Kevin Gross

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$Research paper thumbnail of Estimating index of refraction, surface temperature, and downwelling radiance using polarimetric-hyperspectral imagery (P-HSI)$

Estimating index of refraction, surface temperature, and downwelling radiance using polarimetric-hyperspectral imagery (P-HSI)

2016 8th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS), 2016

A method for retrieving index of refraction from polarimetric hyperspectral imagery (P-HSI) has b... more A method for retrieving index of refraction from polarimetric hyperspectral imagery (P-HSI) has been developed using a model to describe the spectral variation of the index. Index of refraction is modeled in one of two ways to reduce the number of parameters in the problem. Additionally, MODTRAN is used to model the atmosphere, further reducing the number of variables and enabling an overdetermined solution to be found. Results from simulated data of a SiC target at 25°C, with realistic noise levels, show index is retrieved to within 0.0116 for the real component and 0.034 for the imaginary component. This also shows that the atmospheric downwelling can be accurately retrieved even without a priori knowledge.

Hyperspectral data exploitation: Progress from statistical methods toward machine learning

$Research paper thumbnail of Estimating Index of Refraction from Polarimetric Hyperspectral Imagery$

Estimating Index of Refraction from Polarimetric Hyperspectral Imagery

Current material identification techniques rely on estimating reflectivity or emissivity which va... more Current material identification techniques rely on estimating reflectivity or emissivity which vary with viewing angle. As off-nadir remote sensing platforms become increasingly prevalent, techniques robust to changing viewing geometries are desired. A technique leveraging polarimetric hyperspectral imaging (P-HSI), to estimate complex index of refraction,N (ν), an inherent material property, is presented. The imaginary component ofN (ν) is modeled using a small number of "knot" points and interpolation at in-between frequenciesν. The real component is derived via the Kramers-Kronig relationship. P-HSI measurements of blackbody radiation scattered off of a smooth quartz window show thatN (ν) can be retrieved to within 0.08 RMS error between 875 cm −1 ≤ν ≤ 1250 cm −1. P-HSI emission measurements of a heated smooth Pyrex beaker also enable successfulN (ν) estimates, which are also invariant to object temperature.

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Learning Set Representations for LWIR In-Scene Atmospheric Compensation

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

Atmospheric compensation of long-wave infrared (LWIR) hyperspectral imagery is investigated in th... more Atmospheric compensation of long-wave infrared (LWIR) hyperspectral imagery is investigated in this paper using set representations learned by a neural network. This approach relies on synthetic at-sensor radiance data derived from collected radiosondes and a diverse database of measured emissivity spectra sampled at a range of surface temperatures. The network loss function relies on LWIR radiative transfer equations to update model parameters. Atmospheric predictions are made on a set of diverse pixels extracted from the scene, without knowledge of blackbody pixels or pixel temperatures. The network architecture utilizes permutation-invariant layers to predict a set representation, similar to work performed in point cloud classification. When applied to collected hyperspectral image (HSI) data, this method shows comparable performance to Fast Line-of-Sight Atmospheric Analysis of Hypercubes-Infrared (FLAASH-IR), using an automated pixel selection approach. Additionally, inference time is significantly reduced compared to FLAASH-IR with predictions made on average in 0.24 s on a 128 pixel by 5000 pixel data cube using a mobile graphics card. This computational speed-up on a low-power platform results in an autonomous atmospheric compensation method effective for real-time, on-board use, while only requiring a diversity of materials in the scene.

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Hyperspectral analysis for standoff detection of dimethyl methylphosphonate on building materials

Building and Environment, 2016

High speed radiometric measurements of IED detonation fireballs

Proceedings of Spie the International Society For Optical Engineering, Apr 1, 2010

ABSTRACT Continuum emission is predominant in fireball spectral phenomena and in some demonstrate... more ABSTRACT Continuum emission is predominant in fireball spectral phenomena and in some demonstrated cases, fine detail in the temporal evolution of infrared spectral emissions can be used to estimate size and chemical composition of the device. Recent work indicates that a few narrow radiometric bands may reveal forensic information needed for the explosive discrimination and classification problem, representing an essential step in moving from &quot;laboratory&quot; measurements to a rugged, fieldable system. To explore phenomena not observable in previous experiments, a high speed (10mus resolution) radiometer with four channels spanning the infrared spectrum observed the detonation of nine home made explosive (HME) devices in the &lt; 100lb class. Radiometric measurements indicate that the detonation fireball is well approximated as a single temperature blackbody at early time (0 &lt; t

Phenomenological model for infrared emissions from high-explosive detonation fireballs

