In this study, we investigated the assessment of the damaged area on composites ballistic plates subjected to high velocity impact. The active pulsed thermography technique was used for performing post-mortem analysis of the impacted specimens. Quantitative analysis of the damaged areas shows consistent results with the size of the projectile suggesting high precision of the quantification done in this work. This quantitative defect analysis combined with knowledge of projectile velocity allows for characterization of absorbed energy and differentiation of generated defect types. This allow for the evaluation of material efficiency in spreading absorbed energy over large areas. Our observations indicate that high velocity shots tend to induce smaller impact damage areas characterized primarily by fiber breakage, while low velocity shots tend to induce larger impact damage areas featuring predominantly delamination and matrix cracking damage mechanisms.
The integration of thermal infrared (TIR) hyperspectral systems into Unmanned Aerial Vehicles (UAVs) platforms is expected to open doors toward a wide variety of demanding thermal imaging applications ranging from academics and research to industry. Currently, the UAV remote sensing technology in TIR region is still in its infancy and the main expectations are the reduction of both, sensor sizes and cost while maintaining their performances at a high level.
In this communication, we report on Telops newly designed compact, light and robust TIR hyperspectral module of less than 10 kg with about 50W of power consumption. The new module can be integrated into a complete stand-alone imager with applications such as 360˚ Hyperspectral Surveillance. Integration in complete, highly flexible UAV based, infrared hyperspectral imaging solutions, such as airborne real-time gas detection, identification and quantification is also possible.
The need for a reliable and cost-efficient gas detection system is of prime importance especially when security threatening situations like gas leaks and emissions occur. The knowledge of the precise localization of the leaks, identification of the chemical nature of the gases involved and quantification of the gas flux emanating from the leaks are the crucial inputs needed for the incident response team to take actions based on relevant information. In this regard, UAVs based TIR remote sensing technology offers many benefits over traditional gas detection systems as it allows safely monitoring and imaging of large areas. The sensor can fly several hundreds of meters above the scene, avoiding the need to access restricted and potentially dangerous zones in the installations.
Beside the newly designed compact and light TIR hyperspectral module, Telops have also developed solutions for gas detection and identification along with some tools for the quantification of gas flow rates emanating for leak source. These solutions were recently demonstrated during a flight campaign up to 4600 feet above the ground for detection and identification of ethylene, methanol and acetone gas release experiment. The Fourier transform technology used in our hyperspectral imaging systems on an airborne platform allows recording of airborne hyperspectral data using mapping and targeting modes. These two acquisition modes were used for gas detection and real time quantitative airborne chemical images of the three gas clouds were obtained paving the path toward a viable solution for gas leak surveys and environmental monitoring.
The hyperspectral chemical mapping of open mines exploited by industries are among the possible applications that could possibly benefit from thermal infrared long-distance survey. More specifically the cement production essential in the constructions of our cities. The cement is made by mixing different raw materials and firing them in order to achieve precise chemical proportions of lime, silica, alumina and iron in the finished product. The quality of cement is therefore directly related to the chemistry of the raw materials used. Approximately 80 to 90% of the raw material is limestone. Clayey raw material accounts for between 10 to 15%, although precise amounts vary. Magnesium carbonate, which may be present in limestone, is the main undesirable impurity. The level of magnesia (MgO) should not exceed 5% and many producers prefer a maximum of 3%; this excludes dolomite or dolomitic limestones for the manufacture of cement.
In this work, we conducted thermal infrared (TIR) hyperspectral imaging for mineral mapping and mineralogy identification on a pit wall with Juracement at Cornaux using hyperspectral camera. This passive thermal infrared hyperspectral research instrument based on Fourier transform spectroscopy provides high spectral resolution data. The solid targets such as minerals not only emit but also reflect thermal infrared radiation. Since the two phenomena occur simultaneously, they end-up mixed in the radiance measured at the sensor level. To unveil the spectral features associated with minerals from TIR measurements, the respective contributions of self-emission and reflection in the measurement must be «unmixed» using temperature-emissivity separation (TES) algorithms. We developed a new TES procedure that allowed us to retrieve the spectral emissivity of the different minerals in the investigated scene. The chemical maps of the calcite dolomite mixtures were obtained on the pit wall the investigations were carried out, giving important insights on chemical the quality of the mine.
