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- 주제어 : multi-spectral reflectance (검색결과 4 건)
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Multi-spectral Reflectance of Warm-Season Turfgrasses as Influenced by Deficit Irrigation
이준희,Laurie E. Trenholm,J. Bryan Unruh 한국잔디학회 2008 Weed & Turfgrass Science Vol.22 No.1
Remote sensing using multispectral radiometry may be a useful tool to detect drought stress in turf. The objective of this research was to investigate the correlation between drought stress and multispectral reflectance (MSR) from the turf canopy. St. Augustinegrass (Stenotaphrum secundatum[Walt.] Kuntze.) cultivars ‘Floratam’ and ‘Palmetto’, ‘SeaIsle 1’ seashore paspalum (Paspalum vaginatum Swartz.), ‘Empire’ zoysiagrass (Zoysia japonica Steud.), and ‘Pensacola’ bahiagrass (Paspalum notatumFlugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at 100%, 80%, 60%, or 40% of evapotranspiration (ET). Weekly evaluations included: a) shoot quality, leaf rolling, leaf firing b) soil moisture, chlorophyll content index; c) photosynthesis and d) multispectral reflectance. All the measurements were correlated with MSR data. Drought stress affected the infrared spectral region more than the visible spectral region. Reflectance sensitivity to water content of leaves was higher in the infrared spectral region than in the visible spectral region. Grasses irrigated at 100% and 80% of ET had no differences in normalized difference vegetation indices (NDVI), leaf area index (LAI), and stress indices. Grasses irrigated at 60% and 40% of ET had differences in NDVI, LAI, and stress indices. All measured wavelengths except 710nm were highly correlated (P < 0.0001) with turf visual quality, leaf firing, leaf rolling, soil moisture, chlorophyll content index, and photosynthesis. MSR could detect drought stress from the turf canopy.
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다중분광 위성자료와 분광반사 측정자료를 이용한 천수만 간석지 퇴적물 분류
장동호 ( Jang Dong Ho ),지광훈 ( Ji Gwang Hun ),이현영 ( Lee Hyeon Yeong ) 한국지형학회 2002 한국지형학회지 Vol.9 No.1
This study aimed to verify the grain-sized distribution of surface deposits in a tidal flat using multi-spectral satellite data as well as spectral reflectance In this study, Landsat TM acquired on September 1, 1996 was used. The results are as follows. First, the spectral reflectance is affected by the moisture content of deposits Likewise, reflectance consistently increases as the function ratio approaches zero percentage and decreases as the grain of deposits expands. Second, the grain-sired distribution analysis indicates that the mud flat inside the Cheonsu-bay tidal flat is distributed. the mixed flat located in the middle, and the rand flat distributed near the sea. Deposits mainly consist of periglacial deposits that were supplied from adjacent hills and reworked in the bottom of the sea. Third, the unsupervised classification ISODATA is applicable to classifying distribution material using satellite data. This method is considerably effective in analyzing not only the aspects of distribution in terms of accumulated deposits and erosion, but also the changes in seaside topography and shoreline. Therefore, the results suggest that multi-spectral satellite data enables the classification of distribution materials and environmental impact assessment and continuous monitoring. The research an environmental deposits in particular can provide important data for decision-making on seaside development. by analyzing the progress of deposits and environmental changes.
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ASTER 영상을 이용한 노화도 납석광상 지역 특성 연구
손영선,강문경,윤왕중 한국자원공학회 2011 한국자원공학회지 Vol.48 No.3
In this study, a multi-spectral ASTER image was analyzed to extract the spectral characteristics of hydrothermal alteration pyrophyllite deposit in Nohwa island. The band ratio and Principal Component Analysis (PCA) were used for this study. The Nohwa deposit showed strong absorption features in the ASTER band 5 (2.145~2.185 ㎛) and 6 (2.185~2.225 ㎛), which implies that the deposit is mainly composed of hydrothermal altered clay minerals containing Al-OH. The PCA using a covariance matrix was effective in compressing information content and removing noise. In addition, experiment showed that the PCA using four bands selected from the ASTER Visible Near Infrared Region (VNIR) and Short Wave Infrared Region (SWIR) bands is more useful than the band ratio to analyze the spectral characteristics of the pyrophyllite deposit in Nohwa island. 본 연구에서는 다중분광(multi-spectral) 원격탐사 영상 중 ASTER(Advanced Spaceborne Thermal Emission and Reflectance radiometer) 영상을 이용하여 노화도에 분포되어 있는 열수변질 납석광상 지역의 분광학적 특성을 분석하였다. 노화광상 지역의 분광학적 특성 분석을 위해 영상처리기법 중 밴드비율 기법과 주성분 분석 기법을 적용하였으며, 분석결과 노화광상은 ASTER 5번(2.145~2.185 ㎛)과 6번(2.185~2.225 ㎛) 밴드에 해당되는 분광대역에서 강한 흡수특성을 나타냈다. 따라서 이 지역은 주로 Al-OH 광물인 열수변질 점토광물들로 이루어진 지역으로 판단된다. 공분산 행렬식을 이용한 주성분 분석은 정보의 압축 및 잡음 제거에 효과적이었으며, 입력밴드를 ASTER 가시・근적외대역과 단파장 적외대역 밴드 9개 중 4개 밴드를 선택하여 주성분 변환을 수행한 결과, 밴드비율 기법에 비해 광상지역의 분광학적 특성을 보다 효과적으로 확인할 수 있었다.
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Sensor-based Technology for Assessing Drought Stress in Two Warm-Season Turfgrasses
Jae-Ho Hur(허재호),J. Bryan Unruh,Laurie E. Trenholm,Joon-Hee Lee(이준희) 한국잡초학회·한국잔디학회 2006 Weed & Turfgrass Science Vol.20 No.2
본 연구는 토양 수분함량을 즉시 파악할 수 있는 Time Domain Radiometer(TDR) 과 식물의 광합성 시 잎에서 반사되는 Reflectance를 통하여 식물의 상태를 파악할 수 있는 Multi-spectral radiometer(MSR)를 사용하여 난지형 잔디인 ‘Sea Isle 1' Seashore paspalum 과 ‘Floratam' St. Augustinegrass를 대상으로 토양수분함량과 Reflectance와의 상관관계를 파악하고자 시작하였다. 본 연구를 통해 토양 수분함량이 660, 694 wavelengths와 NDVI, LAI, stress index에서 높은 상관관계를 가지고 있음을 알 수 있었다. 이는 Sensor-based technology가 잔디의 수분요구 시점을 미리 파악할 수 있는 기술의 기초 자료로서 활용될 수 있으며 여러 다른 Sensor-based technology를 이용한 연구로 확대될 수 있을 것이다. This study was designed to determine what sensor based technologies might reliably and accurately predict irrigation scheduling needs of warm season turfgrass. ‘Floratam’ St. Augustinegrass[Stenotaphrum secundatum(Walt.) Kuntze] and ‘Sea Isle I’ seashore paspalum(Paspalum vaginatum Swartz) were established in tubs in the Envirotron Turfgrass Research Laboratory in Gainesville, FL in the spring of 2002. Each grass was subjected to repeated dry down cycles where irrigation was withheld. Sensor based data were collected and these evaluations were used to determine if irrigation scheduling could be determined based on plant response during dry down. Results indicated that reflectance indices(P≤ 0.001) and soil moisture(P≤ 0.0001) throughout the dry down cycle can predict the need for irrigation scheduling as turf quality declined below acceptable levels.
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