• Title, Summary, Keyword: Optical reflectance

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Reflectance Characteristics of the Tobacco Leaves (잎담배의 광반사 특성)

  • Cho, H.K.;Kwon, Y.;Bang, S.H.
    • Journal of Biosystems Engineering
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    • v.19 no.3
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    • pp.247-257
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    • 1994
  • Optical properties of the tobacco leaves were determined. Surface colors and reflectance characteristics of the flue-cured variety and the Burley variety with thin and thick leaves were measured. Color was measured by CIE colorimeter and reflectance was measured with a laboratory built reflectance meter utilizing optical bandpass filters whose center wavelengths are from 400 to 700 nm at intervals of 50 nm. The resulting data indicated that the measured color and reflectance would be useful in inspecting tobacco. However no single optical data could be used to successfully grade tobacco leaves.

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Location of Sampling Points in Optical Reflectance Measurements of Chinese Cabbage and Kale Leaves

  • Ngo, Viet-Duc;Kang, Sin-Woo;Ryu, Dong-Ki;Chung, Sun-Ok;Park, Sang-Un;Kim, Sun-Ju;Park, Jong-Tae
    • Journal of Biosystems Engineering
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    • v.40 no.2
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    • pp.115-123
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    • 2015
  • Purpose: A sampling scheme may significantly affect the accuracy of a sensor. This study was conducted to investigate the effects of sampling point locations on optical reflectance measurements of Chinese cabbage and kale plant leaves. Methods: Variability and similarity of multiple measurements for different parts of the leaves were compared. Results: The results indicate that the variability between the average and individual reflectance spectra was smaller for the blade part than for the vein part. Furthermore, the reflectance for the blade part over the upper leaf area was greater and more stable than those for the other parts for both the cabbage and kale leaf samples. Conclusions: The results provide guidelines for optical reflectance measurements of Chinese cabbage and kale plants. The effects of the number of sampling points, the number of leaves, and the relationships between optical reflectance and leaf components remain to be investigated in the future.

An analysis method of reflectance spectra of strongly correlated electron systems

  • Hwang, Jungseek
    • Progress in Superconductivity and Cryogenics
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    • v.15 no.1
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    • pp.14-18
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    • 2013
  • We introduce a generic method to analyze optical 17reflectance spectra of strongly correlated electron systems including high-temperature superconductors by using an extended Drude model and Allen's approach. We explain the process step by step from reflectance through the optical conductivity and the scattering rate to the bosonic spectral function. Through the process we are able to get important information on the interactions between charge carriers from measured optical conductivity of the strongly correlated electron systems including copper oxide and iron pnitide high temperature superconductors.

A Study of Optical Property in PDP Using 3D Optical Code (3차원 광학시뮬레이션을 사용한 PDP의 광학적 특성에 관한 연구)

  • Kang, Jung-Won;Park, Hyun-Myung
    • Journal of the Semiconductor & Display Technology
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    • v.9 no.3
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    • pp.71-74
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    • 2010
  • In this study the optical properties, such as relative transmittance and reflectance of PDP were analyzed with 3D optical code. Because of the electrode structure, the reference model shows 21.3 % higher transmittance than the test model and the reference model shows 16.6 % higher reflectance than the test model. The calculated reflectance of reference and test models is compared to the measured reflectance and the difference between calculation and measurement is 4.9 %.

ESTIMATION OF PHOTOSYNTHETIC LIGHT USE EFFICIENCY IN A SINGLE LEAF BY ANALYZING NARROW-BAND SPECTRAL REFLECTANCE

  • Suh, Kyehong
    • Journal of Photoscience
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    • v.7 no.4
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    • pp.139-142
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    • 2000
  • To examine applicability of some optical indices from reflectance to estimate photosynthetic light use efficiency, photosynthesis, and narrow band spectral reflectance were simultaneously measured at various intensities of light with mongolian oak leaves. Narrow band of the broad-band NDVI was better than photochemical reflectance index and simple ratio to estimate photosynthetic light use efficiency in this study. Changes in spectral reflectance were detected at several wavelengths (540nm, 690nm, 740nm, and 800nm) associated with physiological status of plant leaves that could be components for new optical indices.