Gas leaks and air pollution sources present to a certain extend health, safety and environmental risks. A history of crisis management in the Upstream has shown the value of efficient and accurate tools for detecting gas leakages and/or the characterization air pollution agents. Knowing about the existence of a leak or the existence of an environmental thread is not always enough to launch a corrective action. Additional critical inputs such as the leak source, the chemical nature of the gas cloud, its direction and speed and as well as the gas concentration must most of the time be gathered in a short amount of time to help securing the hazardous areas. Most of the time gas identification for gas leaks surveys or environmental monitoring purposes involve explosives and/or toxic chemicals. In such situations, airborne measurements present particular advantages over ground based-techniques since large areas can be covered efficiently from a safe distance. In this work, we present our recent results on real time airborne gas detection up to 4600 feet above the ground using thermal hyperspectral Imaging technology. The Fourier transform technology used in the longwave (8-12 micron) hyperspectral camera on an airborne platform allows recording of airborne hyperspectral data using mapping and targeting modes. These two acquisition modes were used for gas imaging a ground-based ethylene, Methanol and acetone gas release experiment. Real time quantitative airborne chemical images of the three gas clouds were obtained paving the path toward a viable solution for gas leak surveys and environmental monitoring.
Heat transfers are involved in many phenomena such as friction, tensile stress, shear stress and material rupture. Among
the challenges encountered during the characterization of such thermal patterns is the need for both high spatial and
temporal resolution. Infrared imaging provides information about surface temperature that can be attributed to the stress
response of the material and breaking of chemical bounds. In order to illustrate this concept, tensile and shear tests were
carried out on steel, aluminum and carbon fiber composite materials and monitored using high-speed (Telops FASTM2K)
and high-definition (Telops HD-IR) infrared imaging. Results from split-Hopkinson experiments carried out on a
polymer material at high strain-rate are also presented. The results illustrate how high-speed and high-definition infrared
imaging in the midwave infrared (MWIR, 3 – 5 μm) spectral range can provide detailed information about the thermal
properties of materials undergoing mechanical testing.
Heat transfers are involved in many phenomena such as friction, tensile stress, shear stress and material rupture. Among the challenges encountered during the characterization of such thermal patterns is the need for both high spatial and temporal resolution. Infrared imaging provides information about surface temperature that can be attributed to the stress response of the material and breaking of chemical bounds. In order to illustrate this concept, tensile and shear tests were carried out on steel, aluminum and carbon fiber composite materials and monitored using high-speed (Telops FAST-M2K) and high-definition (Telops HD-IR) infrared imaging. Results from split-Hopkinson experiments carried out on a polymer material at high strain-rate are also presented. The results illustrate how high-speed and high-definition infrared imaging in the midwave infrared (MWIR, 3 – 5 μm) spectral range can provide detailed information about the thermal properties of materials undergoing mechanical testing.
The standard infrared camera has taken certain integration time with the photography per once, it was unsuitable for high-speed photography. By the infrared camera which can buffer photography data efficiently continually, high-speed photography of 2,000fps is enabled in 320X240 pixels and 11,000fps in128X100 pixels by windowing mode. The heat generation of specimen phenomenon is used for the monitoring of the start point of the destruction and the thermometry of combustion gases.
Optical fiber lasers offers the advantage of being relatively compact and efficient. However, the materials such as fluoride
and chalcogenide glasses used for their fabrication must be exempt of defects in order to make efficient laser systems.
However, most existing quality control techniques are not compatible with chalcogenide fibers because of their limited
transparency in the visible spectral range. For this reason, the Université Laval’s Centre d’optique, photonique et laser
(COPL), in Quebec City, Canada, has developed a novel non-destructive testing (NDT) methodology based on infrared
imaging to address this problem. The results show how this simple screening technique eases the selection of high-quality
fibers for the design of high-power mid-IR lasers.
