Polarization signatures of man-made objects in the SW infrared spectral band

1998 ◽  
Author(s):  
Leslie S. Balfour ◽  
Yossi Bushlin ◽  
Nahum Brandman
Keyword(s):  
Spectral Band ◽  
Infrared Spectral

S.P.I.Rou.: a landscape synthesis tool in the infrared spectral band

1997 ◽  
Author(s):  
Karine Jaloustre-Audouin ◽  
Eric Savaria ◽  
Lucien Wald
Keyword(s):  
Spectral Band ◽  
Synthesis Tool ◽  
Infrared Spectral

scholarly journals Temperature Measurement Using Infrared Spectral Band Emissions From H2O

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Daniel J. Ellis ◽  
Vladimir P. Solovjov ◽  
Dale R. Tree
Keyword(s):  
Water Vapor ◽  
Optical Measurement ◽  
Spectral Band ◽  
Combustion Products ◽  
Infrared Emission ◽  
Optical Measurements ◽  
Reactor Wall ◽  
Gas Temperature ◽  
Infrared Spectral ◽  
Gas Measurement

Currently, there is no satisfactory method for measuring the temperature of the gas phase of combustion products within a solid fuel flame. The industry standard, a suction pyrometer or aspirated thermocouple, is intrusive, spatially and temporally averaging, and difficult to use. In this work, a new method utilizing the spectral emission from water vapor is investigated through modeling and experimental measurements. The method employs the collection of infrared emission from water vapor over discrete wavelength bands and then uses the ratio of those emissions to infer temperature. This method was demonstrated in the products of a 150 kWth natural gas flame along a 0.75 m line of sight, averaged over 1 min. Results from this optical method were compared to those obtained using a suction pyrometer. Data were obtained at three fuel air equivalence ratios that produced products at three temperatures. The optical measurement produced gas temperatures approximately 3–4% higher than the suction pyrometer. The uncertainty of the optical measurements is dependent on the gas temperature being ±9% at 850 K and 4% or less above 1200 K. Broadband background emission assumed to be emitted from the reactor wall was also seen by the optical measurement and had to be removed before an accurate temperature could be measured. This complicated the gas measurement but also provides the means whereby both gas and solid emission can be measured simultaneously.

GeTe4 channel waveguides for the mid-wave infrared spectral band

2014 ◽  
Author(s):  
Vinita Mittal ◽  
Lewis G. Carpenter ◽  
James C. Gates ◽  
James S. Wilkinson ◽  
Ganapathy Senthil Murugan
Keyword(s):  
Spectral Band ◽  
Infrared Spectral ◽  
Channel Waveguides

scholarly journals Standoff pump-probe photothermal detection of hazardous chemicals

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ramesh C. Sharma ◽  
Subodh Kumar ◽  
Abhishek Parmar ◽  
Mohit Mann ◽  
Satya Prakash ◽  
...  
Keyword(s):  
Homeland Security ◽  
Tuning Fork ◽  
Spectral Band ◽  
Quartz Tuning Fork ◽  
Detection Sensitivity ◽  
Hazardous Chemicals ◽  
Liquid Form ◽  
Pump Probe ◽  
Pump And Probe ◽  
Infrared Spectral

Abstract A novel pump-probe Photothermal methodology using Quartz Tuning Fork (QTF) detector has been demonstrated for the first time. A tunable mid-IR Quantum Cascade Laser (QCL) and a CW fixed wavelength visible laser have been used as the pump and probe beam respectively. The developed Photothermal (PT) technique is based on Quartz Tuning Fork (QTF) detector for the detection of hazardous/explosive molecules adsorbed on plastic surface and also in aerosols form. PT spectra of various trace molecules in the fingerprinting mid- infrared spectral band 7–9 µm from distance of 25 m have been recorded. The PT spectra of explosives RDX, TNT and Acetone have been recorded at very low quantities. Acetone is the precursor of explosive Tri-Acetone Tri-Phosphate (TATP). The experimentations using pump and probe lasers, exhibit detection sensitivity of less than 5 μg/cm2 for RDX, TNT powders and of ~ 200 nl quantity for Nitrobenzene (NB) and Acetone (in liquid form) adsorbed on surfaces, from a distance of ~ 25 m. The sensitivity of the same order achieved from a distance of 15 m by using only a mid-IR tunable pump laser coupled to QTF detector. Thus the pump-probe PT technique is more sensitive in comparison to single tunable QCL pump beam technique and it is better suited for standoff detection of hazardous chemicals for homeland security as well as for forensic applications.

