimeter (형광 광도계 설계인자 도출을 위한 기름의 형광 스펙트럼 분석)

  • Oh, Sangwoo;Seo, Dongmin;Ann, Kiyoung;Kim, Jaewoo;Lee, Moonjin;Chun, Taebyung;Seo, Sungkyu
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.18 no.4
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    • pp.304-309
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    • 2015
  • To evaluate the degree of contamination caused by oil spill accident in the sea, the in-situ sensors which are based on the scientific method are needed in the real site. The sensors which are based on the fluorescence detection theory can provide the useful data, such as the concentration of oil. However these kinds of sensors commonly are composed of the ultraviolet (UV) light source such as UV mercury lamp, the multiple excitation/emission filters and the optical sensor which is mainly photomultiplier tube (PMT) type. Therefore, the size of the total sensing platform is large not suitable to be handled in the oil spill field and also the total price of it is extremely expensive. To overcome these drawbacks, we designed the fluorimeter for the oil spill detection which has compact size and cost effectiveness. Before the detail design process, we conducted the experiments to measure the excitation and emission spectrum of oils using five different kinds of crude oils and three different kinds of processed oils. And the fluorescence spectrometer were used to analyze the excitation and emission spectrum of oil samples. We have compared the spectrum results and drawn the each common spectrum regions of excitation and emission. In the experiments, we can see that the average gap between maximum excitation and emission peak wavelengths is near 50 nm for the every case. In the experiment which were fixed by the excitation wavelength of 365 nm and 405 nm, we can find out that the intensity of emission was weaker than that of 280 nm and 325 nm. So, if the light sources having the wavelength of 365 nm or 405 nm are used in the design process of fluorimeter, the optical sensor needs to have the sensitivity which can cover the weak light intensity. Through the results which were derived by the experiment, we can define the important factors which can be useful to select the effective wavelengths of light source, photo detector and filters.

Development of relative radiometric calibration system for in-situ measurement spectroradiometers (현장관측용 분광 광도계의 상대 검교정 시스템 개발)

  • Oh, Eunsong;Ahn, Ki-Beom;Kang, Hyukmo;Cho, Seong-Ick;Park, Young-Je
    • Korean Journal of Remote Sensing
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    • v.30 no.4
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    • pp.455-464
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    • 2014
  • After launching the Geostationary Ocean Color Imager (GOCI) on June 2010, field campaigns were performed routinely around Korean peninsula to collect in-situ data for calibration and validation. Key measurements in the campaigns are radiometric ones with field radiometers such as Analytical Spectral Devices FieldSpec3 or TriOS RAMSES. The field radiometers must be regularly calibrated. We, in the paper, introduce the optical laboratory built in KOSC and the relative calibration method for in-situ measurement spectroradiometer. The laboratory is equipped with a 20-inch integrating sphere (USS-2000S, LabSphere) in 98% uniformity, a reference spectrometer (MCPD9800, Photal) covering wavelengths from 360 nm to 1100 nm with 1.6 nm spectral resolution, and an optical table ($3600{\times}1500{\times}800mm^3$) having a flatness of ${\pm}0.1mm$. Under constant temperature and humidity maintainance in the room, the reference spectrometer and the in-situ measurement instrument are checked with the same light source in the same distance. From the test of FieldSpec3, we figured out a slight difference among in-situ instruments in blue band range, and also confirmed the sensor spectral performance was changed about 4.41% during 1 year. These results show that the regular calibrations are needed to maintain the field measurement accuracy and thus GOCI data reliability.

Humidity Sensor using Polyvinylpyrrolidone-Coated Mach-Zehnder Interferometer in Planar Lightwave Circuit (폴리비닐피롤리돈이 코팅된 마하젠더 간섭계 기반의 평판형 광도파로 습도센서)

  • Kim, Ju Ha;Kim, Myoung Jin;Jung, Eun Joo;Hwang, Sung Hwan;Lee, Woo Jin;Choi, Eun Seo;Rho, Byung Sup
    • Korean Journal of Optics and Photonics
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    • v.24 no.5
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    • pp.251-255
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    • 2013
  • In this paper, the characteristics of a humidity sensor implemented by Mach Zehnder Interferometer (MZI) in a Planar Lightwave Circuit (PLC) have been designed and demonstrated. The humidity outside is detected with polyvinylpyrrolidone (PVP) coated on the etched arm of the MZI. The length of the etched arm is 10 mm and the PVP was coated by dip-coating into the etched region. As the refractive index of the PVP changes with the surrounding humidity, the PVP-coated humidity sensor presented changes in the interferogram depending on RH (Relative Humidity) around the PLC. The measured results show that the proposed humidity sensor works successfully in the range of 30% to 80% of RH.

MTF and wavefront error testing of large aperture optical system using unequal path interferometer (경로길이 불일치 간섭계를 이용한 대구경 광학계의 MTF 측정과 파면오차 검사)

  • Song, Jong-Sup;Jo, Jae-Heung;Lee, Yun-Woo;Song, Jae-Bong;Yang, Ho-Soon;Lee, In-Won
    • Korean Journal of Optics and Photonics
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    • v.16 no.1
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    • pp.50-55
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    • 2005
  • A method for measuring the wavefront error and the modulation transfer function(MTF) of large aperture optics using an unequal path interferometer is presented. A bidirectional shearing interferometer is used for collimation testing of the measurement system. A large aperture Fizeau interferometer with long optical path difference measures the wavefront error of the optics under test by using a $\Phi$ 400 mm off-axis parabolic mirror. The MTF is also measured at the wavelength of the interferometer by changing the laser light into partially incoherent light. Test results of a $\Phi$ 300 mm Cassegrain type satellite telescope made in Korea are presented.

Design Spectrophotometer for Blocking the $2^{nd}$ diffracted Light (2차 회절광 차단을 위한 분광 광도계 설계)

  • 홍영주;곽윤근;김수현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.875-880
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    • 2004
  • Stray light is the light except the light of the analytic wavelength and the source of measurement error of absorbance. Some experimental results showed that diffractive grating is the major factor of stray light in spectrophotometer. Through the ray tracing with the software tool, classified the paths of the diffractive light from grating and found the range of wavelength which reach the exit slit. The quantity of the stray light(0.025%) is more than the minimum limit of stray light(0.01%) of the single monochromator. A novel optical layout design method, which prevent the reflected rays entering the diffractive grating is proposed.

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