نتایج جستجو برای: spectral indices
تعداد نتایج: 243566 فیلتر نتایج به سال:
Crop residues on the soil surface protect the soil against erosion, increase water infiltration and reduce agrochemicals in runoff water. Crop residues and soils are spectrally different in the absorption features associated with cellulose and lignin. Our objectives were to: (1) assess the impact of water on the spectral indices for estimating crop residue cover (fR); (2) evaluate spectral wate...
A field experiment was carried out to assess biomass and nitrogen status inMediterranean pastures by means of hyperspectral high resolution field radiometric data. Spectral and agronomic measurements were collected at three different pasture growth stages and in grazed–ungrazed plots distributed over an area of 14 ha. Reflectance-based vegetation indices such as simple ratio indices (SR[i,j]) a...
Relative water content (RWC) in plants is one of the most important biochemical parameters and its deficiency limits efficiency of photosynthesis and crop productivity. The scientific reports on using spectroscopy in detecting drought stress for sesame plants are very rare. In this study, the possibility of identifying water stress in two sensitive (Naz-Takshakhe) and resistant (Yekta) genotype...
We report on the strengths of three spectral indicators-Mg(2), Hbeta, and Hn/Fe-in the integrated light of a sample of 100 field and cluster E/S0 galaxies. The measured indices are sensitive to age and/or metallicity variations within the galaxy sample. Using linear regression analysis for data with nonuniform errors, we determine the intrinsic scatter present among the spectral indices of our ...
Current methods for large-scale vegetation monitoring rely on multispectral remote sensing, which has serious limitation for the detection of vegetation stress. To contribute to the establishment of a generalized spectral approach for vegetation stress detection, this study compares the ability of high-spectral-resolution reflectance (R) and fluorescence (F) foliar measurements to detect vegeta...
Multispectral satellite images have been utilized in the National Agricultural Statistics Service (NASS) for crop cover classification and crop acreage estimation since the 1970's. Though ancillary data is utilized to enhance the classification accuracy, there are few applications that maximize the utilization of the feature information of the given multispectral images. Every multispectral ima...
Uncontrolled, large fires are a major threat to the biodiversity of protected heath landscapes. The severity of the fire is an important factor influencing vegetation recovery. We used airborne imaging spectroscopy data from the Airborne Prism Experiment (APEX) sensor to: (1) investigate which spectral regions and spectral indices perform best in discriminating burned from unburned areas; and (...
this research was done in order to submit a model for salinity map made with tm satellite data and salinity values in a buienzahra. the necessary processings such as principal component analysis and producing of different indices was done on the main bands. the 38 soil samples using random sampling (with 10×10 km dimension) from different horizons were designed and performed on the study area. ...
The objective of this work is to represent the information in the speech signal picked up by a throat microphone (TM) in an efficient manner in terms of number of bits required. Since the TM signal is unaffected by ambient noise, it is possible to extract the required information effectively under different environmental conditions. A spectral mapping technique is proposed from the TM speech to...
We present preliminary results from a systematic spectral study of pulsars and their wind nebulae using the Chandra X-Ray Observatory. The superb spatial resolution of Chandra allows us to differentiate the compact object’s spectrum from that of its surrounding nebulae. Specifically, for six Crab-like pulsars, we compare spectral fits of the averaged pulsar wind nebulae (PWN) emission to that o...
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