Optical fiber lasers offers the advantage of being relatively compact and efficient. However, the materials such as fluoride and chalcogenide glasses used for their fabrication must be exempt of defects in order to make efficient laser systems. However, most existing quality control techniques are not compatible with chalcogenide fibers because of their limited transparency in the visible spectral range. For this reason, the Université Laval's Centre d'optique, photonique et laser (COPL), in Quebec City, Canada, has developed a novel non-destructive testing (NDT) methodology based on infrared imaging to address this problem. The results show how this simple screening technique eases the selection of high-quality fibers for the design of high-power mid-IR lasers.
Characterization of ship plumes is very challenging due to the great variety of ships, fuel, and fuel grades, as well as the extent of a gas plume. In this work, imaging of ship plumes from an operating ferry boat was carried out using standoff midwave (3-5 μm) infrared hyperspectral imaging. Quantitative chemical imaging of combustion gases was achieved by fitting a radiative transfer model. Combustion efficiency maps and mass flow rates are presented for carbon monoxide (CO) and carbon dioxide (CO2). The results illustrate how valuable information about the combustion process of a ship engine can be successfully obtained using passive hyperspectral remote sensing imaging.
Thermal infrared imaging is a field of science that evolves rapidly. Scientists have used for years the simplest tool: thermal
broadband cameras. These allow to perform target characterization in both the longwave (LWIR) and midwave (MWIR)
infrared spectral range. Infrared thermal imaging is used for a wide range of applications, especially in the combustion
domain. For example, it can be used to follow combustion reactions, in order to characterize the injection and the ignition
in a combustion chamber or even to observe gases produced by a flare or smokestack. Most combustion gases, such as
carbon dioxide (CO2), selectively absorb/emit infrared radiation at discrete energies, i.e. over a very narrow spectral range.
Therefore, temperatures derived from broadband imaging are not reliable without prior knowledge of spectral emissivity.
This information is not directly available from broadband images. However, spectral information is available using spectral
filters. In this work, combustion analysis was carried out using a Telops MS-IR MW camera, which allows multispectral
imaging at a high frame rate. A motorized filter wheel allowing synchronized acquisitions on eight (8) different channels
was used to provide time-resolved multispectral imaging of combustion products of a candle in which black powder has
been burnt to create a burst. It was then possible to estimate the temperature by modeling spectral profiles derived from
information obtained with the different spectral filters. Comparison with temperatures obtained using conventional
broadband imaging illustrates the benefits of time-resolved multispectral imaging for the characterization of combustion
processes.
Thermal infrared imaging is a field of science that evolves rapidly. Scientists have used for years the simplest tool: thermal broadband cameras. This allows to perform target characterization in both the longwave (LWIR) and midwave (MWIR) infrared spectral range. Infrared thermal imaging is used for a wide range of applications, especially in the combustion domain. For example, it can be used to follow combustion reactions, in order to characterize the injection and the ignition in a combustion chamber or even to observe gases produced by a flare or smokestack. Most combustion gases such as carbon dioxide (CO2) selectively absorb/emit infrared radiation at discrete energies, i.e. over a very narrow spectral range. Therefore, temperatures derived from broadband imaging are not reliable without prior knowledge about spectral emissivity. This information is not directly available from broadband images. However, spectral information is available using spectral filters. In this work, combustion analysis was carried out using Telops MS-IR MW camera which allows multispectral imaging at a high frame rate. A motorized filter wheel allowing synchronized acquisitions on eight (8) different channels was used to provide time-resolved multispectral imaging of combustion products of a candle in which black powder has been burnt to create a burst. It was then possible to estimate the temperature by modeling spectral profile derived from information obtained with the different spectral filters. Comparison with temperatures obtained using conventional broadband imaging illustrates the benefits of time-resolved multispectral imaging for the characterization of combustion processes.
For years, scientists have used thermal broadband cameras to perform target characterization in the longwave (LWIR)
and midwave (MWIR) infrared spectral bands. The analysis of broadband imaging sequences typically provides energy,
morphological and/or spatiotemporal information. However, there is very little information about the chemical nature of
the investigated targets when using such systems due to the lack of spectral content in the images. In order to improve
the outcomes of these studies, Telops has developed dynamic multispectral imaging systems which allow synchronized
acquisition on 8 channels, at a high frame rate, using a motorized filter wheel. An overview of the technology is
presented in this work as well as results from measurements of solvent vapors and minerals. Time-resolved multispectral
imaging carried out with the Telops system illustrates the benefits of spectral information obtained at a high frame rate
when facing situations involving dynamic events such as gas cloud dispersion. Comparison of the results obtained using
the information from the different acquisition channels with the corresponding broadband infrared images illustrates the
selectivity enabled by multispectral imaging for characterization of gas and solid targets.