Prior to this work, a phenomenological description of mid-wave infrared (MWIR) emissions from hig... more Prior to this work, a phenomenological description of mid-wave infrared (MWIR) emissions from highexplosive (HE) detonation fireballs did not exist, hampering efforts to classify the type and size of HEs from their electro-optical signatures. In recent field tests, temporally-resolved infrared spectra (0.05 ≤ t ≤ 0.12 s, 2 ≤ ν ≤ 8 cm −1) were collected via a Fourier-transform spectrometer (FTS) from the detonation fireballs of two types of conventional military munitions (CMM) as well as uncased TNT and four types of enhanced novel explosives (ENEs). The FTS data is not appreciably corrupted by artifacts due to scene changes resulting from the fast transient events. The CMM spectra are dominated by continuum emission, and a single-temperature Planckian distribution, modified for atmospheric attenuation, captures most of the variation in the data. Fitted CMM temperatures are well described by an exponential decay to ambient at an approximate rate of 0.8 s −1. A two-temperature fit to CMM spectra improved results, suggesting variations in the temperature field are important. Some evidence of selective emission is identified by systematic patterns First, I am deeply indebted to my wife and three children for gracefully enduring this lengthy process and providing the needed support throughout. Without them, the stresses and difficulties encountered during this extended effort would have seemed much greater. Next, I extend my gratitude to Glen Perram who provided excellent guidance when needed and appropriate distance when lessons were better learned the hard way. From him I learned a variety of good things, many related to this work, others about broader aspects of science, and still others about life in general. Ronald Tuttle is to be thanked for both his academic advice and necessary support to see this project to its completion. The remaining committee members-Jim Engel, Stephen Cain, and Meir Pachter-also deserve recognition for their thoughtful contributions which improved the quality of this work. Thanks are extended to Greg Smith (technician) and Mark Houle (bureaucratic ninja) for their help in the planning, execution, and successful completion of several field tests. Of course friendships forged along the way made for a more enjoyable expericence: thanks (in no particular order) Bryan Steward,

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Detonation Discrimination Techniques using a FTIR system and a NIR CCD

ABSTRACT Bomb detonation flashes for three types of high explosives of 1, 10, and 100 lbs each we... more ABSTRACT Bomb detonation flashes for three types of high explosives of 1, 10, and 100 lbs each were recorded using a Bomem MR 154 Fourier Transform Infrared Spectrometer and a 316 x 252 30-Hz InGaAs array. The spectral signatures were recorded from 1.6 - 20 microns simultaneously using InSb and HgCdTe detectors with 245 ms temporal resolution. Novel key features have been identified that will aid in discriminating various types and sizes of flashes. Some of the features are spectral dependent projections of ones event&#39;s temporal data onto another event&#39;s temporal data, time dependence of the fireball size, ratios of specific integrated bands, and spectral dependence of temporal fit constants. Using Fisher discrimination and principal component techniques we project these features onto a line that maximizes the differences in the classes of flashes and then identify the Bayesian decision boundaries for classification.

Passive ranging using mid-wavelength infrared atmospheric attenuation

Enhanced material identification using polarimetric hyperspectral imaging

2014 Ieee Applied Imagery Pattern Recognition Workshop, Oct 1, 2014

Passive Ranging Using Infra-Red Atmospheric Attenuation

Proceedings of Spie the International Society For Optical Engineering, Mar 1, 2010

ABSTRACT Methods of estimating range to an emissive target based on the depth of an atmospheric a... more ABSTRACT Methods of estimating range to an emissive target based on the depth of an atmospheric absorption band are presented. The present work uses measurements of the CO2 absorption band centered at 2.0 mum where signal-to-background ratios are maximum for many applications. Observed spectra are compared to model spectra to estimate range. Spectral regions with minimal attenuation are used to estimate source parameters in order to isolate atmospheric transmission. The spectra of 21 high explosive events were used to test this technique. A simple technique treating the fireball as a blackbody consistently underestimated true range by approximately 13%. A more realistic source model using some order-of-magnitude assumptions of fireball composition reduces range error to 3%. The technique produces accurate results without requiring detailed knowledge of source parameters or atmospheric conditions.

<title>Mid-infrared imaging Fourier transform spectrometry for high power fiber laser irradiated fiberglass composites</title>

High Power Laser Materials Processing: Lasers, Beam Delivery, Diagnostics, and Applications, 2012

ABSTRACT New measurement techniques to study continuous wave (CW) laser-material interactions are... more ABSTRACT New measurement techniques to study continuous wave (CW) laser-material interactions are emerging with the ability to monitor the evolving, spatial distribution of the state of the surface-gas boundary layer. A qualitative analysis of gas phase combustion plumes above the surface of laser irradiated fiberglass composites is developed from fast framing hyperspectral imagery observations. An imaging Fourier Transform Spectrometer (IFTS) operating in the mid-infrared (MWIR) with high framing rate has recently been developed at the Air Force Institute of Technology (AFIT) in collaboration with Telops Inc. A 320 x 256 indium antimonide (InSb) focal plane array with spectral response from 1.5 - 5.5 μm is mated with a Michelson interferometer to achieve spectral resolutions as high as 0.25 cm-1. The very fast 16- tap InSb array frames at 1.9 kHz for the full 320 x 256 frame size. The single pixel field of view of 0.3 mrad provides a spatial resolution of 1 mm at the minimum focal distance of 3 m. Painted and unpainted fiberglass composites are irradiated with a 1064 nm CW Nd:YAG laser for 60 s at 100 W in air at atmospheric pressure. Selective emission in the region of 2100 - 3200 cm-1 is readily evident and is used to develop a time-dependent spatial map of both temperature and plume constituents. The time evolution of gas phase combustion products such as CO and CO2 molecules are monitored, with a spectral resolution of 2 cm-1. High-speed imagery is obtained using a low-pass filter for the interferograms, illustrating significant turbulent behavior during laser irradiation. Spatial brightness temperature maps exceed 600 K. Spatial variation in the ratio of [CO2]/[CO] indicates an interplay between heterogeneous and homogeneous kinetics.