Variation in understory and canopy reflectance during stand development in Finnish coniferous forests

2015 ◽  
Vol 45 (8) ◽  
pp. 1077-1085 ◽  
Author(s):  
Nea Kuusinen ◽  
Pauline Stenberg ◽  
Erkki Tomppo ◽  
Pierre Bernier ◽  
Frank Berninger
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Boreal Forests ◽  
Near Infrared ◽  
Spectral Band ◽  
Stand Development ◽  
Area Index ◽  
Spectral Bands ◽  
Site Fertility ◽  
Infrared Spectral

Inherent variability in the spectral properties of boreal forests complicates the retrieval of canopy properties such as canopy leaf area index from satellite images. Understanding the drivers of this variability could help provide better estimates of desired canopy cover properties. Field plot data from the Finnish National Forest Inventory and Landsat thematic mapper (TM) images were used to investigate the variation in canopy and understory reflectance during stand development in coniferous boreal forests. Spectral data for each plot were obtained from the Landsat pixel within which the plot center coordinates fell. Nonlinear unmixing was used to estimate the bidirectional reflectance factors (BRFs) of the “sunlit understory” and “canopy and shaded ground” components by site fertility and stand development classes. A forest albedo model was used to estimate the contribution of diffuse radiation reflected downwards from the canopy to the sunlit understory component. The sunlit understory BRF in the near-infrared spectral band decreased as the site fertility decreased and the forest matured, whereas the sunlit understory BRFs in the red and shortwave-infrared spectral bands concurrently increased. The BRFs of the canopy and shaded ground component decreased slightly during stand development, mostly in the near-infrared spectral band. Adding the diffuse contribution to the sunlit understory component changed the estimated component BRFs only a little (0.1%–1.7%) compared with those obtained using a linear mixing assumption. This effect was largest in the near-infrared spectral band and smallest in the red spectral band. For Norway spruce plots, the measured and estimated forest variables were well correlated with the BRFs in all of the studied spectral bands, but for the Scots pine plots, the correlations were notably weaker. Results show a greater importance of the fraction of visible sunlit understory on forest reflectance in Scots pine than in Norway spruce forests.

scholarly journals Three multispectral configurations of a snapshot kaleidoscope-based camera in long wavelength infrared spectral band

2020 ◽  
Vol 59 (26) ◽  
pp. 7779
Author(s):  
Adrien Mas ◽  
Guillaume Druart ◽  
Patrick Bouchon ◽  
Grégory Vincent ◽  
Sylvain Favier ◽  
...  
Keyword(s):  
Spectral Band ◽  
Long Wavelength ◽  
Infrared Spectral ◽  
Long Wavelength Infrared

scholarly journals Modeling radiative transfer in tropical rainforest canopies: sensitivity of simulated albedo to canopy architectural and optical parameters

2011 ◽  
Vol 83 (4) ◽  
pp. 1231-1242 ◽  
Author(s):  
Sílvia N. M. Yanagi ◽  
Marcos H. Costa
Keyword(s):  
Radiative Transfer ◽  
Near Infrared ◽  
Tropical Rainforest ◽  
Spectral Band ◽  
Canopy Structure ◽  
Optical Parameters ◽  
Strong Response ◽  
Spectral Bands ◽  
Infrared Spectral ◽  
Integrated Biosphere Simulator

This study evaluates the sensitivity of the surface albedo simulated by the Integrated Biosphere Simulator (IBIS) to a set of Amazonian tropical rainforest canopy architectural and optical parameters. The parameters tested in this study are the orientation and reflectance of the leaves of upper and lower canopies in the visible (VIS) and near-infrared (NIR) spectral bands. The results are evaluated against albedo measurements taken above the K34 site at the INPA (Instituto Nacional de Pesquisas da Amazônia) Cuieiras Biological Reserve. The sensitivity analysis indicates a strong response to the upper canopy leaves orientation (x up) and to the reflectivity in the near-infrared spectral band (rNIR,up), a smaller sensitivity to the reflectivity in the visible spectral band (rVIS,up) and no sensitivity at all to the lower canopy parameters, which is consistent with the canopy structure. The combination of parameters that minimized the Root Mean Square Error and mean relative error are Xup = 0.86, rVIS,up = 0.062 and rNIR,up = 0.275. The parameterizations performed resulted in successful simulations of tropical rainforest albedo by IBIS, indicating its potential to simulate the canopy radiative transfer for narrow spectral bands and permitting close comparison with remote sensing products.

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