For years, scientists have used thermal broadband cameras to perform target characterization in the longwave (LWIR)
and midwave (MWIR) infrared spectral bands. The analysis of broadband imaging sequences typically provides energy,
morphological and/or spatiotemporal information. However, there is very little information about the chemical nature of
the investigated targets when using such systems due to the lack of spectral content in the images. In order to improve
the outcomes of these studies, Telops has developed dynamic multispectral imaging systems which allow synchronized
acquisition on 8 channels, at a high frame rate, using a motorized filter wheel. An overview of the technology is
presented in this work as well as results from measurements of solvent vapors and minerals. Time-resolved multispectral
imaging carried out with the Telops system illustrates the benefits of spectral information obtained at a high frame rate
when facing situations involving dynamic events such as gas cloud dispersion. Comparison of the results obtained using
the information from the different acquisition channels with the corresponding broadband infrared images illustrates the
selectivity enabled by multispectral imaging for characterization of gas and solid targets.
For years, scientists have been using broadband cameras to perform measurements in the infrared spectral bands. In order to improve the outcomes of these studies, Telops has developed a fast multispectral imaging system in the LWIR and MWIR band.
This paper presents the improvement that a fast infrared multispectral imager adds to the traditional infrared investigations and how this system can be applied in defence innovation research. An overview over the technology is presented and discussed along the results obtained during a combustion experiment.
KEYWORDS: High dynamic range imaging, Cameras, Temperature metrology, Signal to noise ratio, Image quality, Calibration, Mid-IR, Nonuniformity corrections, Imaging systems, Infrared cameras
One of the biggest and challenging limitations of infrared cameras in surveillance applications is the limited dynamic range. Image blooming and other artifacts may hide important details in the scene when saturation occurs. Many different techniques such as using multiple exposure times have been developed in the past to help overcome these issues. However all these techniques feature non-negligible limitations. This paper presents a new high-dynamic range algorithm called Optimized Enhanced High Dynamic Range Imaging (OEHDRI). It is based on a pixel-wise exposure-time independent calibration as well as a pixel based frame summing with proper interleaved integration times. This technique benefits from the use of a high frame rate camera (< 20,000 fps). Description of the hardware is also included.
Image uniformity and accurate radiometric calibration are key features of state-of-the-art infrared cameras. Over the past years several non-uniformity correction and radiometric calibration techniques have been developed. In this paper we present and compare different techniques: 2-point calibration, CNUC™/multipoint’s calibration and Telops’ Real-Time Image Processing (patent-pending). For each method we assess the performances, the ease of use, the advantages and drawbacks as well as the most important operational limitations considering a broad range of exposure times, ambient and scene temperatures.
The level of protection offered by a given ballistic material is typically evaluated in terms of a set of projectiles and their associated velocity at which a certain percentage of the projectiles are expected to perforate. (i.e. FSP 17gr : V50 = 500m/s, 9mm FMJ; V0=500m/s). These metrics give little information about the physical phenomena by which energy is dispersed, spread or absorbed in a specific target material. Aside from post-test inspection of the impacted material, additional information on the target response is traditionally obtained during a test from the use of high speed imaging, whether it is from a single camera aimed at the impact surface or the backface, or from a set of camera allowing full 3-D reconstruction of a deformed surface. Again, this kind of data may be difficult to interpret if the interest is in the way energy is managed in the target in real time. Recent technological progress in scientific grade high-speed infrared (IR) camera demonstrated that these phenomena can straightforwardly be measured using IR thermal imaging. This paper presents promising results obtained from Telops FAST-IR 1500 infrared camera on an aramid-based ballistic composite during an impact from a small caliber fragment simulating projectile (FSP).
