• 한국세라믹학회지
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• 제12권1호
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• pp.29-36
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• 1975

This study was conducted to research the formation, color development and application for colored glazes of the spinel solid solutions of the green pigment. On specimens prepared by calcining the oxide and basic carbonate mixture at 1250℃ for 1.5 hour, the x-ray analysis, measurement of reflectance and the test of their stabiality as a glaze pigment were carried out. The results are summarized as follows 1) Each sample is composed of single spinel and not of mixture of spinel. 2) Formation of continuous soild solution, except for a few instances, pertaining to Vegard's law was confirmed by means of the x-ray analysis. 3) The more difference between absorption and reflectance lies, the lighter colors are. When the absorption occurs at the high-reflectance, the excitation purity becomes low. On the contrary when the absorption takes place at the low-reflectance, the excitation purity becomes low. On the contrary when the absorption takes place at the low-reflectance, the excitation purity is higher. 4) Colors obtained in the CdO-MgO-Cr2O3-Al2O3 system, as the amounts of Al3+ increased, change from green through brown to pink, and the absorption peak shifts towards violet region. 5) An increase in Co2+ in the CoO-MgO-Cr2O3-Al2O3 system, changes the color from blue green to dark blue. The excitation purity is higher, and the absorption peak shifts toward regions. 6) Colors are green in the NiO-MgO-Cr2O3 and CdO-MgO-Cr2O3 systems in general, but in the ZnO-MgO-Cr2O3 system brillant hue is not obtained. 70 According to the results of the colored glaze test, the spinels turn outto be stable as brilliant glaze pigment in the calcium-magnesia glaze.

• 대한원격탐사학회지
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• 제26권6호
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• pp.653-664
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• 2010

The land surface reflectance is a key parameter influencing the climate near the surface. Therefore, it must be determined with sufficient accuracy for climate change research. In particular, the characteristics of the bidirectional reflectance distribution function (BRDF) when using earth observation system (EOS) are important for normalizing the reflected solar radiation from the earth's surface. Also, wide swath satellites like SPOT/VGT (VEGETATION) permit sufficient angular sampling, but high resolution satellites are impossible to obtain sufficient angular sampling over a pixel during short period because of their narrow swath scanning. This gives a difficulty to BRDF model based reflectance normalization of high resolution satellites. The principal objective of the study is to add BRDF modeling of high resolution satellites and to supply insufficient angular sampling through identifying BRDF components from SPOT/VGT. This study is performed as the preliminary data for apply to high-resolution satellite. The study provides surface parameters by eliminating BRD effect when calculated biophysical index of plant by BRDF model. We use semi-empirical BRDF model to identify the BRD components. This study uses SPOT/VGT satellite data acquired in the S1 (daily) data. Modeled reflectance values show a good agreement with measured reflectance values from SPOT satellite. This study analyzes BRD effect components by using the NDVI(Normalized Difference Vegetation Index) and the angle components such as solar zenith angle, satellite zenith angle and relative azimuth angle. Geometric scattering kernel mainly depends on the azimuth angle variation and volumetric scattering kernel is less dependent on the azimuth angle variation. Also, forest from land cover shows the wider distribution of value than cropland, overall tendency is similar. Forest shows relatively larger value of geometric term ($K_1{\cdot}f_1$) than cropland, When performed comparison between cropland and forest. Angle and NDVI value are closely related.

• 한국지형학회지
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• 제21권4호
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• pp.121-131
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• 2014

이 연구에서는 카올리나이트의 분광반사 특성과 ASTER(Advanced Spaceborne Thermal Emission and Reflectance Radiometer) 영상 자료를 이용하여 경상남도 하동지역 고령토 광산의 분포를 추출하였다. ASTER 영상의 광물별 파장 흡수 밴드특성을 이용하여 고령토 광상의 주 구성 광물인 카올리나이트의 분포 양상을 추출하기 위해서 밴드 비연산 모델을 적용하였다. 분광반사 특성 곡선에 따르면 카올리나이트는 Al-OH에 의해서 0.96과 $2.18{\mu}m$ 파장 인근에서 흡수특성이 나타나며, $1.24{\mu}m$와 $1.38{\sim}1.41{\mu}m$에서 OH의 영향을 받는다. 이러한 카올리나이트 분광특성을 ASTER 영상에 적용하여 현재 개발 중인 고령토 광산을 포함하여 채굴적 등의 분포를 판독하였다.

