Results 271 to 280 of about 153,264 (305)
Some of the next articles are maybe not open access.
IEEE Signal Processing Magazine, 2014
Variable illumination and environmental, atmospheric, and temporal conditions cause the measured spectral signature for a material to vary within hyperspectral imagery. By ignoring these variations, errors are introduced and propagated throughout hyperspectral image analysis.
Alina Zare, K C Ho
exaly +2 more sources
Variable illumination and environmental, atmospheric, and temporal conditions cause the measured spectral signature for a material to vary within hyperspectral imagery. By ignoring these variations, errors are introduced and propagated throughout hyperspectral image analysis.
Alina Zare, K C Ho
exaly +2 more sources
Orthogonal Subspace Unmixing to Address Spectral Variability for Hyperspectral Image [PDF]
IEEE Transactions on Geoscience and Remote Sensing, 2023 International audienceHyperspectral unmixing aims at estimating pure spectral signatures and their proportions in each pixel. In practice, the atmospheric effects, intrinsic variation of the spectral signatures of the materials, illumination, and ...
Xu Sun, Longfei Ren, Danfeng Hong
exaly +2 more sources
Spectral variability of atlantic forest species
2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS, 2013This paper investigates the spectral variability of Brazilian Atlantic Forest trees. Spectroscopy data (reflectance and transmittance) of full sunlight leaves were collected. The root mean square difference between pairs of spectra were used to estimate within- and between-species variability.
Matheus Pinheiro Ferreira +3 more
openaire +1 more source
X-Ray Spectral Variability of 3C273
Space Science Reviews, 19853C273 has been monitored by EXOSAT over the period December 1983 to June 1984 in 4 observations. In the December observation the flux was high and the spectrum showed a power law index of 1.5 changing to 0.9 at~8 keV. In subsequent observations the flux dropped to~40% of its original value and the hard tail disappeared.
M.J.L. Turner +4 more
openaire +1 more source
Rapid Spectral Variability of DR Tau
Astrophysics and Space Science, 1998The Classical T Tauri stars (CTTS) are pre-main sequence stars surrounded by an accretion disk. Material from the disk is being accreted by the central object, probably by a strong magnetic field anchored to the star (Konigl 1991). The accreted material is channelled down the magnetic field lines and free falls onto the star’s surface, forming strong ...
K. W. Smith +4 more
openaire +1 more source
Spectral variability of blazars
AIP Conference Proceedings, 2000Broadband spectral characteristics of different subclasses of γ-ray blazars in different γ-ray intensity states are contrasted and discussed in the framework of currently popular leptonic jet models. Differences between quasars and BL-Lacs may be understood in terms of the dominance of different radiation mechanisms in the gamma-ray regime.
openaire +1 more source
Spectral Variability of Light-Emitting Diodes with Angle
Conference on Colour in Graphics, Imaging, and Vision, 2010Multispectral systems allow the spectral characterization of the scene through several acquisition channels with different spectral features. The spectral sampling can be done by using transmittance filters and a white light source or illuminating the scene using light sources with different spectral emission characteristics.
Martínez, Óscar +5 more
openaire +3 more sources
Spectral Analysis of Cardiovascular Variability Signals
1998It is well known that the control mechanisms of heart rate and blood pressure, as well as of many other cardiovascular parameters, manifest themselves though beat-to-beat variations in the related signals1,2. The quantification of these variations, both in control conditions and after provocative tests, plays a fundamental role for a better ...
CERUTTI, SERGIO +3 more
openaire +2 more sources
Astrophysics, 1994
In careful analysis of the CCD-spectra of P Cyg it was possible to identify 10 of the 43 lines that have been unidentified up to now. The majority of the latter belong to multiply ionized atoms. The conclusion is reached that there is anomalous heating in certain layers of the stellar wind.
G. L. Israelyan, A. G. Nikogosyan
openaire +1 more source
In careful analysis of the CCD-spectra of P Cyg it was possible to identify 10 of the 43 lines that have been unidentified up to now. The majority of the latter belong to multiply ionized atoms. The conclusion is reached that there is anomalous heating in certain layers of the stellar wind.
G. L. Israelyan, A. G. Nikogosyan
openaire +1 more source
Optical Spectral Variability of Blazars
Journal of Astrophysics and Astronomy, 2014It is well established that blazars show flux variations in the complete electromagnetic (EM) spectrum on all possible time scales ranging from a few tens of minutes to several years. Here, we report the review of optical flux and spectral variability properties of different classes of blazars on IDV and STV time-scales. Our analysis show HSPs are less
openaire +1 more source