Dust cloud combustion is unfortunately at risk in many working environments, jeopardizing several workers. The heat and shock waves resulting from the flame propagation into the dust cloud are harmful and lead to major endangerment or casualties. More precisely, dust cloud (small particles) explosions are even more malicious since they often result from ordinary materials such as coal, flour or pollen. Also, many metal powdered (such as aluminum oxide and magnesium) can form dangerous dust cloud when they are in suspensions in air. The understanding of this particular type of combustion is critical for the preventive care of sites and workers afflicted to such conditions. This paper presents the results of a dynamic flow analysis of metal particles combustion in a dust cloud. The ignition points, the flow rate as well as the propagation direction of the flow have been characterized using fast infrared imagery.
Water ingress in honeycomb structures is of great concern for the civil and military aerospace industries. Pressure and
temperature variations during take-off and landing produce considerable stress on aircraft structures, promoting moisture
ingress (by diffusion through fibers or by direct ingress through voids, cracks or unsealed joints) into the core. The
presence of water (or other fluids such as kerosene, hydraulic fluid and de-icing agents) in any of its forms (gas vapor,
liquid or ice) promotes corrosion, cell breakage, and induce composite layer delaminations and skin disbonds. In this
study, testing specimens were produced from unserviceable parts from military aircraft. In order to simulate atmospheric
conditions during landing, selected core areas were filled with measured quantities of water and then frozen in a cold
chamber. The specimens were then removed from the chamber and monitored for over 20 minutes as they warm up
using a cooled high-resolution infrared camera. Results have shown that detection and quantification of water ingress on
honeycomb sandwich structures by passive infrared thermography is possible using a HD mid-wave infrared cameras for
volumes of water as low as 0.2 ml and from a distance as far as 20 m from the target.
Airborne hyperspectral ground mapping is being used in an ever-increasing extent for numerous
applications in the military, geology and environmental fields. The different regions of the
electromagnetic spectrum help produce information of differing nature. The visible, near-infrared and
short-wave infrared radiation (400 nm to 2.5 μm) has been mostly used to analyze reflected solar light,
while the mid-wave (3 to 5 μm) and long-wave (8 to 12 μm or thermal) infrared senses the self-emission
of molecules directly, enabling the acquisition of data during night time.
The Telops Hyper-Cam is a rugged and compact infrared hyperspectral imager based on the Fourier-transform
technology. It has been used on the ground in several field campaigns, including the
demonstration of standoff chemical agent detection. More recently, the Hyper-Cam has been integrated
into an airplane to provide airborne measurement capabilities. The technology offers fine spectral
resolution (up to 0.25 cm-1) and high accuracy radiometric calibration (better than 1 degree Celsius).
Furthermore, the spectral resolution, spatial resolution, swath width, integration time and sensitivity are
all flexible parameters that can be selected and optimized to best address the specific objectives of each
mission.
The system performance and a few measurements have been presented in previous publications. This
paper focuses on analyzing additional measurements in which detection of fertilizer and Freon gas has
been demonstrated.
Accurate radiometric calibration is a key feature of modern infrared cameras. Considering the newly available infrared
focal plane arrays (FPA) exhibiting very high spatial resolution and faster readout speed, we developed a method to
provide a dedicated radiometric calibration of every pixel. The novel approach is based on detected fluxes rather than
detected counts as is customarily done. This approach features many advantages including the explicit management of
the main parameter used to change the gain of the camera, namely the exposure time. The method not only handles the
variation of detector spectral responsivity across the FPA pixels but also provides an efficient way to correct for the
change of signal offset due to camera self-emission and detector dark current. The method is designed to require as few
parameters as possible to enable a real-time implementation for megapixel-FPAs and for data throughputs larger than
100 Mpixels/s. Preliminary results with a high-speed 3 μm to 5 μm infrared camera demonstrate that the method is
viable and yields small radiometric errors.
Hyperspectral ground mapping is being used in an ever-increasing extent for numerous applications in the military,
geology and environmental fields. The different regions of the electromagnetic spectrum help produce information of
differing nature. The visible, near-infrared and short-wave infrared radiation (400 nm to 2.5 μm) has been mostly used to
analyze reflected solar light, while the mid-wave (3 to 5 μm) and long-wave (8 to 12 μm or thermal) infrared senses the
self-emission of molecules directly, enabling the acquisition of data during night time.