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Estimation of Forest LAI in Close Canopy Situation Using Optical Remote Sensing Data

  • Lee, Kyu-Sung;Kim, Sun-Hwa;Park, Ji-Hoon;Kim, Tae-Geun;Park, Yun-Il;Woo, Chung-Sik
    • Korean Journal of Remote Sensing
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    • v.22 no.5
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    • pp.305-311
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    • 2006
  • Although there have been several attempts to estimate forest LAI using optical remote sensor data, there are still not enough evidences whether the NDVI is effective to estimate forest LAI, particularly in fully closed canopy situation. In this study, we have conducted a simple correlation analysis between LAI and spectral reflectance at two different settings: 1) laboratory spectral measurements on the multiple-layers of leaf samples and 2) Landsat ETM+ reflectance in the close canopy forest stands with fieldmeasured LAI. In both cases, the correlation coefficients between LAI and spectral reflectance were higher in short-wave infrared (SWIR) and visible wavelength regions. Although the near-IR reflectance showed positive correlations with LAI, the correlations strength is weaker than in SWIR and visible region. The higher correlations were found with the spectral reflectance data measured on the simulated vegetation samples than with the ETM+ reflectance on the actual forests. In addition, there was no significant correlation between the forest.LAI and NDVI, in particular when the LAI values were larger than three. The SWIR reflectance may be important factor to improve the potential of optical remote sensor data to estimate forest LAI in close canopy situation.

Optical Characteristics of Bimetallic Silver-Gold Film Structure in Surface Plasmon Resonance Sensor Applications (표면 플라즈몬 공명 센서에서의 쌍금속 은-금 박막 구조의 광학 특성)

  • Gwon, Hyuk-Rok;Lee, Seong-Hyuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.1
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    • pp.156-160
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    • 2007
  • Surface plasmon resonance(SPR) has been widely studied for biological and chemical sensing applications. The present study conducts numerical simulation for the single and bimetallic layer SPR configurations by using the multiple beam interference matrix(MBIM) method to investigate the influence of wave interference and complex refractive indices of materials on optical characteristics such as reflectance and optical phase shift which are used for sensing. First, calculated reflectances are compared with experimental data for validation. In addition, in the single film structures this study finds out the appropriate film thicknesses with minimum reflectance for cases of gold film and silver film. For a bimetallic silver-gold film structure, in particular, the bimetallic film thicknesses that has the minimum reflectance are found 36 nm for silver and 5 nm for gold. From the results, the use of phase shift would be useful compared to reflectance in determining the SPR configuration because the phase shift becomes more sensitive than reflectance.

Dependence of Microstructure and Optical Properties of Ag-In-Sb-Te Phase-Change Recording Thin Firms on Annealing Heat-Treatments (열처리 조건에 따른 Ag-In-Sb-Te 상변화 기록 박막의 미세 조직과 반사도의 관계)

  • Seo, H.;Park, J. W.;Choi, W. S.;Kim, M. R.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.9-14
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    • 1996
  • The dependence of microstructural and optical properties of Ag-In-Sb-Te thin films on annealing heat-treatments was studied. It was found from the present work that the increase of reflectance after annealing heat-treatment is related with phase change of Ag-In-Sb-Te thin film from amorphous state to crystalline phases which involve Sb crystalline phase and AgInTe$_2$ stoichiometric phase. On the other hand, the reflectance is decreased after high temperature annealing (above 450$^{\circ}C$), due to the morphology .mange of film surface. For the purpose of practical application(erasable optical disk), we fabricated quadrilayered Ag-In-Sb-Te alloy disk, and annealed it with continuous laser beam. As result of this laser\ulcorner annealing treatment, we found that the increment of reflectance is 9.3% at 780nm wavelength. It might be considered that Ag-In-Sb-Te alloy optical disk is the big promising candidate for the erasable optical memory medium.

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ESTIMATION OF IOP FROM INVERSION OF REMOTE SENSING REFLECTANCE MODEL USING IN-SITU OCEAN OPTICAL DATA IN THE SEAWATER AROUND THE KOREA PENINSULA

  • Moon, Jeong-Eon;Ahn, Yu-Hwan;Ryu, Joo-Hyung;Yang, Chan-Su
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.224-227
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    • 2006
  • For estimation of three inherent optical properties (IOPs), the absorption coefficients for phytoplankton ($a_{ph}$) and suspended solid particle ($a_{ss}$) and dissolved organic matter ($a_{dom}$), from ocean reflectance, we used inversion of remote sensing reflectance model (Ahn et al., 2001) at this study. The IOP inversion model assumes that (1) the relationship between remote sensing reflectance ($R_{rs}$) and absorption (a) and backscattering ($b_{b}$) is well known, (2) the optical coefficients for pure water ($a_{w}$, $b_{bw}$) are known, (3) the spectral shapes of the specific absorption coefficients for phytoplankton ($a^*_{ph}$) and suspended solid particle ($a^*_{ss}$) and the specific backscattering coefficients for phytoplankton ($b_b^*_{ph}$) and suspended solid particle ($b_b^*_{ss}$) are known. The input data of IOP inversion model is used in-situ ocean optical data at the seawater around the Korea Peninsula for 5 years (2001-2005). We compared the output data of the IOP inversion model and the in-situ observation for seawater around the Korea Peninsula.

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