• 제목/요약/키워드: Reflectance difference

검색결과 241건 처리시간 0.029초

Forest fire experiment toward the detection of forest fires using RS - Thermal and reflectance environment change observation at ground level -

  • Tanpipat, Veerachai;Honda, Kiyoshi
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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    • pp.690-695
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    • 2002
  • In this forest fire experiment the ThermoViewer was set up on the platform built on a tree and observed the temperature change, before, during and after the fire. The fire experiment had been carried out not only the day of the forest fire experiment but also continued for four months after the forest fire had been gone. The results from the experiment showed that the temperature difference is significant in the afternoon; therefore, afternoon satellite passing is better and suitable time for active forest fires and burnt scars detection; moreover, after 83 days, the burnt and un-burnt vegetation become almost the same condition, fully regenerated and the temperature difference become nearly 0$^{\circ}$ Celsius, so there is not enough temperature different between burnt and un-burnt vegetation for current sensors to distinguish the difference anymore.

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Reduction of reflection from PET (polyethylene terephthalate) film surface by natural plasma etching

  • Oh, Hoon;Song, Yu-Jin;Whang, Ki-Woong
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1419-1424
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    • 2006
  • We could reduce the reflection from PET(polyethylene terephthalate) film surface by natural plasma etching which does not use etch masks. The plasma etched PET film showed lower reflectance and higher transmittance which is resulted by making subwavelength structure(SWS) on the film surface by the plasma etch rate difference between the amorphous and crystalline region in the surface of PET film.

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Qualification of various polymorphs by near-infrared(NIR) spectrophotometer.

  • Lim, Hun-Rang;Chang, Soo-Hyun;Woo, Young-Ah;Kim, Hyo-Jin
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.400.2-400.2
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    • 2002
  • Near-infrared(NIR) reflectance spectroscopy was employed to qualify various ploymorphs. We collected 8 potential polymorphs forms of Medicine T for this study. Near-infared spectra of the powder samples contained in glass vials were obtained over the wavelength region of 1100-1750nm. There were the peak around 1560nm in the 6 spectra among 8 spectra. Principal component analysis(PCA) has been performed to examine the qualitative difference of 8 polymorphs PC space. (omitted)

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차열도료용 Cool Pigment 및 Paint 개발 (Development of IR Reflective Cool Pigment and Paint)

  • 권면주;도영웅;하진욱
    • 한국산학기술학회논문지
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    • 제13권8호
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    • pp.3800-3805
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    • 2012
  • 본 논문에서는 도심 열섬현상 방지 및 에너지 효율을 높이기 위하여 적외선 반사율이 30%이상인 건물 내 외장재용 흑색 차열안료 및 도료에 대한 연구를 하였다. 안료는 $Fe_2O_3$$Cr_2O_3$의 혼합원료를 $900{\sim}1,200^{\circ}C$에서 소성하여 합성하였으며, 도료는 합성한 안료에 아크릴수지와 기타첨가제를 사용하여 제조하였다. 연구결과, Cr과 Fe을 1:0.9 몰비로 혼합하여 $1,000^{\circ}C$에서 소성한 안료의 발색도가 가장 우수하였고, 차열안료 20%에 분산제 1.5%를 첨가하여 제조한 차열도료로 $125{\mu}m$ 두께의 도막을 형성시켰을 때 적외선 반사가 가장 우수하였다. 차열도료와 일반도료의 표면온도 차이는 $36.5^{\circ}C$로 나타났으며 700~2,500nm 파장대의 적외선 반사율(TSR)은 39.3%로 측정되었다. 또한, 500시간의 내후성 평가에서 색상변화는 거의 나타나지 않았다.

MODIS 영상을 이용한 빙하의 정규청빙지수(NDBI) 개발 및 변화요인 분석 (Development of Normalized Difference Blue-ice Index (NDBI) of Glaciers and Analysis of Its Variational Factors by using MODIS Images)