Remote quantification of smokestack effluent mass flow rates using imaging Fourier transform spectrometry

Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XII, 2011

ABSTRACT A Telops Hyper-Cam midwave infrared (1.5 - 5.5mum) imaging Fourier-transform spectromete... more ABSTRACT A Telops Hyper-Cam midwave infrared (1.5 - 5.5mum) imaging Fourier-transform spectrometer (IFTS) was used to estimate industrial smokestack total effluent mass flow rates by combining spectrally-determined species concentrations with flow rates estimated via analysis of sequential images in the raw interferogram cube. Measurements of the coalburning smokestack were made with the IFTS at a stand-off distance of 350m. 185 hyperspectral datacubes were collected on a 128(W)×64(H) pixel sub-window (11.4×11.4cm2 per pixel) at a 0.5cm-1 spectral resolution. Strong emissions from H2O, CO2, CO, SO2, and NO were observed in the spectrum. A previously established single-layer radiative transfer model was used to estimate gas concentrations immediately above stack exit, and results compared reasonably with in situ measurements. A simple temporal cross-correlation analysis of sequential imagery enabled an estimation of the flow velocity at center stack. The estimated volumetric flow rate of 106+/-23m/s was within 4% of the reported value. Final effluent mass flow rates for CO2 and SO2 of 13.5+/-3.8kg/s and 71.3+/-19.3g/s were in good agreement with in situ rates of 11.6+/-0.1kg/s and 67.8+/-0.5g/s. NO was estimated at 16.1+/-4.2g/s, which did not compare well to the total NOx (NO +NO2) reported value of 11.2+/-0.2g/s. Unmonitored H2O, HCl , and CO were also estimated at 7.76+/-2.25kg/s, 7.40+/-2.00g/s, and 15.0+/-4.1 g/s respectively.

Nondestructive evaluation of aircraft coatings with infrared diffuse reflectance spectra

Thermosense: Thermal Infrared Applications XXXVII, 2015

<title>Understanding the influence of turbulence in imaging Fourier transform spectroscopy of smokestack plumes</title>

Algorithms and Technologies for Multispectral, Hyperspectral, and Ultraspectral Imagery XVII, 2011

A Telops Hyper-Cam Fourier-transform spectrometer (IFTS) was used to collect infrared hyper-spect... more A Telops Hyper-Cam Fourier-transform spectrometer (IFTS) was used to collect infrared hyper-spectral imagery of the smokestack plume from a coal-burning power facility to assess the influence of turbulence on spectral retrieval of temperature (T) and pollutant concentrations (Ci ). The mid-wave (1.5-5.5 mum) system features a 320x256 InSb focal-plane array with a 326 murad instantaneous field-of-view (IFOV). The line-of-sight distance

Flight test of an imaging O2(X-b) monocular passive ranging instrument

Proceedings of SPIE - The International Society for Optical Engineering

An instrument for monocular passive ranging based on atmospheric oxygen absorption near 762 nm ha... more An instrument for monocular passive ranging based on atmospheric oxygen absorption near 762 nm has been designed, built and deployed to track emissive targets. An intensified CCD array is coupled to variable band pass liquid crystal filter and 3.5 - 8.8 degree field of view optics. The system was first deployed for a ground test viewing a static jet engine in afterburner at ranges of 0.35 - 4.8 km, establishing a range error of 15%. The instrument was also flight tested in a C-12 imaging an the exhaust plume of another aircraft afterburner at ranges up to 11 km.

IFTS for Turbulent Flow Field Diagnostics

Imaging and Applied Optics, 2011

ABSTRACT Turbulent flow study could benefit from spatially-resolved spectra. We report a method f... more

IFTS for Harmonically Unsteady Combustion

Fourier Transform Spectroscopy and Hyperspectral Imaging and Sounding of the Environment, 2015

Mathematical model and experimental methodology for calibration of a LWIR polarimetric-hyperspectral imager

2014 IEEE Applied Imagery Pattern Recognition Workshop (AIPR), 2014

Hyper-Cam: Hyperspectral IR imaging applications in defence innovative research

2010 2nd Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing, 2010

... Yan Montembeault, Philippe Lagueux, Vincent Farley and André Villemaire Telops Inc., 100-2600... more

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