• 한국재료학회지
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• 제25권2호
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• pp.61-67
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• 2015

$Fe_2O_3$ coated plate mica($Fe_2O_3$/mica) for infrared reflectance red pigment was prepared under hydrothermal treatment. $Fe_2O_3$ was perfectly coated on mica via the difference of surface charge between $Fe_2O_3$ and mica particles at pH 3. $Fe_2O_3$/mica was then calcined at $800^{\circ}C$ to stabilize the coated layer on mica. The infrared(IR) reflectance pigments were characterized by X-ray diffraction, FE-SEM, zeta potential, and a UV-Vis-NIR spectrophotometer. In particular, the CIE color coordinate and IR reflectance properties of $Fe_2O_3$/mica pigments were investigated in relation to the thickness variation of the $Fe_2O_3$ layer coated on mica of various lateral sizes. The isolation-heat red paints containing the pigments were prepared and optimized with a thinner, settling agent, and dispersant. Then, the films were made. The thermal property of isolation-heat on these films was observed through the relationship of the IR reflectance value, which was based on the variation of the $Fe_2O_3$ layer's thickness coated on mica and mica's lateral size as IR reflectance pigment. With an increase in IR reflectance on these films, the thermal property of isolation-heat was effectively enhanced.

• 대한원격탐사학회지
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• 제36권5_1호
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• pp.735-747
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• 2020

본 연구는 청천일 조건에서 직접적 보정 방식으로 산정한 반사율 및 식생지수의 일주기 변화를 분석하여 시계열 작황 모니터링을 위한 무인비행체 영상의 특성을 구명하고자 수행하였다. 무인기에 다중분광센서를 장착하여 청천일이었던 2020년 3월 23일과 3월 24일에 반사율 보정용 반사판, 콘크리트 및 작물 시험구를 대상으로 시간대별, 비행경로별 항공영상을 촬영하여 직접적 방식으로 반사율을 산정하고 작물 시험구를 대상으로 식생지수를 계산하여 비교하였다. 반사율 보정용 반사판, 콘크리트 및 작물 시험구의 무인기 영상 반사율은 시간대 및 비행경로별로 일정한 변화 경향을 보이지 않을 뿐 아니라 일간 재현성 있는 값을 보이지 않아 시계열적으로 비교·활용 하는 것에는 한계가 있을 것으로 판단된다. 그러나 작물 시험구의 NDVI는 값이 높을수록 일중 및 일간 변동성이 적었으며 식생의 활력이 부족한 식생 제어 시험구에서도 일 중 5% 미만의 변동계수를 보여 반사율과 달리 대체로 일정한 값을 유지하는 것으로 나타났다. 또한 3월 23일과 3월 24일 동일한 시간대에 촬영한 무인기 영상으로 산정한 NDVI의 평균 절대 오차도 0.76~3.97%의 범위를 보여 시계열 작황모니터링에 활용이 가능할 것으로 판단된다.

• 대한원격탐사학회지
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• 제36권6_2호
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• pp.1523-1535
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• 2020

원격탐사를 이용한 작황정보 생산은 작물의 생물계절을 이용하여 작물 분류, 생육 모니터링, 생산량 추정 분석이 선행되어야 한다. 생물계절에 추정을 위한 시계열 영상 자료가 필요하지만 KOMPSAT(Korea Multi-Purpose Satellite)만으로 획득하는 것은 물리적 제한이 있으므로 타 지구관측위성과의 융합 활용이 필요하다. 위성자료의 융합 활용을 위해서는 각 위성이 가지는 고유의 방사학적 센서 특성 차이를 극복해야 한다. 본 연구는 위성자료의 융·복합 활용을 위한 첫 단계로서 KOMPSAT-3와 Landsat-8 위성의 교차검보정을 수행하였다. Libya-4 PICS(Pseudo Invariant Calibration Sites)에서 2년간 수집된 위성자료에 대해 초분광위성을 이용하여 산정된 SBAF(Spectral Band Adjustment Factor)를 적용하여 대기상단 반사도를 비교하였다. 교차검보정 결과 KOMPSAT-3와 Landsat-8 위성은 Blue, Green, Red 밴드에서 약 4%, NIR밴드에서 6%의 반사율 차이를 보였다. 온보드 켈리브레이터가 없는 KOMPSAT-3는 Ladnsat-8에 비해 Radiometric Stability가 낮은 것으로 나타났다. 향후 교차검보정의 정확도를 높이기 위해 BRDF(Bidirectional reflectance distribution function) 보정 및 지형보정을 통하여 정규화 된 반사율 자료를 생산하기 위한 노력이 필요하다.