  • 한향선;지영훈;김연춘;이훈열
    • 대한원격탐사학회지
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    • 제30권4호
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    • pp.481-491
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    • 2014
  • 빙상이나 빙하, 빙붕에서 푸른색의 얼음이 지표에 노출되어 있는 지역을 청빙지대라 한다. 이는 빙하 표면에 쌓인 눈이 바람에 의해 침식되거나 기온과 일사량에 따른 승화로 인해 대부분 제거되기 때문이다. 청빙지대는 운석이 농집되기 쉽고 빙체의 질량균형에 매우 큰 영향을 미치기 때문에, 청빙의 노출도 및 밀집도에 대한 정량적 지표의 개발이 요구되고 있다. 이 연구에서는 2007~2012년에 동남극 맥머도 드라이벨리를 촬영한 MODIS 영상을 이용하여 청빙과 눈, 구름의 분광반사특성을 분석하고, 청빙의 노출도 및 밀집도를 정량화 할 수 있는 정규청빙지수(Normalized Difference Blue-ice Index, NDBI) 알고리즘을 고안하였다. 눈과 구름은 가시광선과 근적외선 파장대역에서 매우 높은 반사율을 나타낸다. 청빙은 청색 파장대역에서 높은 반사율을 보이는 반면에, 근적외선 파장대역에서 낮은 반사율을 보인다. NDBI 알고리즘은 청색과 근적외선 파장대역에서의 반사율 차이를 두 반사율의 합으로 나누는 것으로 표현된다[NDBI = (Blue - NIR)/(Blue + NIR)]. 청빙의 NDBI는 노출도와 밀집도에 따라 0.2~0.5의 값을 가지며, 0.2 이하의 값을 가지는 눈과 구름이나 음수의 값을 나타내는 암석으로부터 명확히 구분되었다. 청빙의 NDBI가 시간에 따라 변화하는 현상은 맥머도 드라이벨리의 기상관측소에서 측정된 풍속($R^2=0.012$)이나 기온($R^2=0.278$) 보다는 적설두께와 가장 높은 상관성($R^2=0.699$)을 나타냈다. 적설두께가 증가할수록 NDBI 값은 감소하였는데, 이는 청빙지대의 NDBI 값으로부터 적설량의 추정이 가능함을 의미한다. 이 연구에서 개발된 NDBI 알고리즘은 운석탐사, 빙체의 질량균형 분석, 적설량 추정 등 다양한 극지연구 분야에서 매우 유용하게 사용될 것으로 전망된다.

지용성 염료를 표지물로 사용한 인공오염포의 특성과 세척성에 판한 연구 (A Study on the Artificially Soiled Fabric Containing Oil Soluble Dye as an Indicator)

  • 박경원;김형균
    • 한국의류학회지
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    • 제21권1호
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    • pp.58-66
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    • 1997
  • In order to evaluate the exact effect of detergency it is necessary both to measure the actual soil content by chemical analysis and to determine the degree of soil removal visually. Since it takes considerable time and effort to use both methods, usually one of the two methods is used. Many studies have been carried out through increasing the visibility of oily soil to evaluate detergency by measuring reflectance of fabrics. In this study Sudan Black B, an oil soluble dye was used as an indicator to increase the visibility of oily soil on cotton and polyester fabrics. The condition of artificially soiled fabrics and the method of evaluating detergency were investigated which represent the actual detergency of oily soil by measuring the reflectance only. Also the detergency of Sudan Black B and that of oily soil were compared with each other under various washing conditions, As a result, the K/S values converted from the reflectances showed a good correlation with the actual soil content. Linear relationship between K/S value and the actual soil content was obtained. The K/S values of washed fabrics were higher than those of unwashed fabrics which included same content of soil since the soil visibility changed during washing. But the difference was small when Sudan Black B was used. With the increase of soil content, detergency of cotton fabric decreased, but detergency of polyester fabric increased gradually. With regards to soiled fabrics, detergency of cotton fabric measured by K/S value was close to that of actual oily soil when Sudan black B was used as an indicator.

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PET원사의 염착특성과 관련한 $TiO_2$ 함량, 원사의 강도 및 방사유제의 영향 (Effects of $TiO_2$ content, fiber strength and spinning oil on dyeing properties of the PET fibers)

  • 박영민;조대환;손영아
    • 한국염색가공학회지
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    • 제18권3호
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    • pp.10-15
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    • 2006
  • In this research, we studied the dyeing properties of PET fibers in terms of $TiO_2$ contents, fiber strength and spinning oil which may cause barre' effect. The effect of $TiO_2$ contents in the fibers had no influence on the dye uptake. However, the reflectance(%) behaviors showed the different visual properties as $TiO_2$ contents in the fibers. The other factors could be considered as strength and spinning oil which also revealed difference on the dye exhaustion. The experimental results showed that $TiO_2$ contents within the fibers influenced reflectance(%) behaviors. Furthermore, fiber strength and spinning oil could be considered other major factors to impart the dyeing irregularity and barre' effect.