Push-broom dispersive sensors have been typically used for airborne hyperspectral mapping. However, extending the
spectral range towards the mid-wave and long-wave infrared brings performance limitations due to the self emission of
the sensor itself. The Fourier-transform spectrometer technology has been extensively used in the infrared spectral range
due to its high transmittance as well as throughput and multiplex advantages, thereby reducing the sensor self-emission
problem.
Telops has developed the Hyper-Cam, a rugged and compact infrared hyperspectral imager. The Hyper-Cam is based on
the Fourier-transform technology yielding high spectral resolution and enabling high accuracy radiometric calibration. It
provides passive signature measurement capability, with up to 320x256 pixels at spectral resolutions of up to 0.25 cm-1.
The Hyper-Cam has been used on the ground in several field campaigns, including the demonstration of standoff
chemical agent detection. More recently, the Hyper-Cam has been integrated into an airplane to provide airborne
measurement capabilities. A special pointing module was designed to compensate for airplane attitude and forward
motion. To our knowledge, the Hyper-Cam is the first commercial airborne hyperspectral imaging sensor based on
Fourier-transform infrared technology. The first airborne measurements and some preliminary performance criteria for
the Hyper-Cam are presented in this paper.
Hyperspectral ground mapping is being used in an ever-increasing extent for numerous applications in the military,
geology and environmental fields. The different regions of the electromagnetic spectrum help produce information of
differing nature. The visible, near-infrared and short-wave infrared radiation (400 nm to 2.5 μm) has been mostly used to
analyze reflected solar light, while the mid-wave (3 to 5 μm) and long-wave (8 to 12 μm or thermal) infrared senses the
self-emission of molecules directly, enabling the acquisition of data during night time.
Push-broom dispersive sensors have been typically used for airborne hyperspectral mapping. However, extending the
spectral range towards the mid-wave and long-wave infrared brings performance limitations due to the self emission of
the sensor itself. The Fourier-transform spectrometer technology has been extensively used in the infrared spectral range
due to its high transmittance as well as throughput and multiplex advantages, thereby reducing the sensor self-emission
problem.
Telops has developed the Hyper-Cam, a rugged and compact infrared hyperspectral imager. The Hyper-Cam is based on
the Fourier-transform technology yielding high spectral resolution and enabling high accuracy radiometric calibration. It
provides passive signature measurement capability, with up to 320x256 pixels at spectral resolutions of up to 0.25 cm-1.
The Hyper-Cam has been used on the ground in several field campaigns, including the demonstration of standoff
chemical agent detection. More recently, the Hyper-Cam has been integrated into an airplane to provide airborne
measurement capabilities. A special pointing module was designed to compensate for airplane attitude and forward
motion. To our knowledge, the Hyper-Cam is the first commercial airborne hyperspectral imaging sensor based on
Fourier-transform infrared technology. The first airborne measurements and some preliminary performance criteria for
the Hyper-Cam are presented in this paper.
A cryogenic Fourier transform infrared spectrometer (Cryo-FTS) was developed for the Low Background Infrared
(LBIR) facility at the National Institute of Standards and Technology (NIST). This spectrometer was developed for the
Missile Defense Agency Transfer Radiometer (MDXR) that will be used to calibrate infrared sources that cannot be
transported to NIST for calibration. When used inside the MDXR, the Cryo-FTS provides relative spectral measurements
with a repeatability better than 1 % over the spectral range from 3 μm to 15 μm and at a spectral resolution of 0.6 cm-1.
This level of performance is enabled by the use of an advancec real-time resampling method.
The compact interferometer uses a compensated Michelson configuration and has an operating temperature range
between 10 K and 340 K with very low static beam redirection (< 215 μrad). The interferometer uses flat mirrors and a
KBr beamsplitter and compensator. This optics maintains low wavefront distortion for infrared beams of up to 2 cm
diameter and 5 mrad divergence. It integrates a digitally servo-controlled porchswing mechanism to provide an accurate
and repeatable optical path difference and is supported by a Wavefront Alignment (WA) system to correct for wavefront
residual tilt in real time using a fibre optic coupled metrology system. The interferometer provides modulation efficiency
of better than 44% with limited power dissipation (< 2.8 W) during operation.