• 한국안광학회지
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• 제5권1호
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• pp.31-37
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• 2000

제1~3색각 이상 검사용 Farnsworth Dichotomous Test Panel D-15의 칼라분석을 위하여 380~780 nm의 반사광 spectrum 세기를 측정하여 CIE system을 도입하였다. Panel D-15의 색상변환은 650nm 이상, 500~600 nm, 400~450 nm의 3개 파장영역의 광 반사율 세기에 의존한다. 반사 spectrum으로부터 3극치 X, Y, Z 값, 보색 평면과 명암축으로 하는 3차원 CIELAB system의 $L^*a^*b^*$와 Lab 값, CIELUV system $U^*V^*$ 값, 색도도 좌표 x, y 값을 구했다.

• 한국작물학회지
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• 제49권5호
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• pp.394-406
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• 2004

A split-plot designed experiment including four rice varieties and 10 nitrogen levels was conducted in 2003 at the Experimental Farm of Seoul National University, Suwon, Korea. Before heading, hyperspectral canopy reflectance (300-1100nm with 1.55nm step) and nine crop variables such as shoot fresh weight (SFW), leaf area index, leaf dry weight, shoot dry weight, leaf N concentration, shoot N concentration, leaf N density, shoot N density and N nutrition index were measured at 54 and 72 days after transplanting. Grain yield, total number of spikelets, number of filled spikelets and 1000-grain weight were measured at harvest. 14,635 narrow-band NDVIs as combinations of reflectances at wavelength ${\lambda}l\;and\;{\lambda}2$ were correlated to the nine crop variables. One NDVI with the highest correlation coefficient with a given crop variable was selected as the NDVI of the best fit for this crop variable. As expected, models to predict crop variables before heading using the NDVI of the best fit had higher $r^2$ (>10\%)$ than those using common broad- band NDVI red or NDVI green. The models with the narrow-band NDVI of the best fit overcame broad- band NDVI saturation at high LAI values as frequently reported. Models using NDVIs of the best fit at booting showed higher predictive capacity for yield and yield component than models using crop variables.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.420-423
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• 1997

The oxygen saturation of blood can be measured by sensing the difference absorption in optical spectra of Hb and $HbO_2$, as the well known previous study. [1] In this study we developed the noninvasive tissue reflectance oximeter(TRO) using three kinds of LEDs which produce a peak spectral emission at a wavelength of 565, 660 and 940nm. And we tested the unction of the TR oximeter by comparing the output signals measured on normal tissue to measured on low oxygenated tissue. The results showed that oxygen saturation of blood and biological tissue can be monitored from the separation arrangement light source and detector.

• 반도체디스플레이기술학회지
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• 제13권3호
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• pp.21-25
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• 2014

The texturing is one of the most important processes for high efficiency crystalline silicon solar cells. The rear side flatness of silicon solar cell is very important for increasing the light reflectance and forming uniform back surface field(BSF) region in manufacturing high efficiency crystalline silicon solar cells. We investigated texturing difference between front and rear side of wafer by texturing of two adhered wafers. As a result, the flatter rear side was obtained by forming less pyramid size compared to the front side and improved reflectance of long wavelength and back surface field(BSF) region were also achieved. Therefore, the texturing of two adhered wafers can be expected to improve the efficiency of silicon solar cells due to increased short circuit current(Isc).