Radiometric Characteristics of Geostationary Ocean Color Imager (GOCI) for Land Applications

  • Lee, Kyu-Sung;Park, Sung-Min;Kim, Sun-Hwa;Lee, Hwa-Seon;Shin, Jung-Il
    • 대한원격탐사학회지
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    • 제28권3호
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    • pp.277-285
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    • 2012
  • The GOCI imagery can be an effective alternative to monitor short-term changes over terrestrial environments. This study aimed to assess the radiometric characteristics of the GOCI multispectral imagery for land applications. As an initial approach, we compared GOCI at-sensor radiance with MODIS data obtained simultaneously. Dynamic range of GOCI radiance was larger than MODIS over land area. Further, the at-sensor radiance over various land surface targets were tested by vicarious calibration. Surface reflectance were directly measured in field using a portable spectrometer and indirectly derived from the atmospherically corrected MODIS product over relatively homogeneous sites of desert, tidal flat, bare soil, and fallow crop fields. The GOCI radiance values were then simulated by radiative transfer model (6S). In overall, simulated radiance were very similar to the actual radiance extracted from GOCI data. Normalized difference vegetation index (NDVI) calculated from the GOCI bands 5 and 8 shows very close relationship with MODIS NDVI. In this study, the GOCI imagery has shown appropriate radiometric quality to be used for various land applications. Further works are needed to derive surface reflectance over land area after atmospheric correction.

2종의 엽록소 측정기를 이용한 포장내 벼의 엽록소 함량 분포 측정 (Measurement of Variability of Chlorophyll Contents in Paddy Fields Using Two Kinds of Chlorophyll Meter)

  • 성제훈;서상룡;박우풍;정인규;김상철;이충근
    • Journal of Biosystems Engineering
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    • 제28권3호
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    • pp.245-252
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    • 2003
  • This study was investigated the possibility of measuring chlorophyll in paddy crops using two kinds of chlorophyll meters(SPAD-502, Field Scout). The results of correlation analysis showed the 0.7758(r$^2$) relationship between the chlorophyll contents of paddy leaves measured by SPAD and spectrophotometer. It indicates that chlorophyll content in paddy crops could be measured using the SPAD. Considering the data of the SPAD and Field Scout there was significant difference between their chlorophyll contents measured by the SPAD and Field Scout. Likewise, such results were consistent with the corrected data using light intensity. According to the results, it can be concluded that it is difficult to describe the rice chlorophyll measured by the Field Scout more accurately than the SPAD when using one standard spectrum and another spectrum for reflectance measuring. The chlorophyll variance measured at a research institute and a farmer's field revealed that the output of SPAD was more reliable than that of the Field Scout.

Design of Optical Biological Sensor for Phycocyanin Parameters Measurement using Fluorescence Technique

  • Lee, Sung Hwa;Mariappan, Vinayagam;Won, Dong Chan;Ann, Myungsuk;Yang, Seungyoun
    • International journal of advanced smart convergence
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    • 제5권2호
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    • pp.73-79
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    • 2016
  • Remote sensing and measurement are of paramount importance of providing information on the state of water quality in water bodies. The formation and growth of cyanobacteria is of serious concern to in land aquatic life forms and human life. The main cause of water quality deterioration stems from anthropogenic induced eutrophication. The goal of this research to quantify and determine the spatial distribution of cyanobacteria concentration in the water using remote sensing technique. The standard approach to measure water quality based on the direct measurement of the fluorescence of the chlorophyll a in the living algal cells and the same approach used to detect the phycobilin pigments found in blue-green algae (a.k.a. cyanobacteria), phycocyanin and phycoerythrin. This paper propose the emerging sensor design to measure the water quality based on the optical analysis by fluorescence of the phycocyanin pigment. In this research, we developed an method to sense and quantify to derive phycocyanin intensity index for estimating cyanobacteria concentrations. The development of the index was based on the reflectance difference between visible light band 620nm and 665nm. As a result of research this paper presents, an optical biological sensor design information to measure the Phycocyanin parameters in water content.