Emerging applications in Defense and Security require sensors with state-of-the-art sensitivity and capabilities. Among
these sensors, the imaging spectrometer is an instrument yielding a large amount of rich information about the measured
scene. Standoff detection, identification and quantification of chemicals in the gaseous state is one important
application. Analysis of the surface emissivity as a means to classify ground properties and usage is another one.
Imaging spectrometers have unmatched capabilities to meet the requirements of these applications.
Telops has developed the FIRST, a LWIR hyperspectral imager. The FIRST is based on the Fourier Transform
technology yielding high spectral resolution and enabling high accuracy radiometric calibration. The FIRST, a man
portable sensor, provides datacubes of up to 320x256 pixels at 0.35mrad spatial resolution over the 8-12 μm spectral
range at spectral resolutions of up to 0.25cm-1. The FIRST has been used in several field campaigns, including the
demonstration of standoff chemical agent detection [http://dx.doi.org/10.1117/12.795119.1]. More recently, an airborne
system integrating the FIRST has been developed to provide airborne hyperspectral measurement capabilities. The
airborne system and its capabilities are presented in this paper.
The FIRST sensor modularity enables operation in various configurations such as tripod-mounted and airborne. In the
airborne configuration, the FIRST can be operated in push-broom mode, or in staring mode with image motion
compensation. This paper focuses on the airborne operation of the FIRST sensor.
A cryogenic Fourier transform infrared spectrometer (Cryo-FTS) was developed for the Low Background Infrared
(LBIR) facility at the National Institute of Standards and Technology (NIST). This spectrometer was developed for the
Missile Defense Agency Transfer Radiometer (MDXR) that will be used to calibrate infrared sources that cannot be
transported to NIST for calibration. When used inside the MDXR, the Cryo-FTS provides relative spectral measurements
with a repeatability better than 1 % over the spectral range from 3 μm to 15 μm and at a spectral resolution of 0.6 cm-1.
This level of performance is enabled by the use of an advancec real-time resampling method.
The compact interferometer uses a compensated Michelson configuration and has an operating temperature range
between 10 K and 340 K with very low static beam redirection (< 215 μrad). The interferometer uses flat mirrors and a
KBr beamsplitter and compensator. This optics maintains low wavefront distortion for infrared beams of up to 2 cm
diameter and 5 mrad divergence. It integrates a digitally servo-controlled porchswing mechanism to provide an accurate
and repeatable optical path difference and is supported by a Wavefront Alignment (WA) system to correct for wavefront
residual tilt in real time using a fibre optic coupled metrology system. The interferometer provides modulation efficiency
of better than 44% with limited power dissipation (< 2.8 W) during operation.
Emerging applications in Defense and Security require sensors with state-of-the-art sensitivity and capabilities. Among
these sensors, the imaging spectrometer is an instrument yielding a large amount of rich information about the measured
scene. Standoff detection, identification and quantification of chemicals in the gaseous state is one important
application. Analysis of the surface emissivity as a means to classify ground properties and usage is another one.
Imaging spectrometers have unmatched capabilities to meet the requirements of these applications.
Telops has developed the FIRST, a LWIR hyperspectral imager. The FIRST is based on the Fourier Transform
technology yielding high spectral resolution and enabling high accuracy radiometric calibration. The FIRST, a man
portable sensor, provides datacubes of up to 320×256 pixels at 0.35mrad spatial resolution over the 8-12 μm spectral
range at spectral resolutions of up to 0.25cm-1. The FIRST has been used in several field campaigns, including the
demonstration of standoff chemical agent detection [http://dx.doi.org/10.1117/12.788027.1]. More recently, an airborne
system integrating the FIRST has been developed to provide airborne hyperspectral measurement capabilities. The
airborne system and its capabilities are presented in this paper.
