Institution
Spectral Sciences Incorporated
Company•Burlington, Massachusetts, United States•
About: Spectral Sciences Incorporated is a company organization based out in Burlington, Massachusetts, United States. It is known for research contribution in the topics: Hyperspectral imaging & Radiance. The organization has 114 authors who have published 342 publications receiving 10875 citations.
Papers published on a yearly basis
Papers
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TL;DR: The results show that at high laser intensities (I>/=10(14) W/cm(2)) purely classical correlation is strong enough to account for all of the main features observed in experiments to date.
Abstract: We introduce a unified and simplified theory of atomic double ionization. Our results show that at high laser intensities ($I\ensuremath{\ge}{10}^{14}\text{ }\mathrm{W}/{\mathrm{c}\mathrm{m}}^{2}$) purely classical correlation is strong enough to account for all of the main features observed in experiments to date.
165 citations
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Ohio State University1, Space Telescope Science Institute2, Johns Hopkins University3, Georgia State University4, University of St Andrews5, Western Michigan University6, Tel Aviv University7, Valparaiso University8, University of California, Irvine9, Pennsylvania State University10, University College London11, University of Auckland12, University of Padua13, INAF14, Worcester State University15, Ohio University16, University of Maryland, College Park17, University of Leicester18, Goddard Space Flight Center19, Spectral Sciences Incorporated20, Morehead State University21, York University22, Leiden University23, Netherlands Institute for Space Research24, University of California, Santa Barbara25, University of Chile26, University of Southampton27, University of Crete28, Institution of Engineers, Sri Lanka29, University of California, Los Angeles30, University of Amsterdam31, University of Arizona32, University of Copenhagen33, University of Missouri34, Carnegie Mellon University35
TL;DR: In this paper, the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope are described.
Abstract: We describe the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Significant correlated variability is found in the continuum and broad emission lines, with amplitudes ranging from ∼30% to a factor of two in the emission lines and a factor of three in the continuum. The variations of all the strong emission lines lag behind those of the continuum, with He II λ1640 lagging behind the continuum by ∼2.5 days and Lyα λ1215 ,C IV λ1550, and Si IV λ1400 lagging by ∼5–6 days. The relationship between the continuum and emission lines is complex. In particular, during the second half of the campaign, all emission-line lags increased by a factor of 1.3–2 and differences appear in the detailed structure of the continuum and emissionline light curves. Velocity-resolved cross-correlation analysis shows coherent structure in lag versus line of sight velocity for the emission lines; the high-velocity wings of C IV respond to continuum variations more rapidly than the line core, probably indicating higher velocity broad-line region clouds at smaller distances from the central
158 citations
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21 Jul 2003TL;DR: A new spectra; recalibration algorithm, which has been incorporated intoFLAASH, is described and results from processing Hyperion data with FLAASH are discussed.
Abstract: A combination of good spatial and spectral resolution make visible to shortwave infrared spectral imaging from aircraft or spacecraft a highly valuable technology for remote sensing of the Earth's surface. Many applications require the elimination of atmospheric effects caused by molecular and particulate scattering; a process known as atmospheric correction, compensation, or removal. The Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) atmospheric correction code derives its physics-based algorithm from the MODTRAN4 radiative transfer code. A new spectra; recalibration algorithm, which has been incorporated into FLAASH, is described. Results from processing Hyperion data with FLAASH are discussed.
156 citations
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01 Jun 2005TL;DR: In this article, the spectral standard deviation of a collection of diverse material spectra, such as the end-member spectra in a scene, is essentially spectrally flat, allowing the retrieval of reasonably accurate reflectance spectra even when the sensor does not have a proper radiometric or wavelength calibration.
Abstract: We describe a new visible-near infrared short-wavelength infrared (VNIR-SWIR) atmospheric correction method for multi- and hyperspectral imagery, dubbed QUAC (QUick Atmospheric Correction) that also enables retrieval of the wavelength-dependent optical depth of the aerosol or haze and molecular absorbers. It determines the atmospheric compensation parameters directly from the information contained within the scene using the observed pixel spectra. The approach is based on the empirical finding that the spectral standard deviation of a collection of diverse material spectra, such as the endmember spectra in a scene, is essentially spectrally flat. It allows the retrieval of reasonably accurate reflectance spectra even when the sensor does not have a proper radiometric or wavelength calibration, or when the solar illumination intensity is unknown. The computational speed of the atmospheric correction method is significantly faster than for the first-principles methods, making it potentially suitable for real-time applications. The aerosol optical depth retrieval method, unlike most prior methods, does not require the presence of dark pixels. QUAC is applied to atmospherically correction several AVIRIS data sets and a Landsat-7 data set, as well as to simulated HyMap data for a wide variety of atmospheric conditions. Comparisons to the physics-based Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) code are also presented.
149 citations
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TL;DR: The U.S. Air Force's MODTRAN4 as mentioned in this paper is the latest version of the UAV spectral data collection system, which is used for analyzing spectral data for both atmospheric and surface characterization, and has been developed by the Air Force Research Laboratory / Space Vehicles Directorate (AFRL / VS) and Spectral Sciences, Inc.
Abstract: MODTRAN4, the newly released version of the U.S. Air Force atmospheric transmission, radiance and flux model is being developed jointly by the Air Force Research Laboratory / Space Vehicles Directorate (AFRL / VS) and Spectral Sciences, Inc. It is expected to provide the accuracy required for analyzing spectral data for both atmospheric and surface characterization. These two quantities are the subject of satellite and aircraft campaigns currently being developed and pursued by, for instance: NASA (Earth Observing System), NPOESS (National Polar Orbiting Environmental Satellite System), and the European Space Agency (GOME - Global Ozone Monitoring Experiment). Accuracy improvements in MODTRAN relate primarily to two major developments: (1) the multiple scattering algorithms have been made compatible with the spectroscopy by adopting a correlated-^ approach to describe the statistically expected transmittance properties for each spectral bin and atmospheric layer, and (2) radiative transfer calculations can be conducted with a Beer-Lambert formulation that improves the treatment of path inhomogeneities. Other code enhancements include the incorporation of solar azimuth dependence in the DISORT-based multiple scattering model, the introduction of surface BRDF (Bi-directional Radiance Distribution Functions) models and a 15 cm-1 band model for improved computational speed. Finally, recent changes to the HITRAN data base, relevant to the 0.94 and 1.13 um bands of water vapor, have been incorporated into the MODTRAN4 databases.
146 citations
Authors
Showing all 115 results
Name | H-index | Papers | Citations |
---|---|---|---|
Alexander Berk | 30 | 79 | 5554 |
N. Guler | 30 | 80 | 2482 |
Jonathan Gelbord | 29 | 87 | 3394 |
Lawrence S. Bernstein | 29 | 106 | 5106 |
Steven M. Adler-Golden | 29 | 98 | 4354 |
James Y-K. Cho | 24 | 42 | 2538 |
Prabhat K. Acharya | 21 | 36 | 3119 |
Michael W. Matthew | 20 | 31 | 2352 |
J. M. Gelbord | 15 | 33 | 1091 |
Jason Quenneville | 15 | 26 | 2176 |
Fritz Bien | 14 | 27 | 639 |
Xuemin Jin | 14 | 31 | 875 |
Neil Goldstein | 14 | 34 | 589 |
Jamine Lee | 13 | 27 | 1031 |
Rainer A. Dressler | 11 | 18 | 443 |