The FIRST sensor modularity enables operation in various configurations such as tripod-mounted and airborne. In the
airborne configuration, the FIRST can be operated in push-broom mode, or in staring mode with image motion
compensation. This paper focuses on the airborne operation of the FIRST sensor.
Emerging applications in Defense and Security require sensors with state-of-the-art sensitivity and capabilities. Among
these sensors, the imaging spectrometer is an instrument yielding a large amount of rich information about the measured
scene. Standoff detection, identification and quantification of chemicals in the gaseous state is one important
application. Analysis of the surface emissivity as a means to classify ground properties and usage is another one.
Imaging spectrometers have unmatched capabilities to meet the requirements of these applications.
Telops has developed the FIRST, a LWIR hyperspectral imager. The FIRST is based on the Fourier Transform
technology yielding high spectral resolution and enabling high accuracy radiometric calibration. The FIRST, a man
portable sensor, provides datacubes of up to 320×256 pixels at 0.35mrad spatial resolution over the 8-12 μm spectral
range at spectral resolutions of up to 0.25cm-1. The FIRST has been used in several field campaigns, including the
demonstration of standoff chemical agent detection. More recently, an airborne system integrating the FIRST has been
developed to provide airborne hyperspectral measurement capabilities. The airborne system and its capabilities are
presented in this paper.
The FIRST sensor modularity enables operation in various configurations such as tripod-mounted and airborne. In the
airborne configuration, the FIRST can be operated in push-broom mode, or in staring mode with image motion
compensation. This paper focuses on the airborne operation of the FIRST sensor.
A cryogenic Fourier transform infrared spectrometer (Cryo-FTS) was developed for the Low Background Infrared
(LBIR) facility at the National Institute of Standards and Technology (NIST). This spectrometer was developed for the
Missile Defense Agency Transfer Radiometer (MDXR) that will be used to calibrate infrared sources that can not be
transported to NIST for calibration. When used inside the MDXR, the Cryo-FTS is expected to be able to provide
relative spectral measurements with an accuracy of < 0.3 % uncertainty of infrared sources with a spectral range from 4μm to 15 μm and a spectral resolution of 0.6 cm-1.
The Cryo-FTS spectral range is determined by the beamsplitter since all of its other optics use reflective materials. The
compact interferometer uses a compensated Michelson configuration and has an operating temperature range between
10 K and 340 K with very low static beam redirection (< 215 μrad). The interferometer uses flat metal mirrors and KBr
flat optics and maintains low wavefront distortion for infrared beams of up to 1.63 cm diameter. It integrates a digitally
servo-controlled porchswing mechanism to provide an accurate and repeatable optical path difference and is supported
by a Wavefront Alignment (WA) system to correct for wavefront residual tilt in real time using a fibre optic based
metrology system. The interferometer is expected to provide modulation efficiency of better than 22% with limited
power dissipation (< 2.8 W) during continuous operation.
A cryogenic Fourier transform infrared spectrometer (Cryo-FTS) was developed for the Low Background Infrared
(LBIR) facility at the National Institute of Standards and Technology (NIST). This spectrometer was developed for the
Missile Defense Agency Transfer Radiometer (MDXR) that will be used to calibrate infrared sources that can not be
transported to NIST for calibration. When used inside the MDXR, the Cryo-FTS is expected to be able to provide
relative spectral measurements with an accuracy of < 0.3 % uncertainty of infrared sources with a spectral range from 4
μm to 15 μm and a spectral resolution of 0.6 cm-1.
The Cryo-FTS spectral range is determined by the beamsplitter since all of its other optics use reflective materials. The
compact interferometer uses a compensated Michelson configuration and has an operating temperature range between
10 K and 340 K with very low static beam redirection (< 215 μrad). The interferometer uses flat metal mirrors and KBr
flat optics and maintains low wavefront distortion for infrared beams of up to 1.63 cm diameter. It integrates a digitally
servo-controlled porchswing mechanism to provide an accurate and repeatable optical path difference and is supported
by a Wavefront Alignment (WA) system to correct for wavefront residual tilt in real time using a fibre optic based
metrology system. The interferometer is expected to provide modulation efficiency of better than 22% with limited
power dissipation (< 2.8 W) during continuous operation.
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