There are many types of natural gas fields including shale formations which are common especially in the St-Lawrence Valley (Canada). Since methane (CH 4 ), the major component of shale gas, is odorless, colorless and highly flammable, in addition of being a greenhouse gas, methane emanations and/or leaks are important to consider for both safety and environmental reasons. On this regard, passive remote sensing represents an interesting approach since it allows characterization of large areas from a safe location. In order to illustrate the potential of passive thermal infrared hyperspectral imaging for research on natural gas, imaging was carried out on a shale gas leak that unexpectedly happened during a geological survey near Hospital Enfant-Jesus (Québec City, Canada) in December 2014. Quantitative methane imaging was carried out based on its unique infrared spectral signature. The results show how this novel technique could be used for advanced research on shale gases.

Efforts are continuously made to improve internal combustion engines’ (ICEs) efficiency. Lowering fuel consumption and reducing soot formation are among the challenges being addressed when seeking to improve engine designs. In this work, ICE characterization was carried out on an optical engine at Istituto Motori Consiglio Nazionale delle Ricerche (CNR), in Napoli, Italia. The setup consists of an elongated single-cylinder diesel engine equipped with the multi-cylinder head of a conventional car and a common rail injection system. In this system, the piston’s crown is replaced by a sapphire window in order to carry out imaging of the combustion bowl. Imaging is achieved while the engine is in operation by looking at a 45° fixed mirror located in the extended piston axis. Infrared imaging was carried out at 26 kHz, leading to a temporal resolution of about 0.35° crankshaft angle at 1500 RPM. In the experiment, air was replaced by a premixed air-methane charge in order to improve combustion and lower the amount of soot deposits. The different phases of a combustion cycle, i.e. intake, compression, fuel injection, working stroke and exhaust, were investigated using four different spectral filters (broadband, CO2 red-spike, through-flame, hydrocarbon and methane). The results illustrate how high-speed IR imaging can provide unique insights for research on ICEs.

There are many types of natural gas fields including shale formations that are common especially in the St-Lawrence Valley (Canada). Since methane (CH4), the major component of shale gas, is odorless, colorless and highly flammable, in addition to being a greenhouse gas, methane emanations and/or leaks are important to consider for both safety and environmental reasons. Telops recently launched on the market the Hyper-Cam Methane, a field-deployable thermal infrared hyperspectral camera specially tuned for detecting methane infrared spectral features under ambient conditions and over large distances. In order to illustrate the benefits of this novel research instrument for natural gas imaging, the instrument was brought on a site where shale gas leaks unexpectedly happened during a geological survey near the Enfant-Jesus hospital in Quebec City, Canada, during December 2014. Quantitative methane imaging was carried out based on methane’s unique infrared spectral signature. Optical flow analysis was also carried out on the data to estimate the methane mass flow rate. The results show how this novel technique could be used for advanced research on shale gases.

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 mu m) 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.

Characterization of turbulent flames typically requires high temporal and spatial resolution on a wide field-of-view in order to cope for the unpredictable behaviour of these systems.Infrared imaging first appears to be a well-suited diagnostic tool for combustion reactions.However, it is well known that many common combustion gases such as water vapour (H2O) and carbon dioxide (CO2) selectively absorb and emit infrared radiation over a very narrow spectral range.Therefore, information about spectral emissivity using infrared imaging is required in order to obtain quantitative results.Using infrared imaging in combination with band-pass filters provides spectral information and has already been used for characterizing different stages of combustion experiments [1-3].However, if only one spectral filter is used at a time, it limits the use of this technique to steady-state (e.g.laminar flames) systems [1] and/or cyclic phenomena [2,3].Recording spectral information at high temporal resolution is then required in order to achieve characterization of unsteady combustion phenomenon like turbulent flames.In this work, ignition and steady-state combustion of hot methanol vapours were investigated using high-speed midwave infrared (MWIR, 3-5.5 µm) multispectral imaging.The camera was equipped with an 8-position fast-rotating filter wheel.The infrared filter selection included bandpass filters associated with CO2, H2O, carbon monoxide (CO) and hydrocarbons (HCs) infrared self-emission spectral ranges.A neutral density filter was also used in order to get a broadband image of the scene.Image acquisition was carried out at 800 Hz in a fully synchronized mode with the filter wheel rotating at 6000 revolutions per minute.This lead to an effective frame rate of 100 Hz per spectral band allowing detailed observation of turbulences while gathering spectral information at the same time.In the experiment, a flame was placed right above, but not in contact with, a recipient containing hot methanol.Once the flame reached the area where methanol vapours were in sufficient concentration, the flame propagated and ignited the reservoir.Significant amounts of unburnt methanol vapours could be detected above the reservoir in the instant following the burst caused by the ignition.In-band radiance profiles (IBR) were obtained by combining the results of the different spectral bands.A simple radiative transfer model was developed according to the phenomenology of methanol combustion.Temperature and gas column density estimates were obtained through the simulation of IBR profiles.Flame temperatures on the order of 900 K were estimated by using spectral information.These results are significantly higher than the 400 -500 K values measured by broadband infrared imaging.The results illustrate the potential of high-speed multispectral imaging as a quantitative diagnostic tool for characterizing turbulent flames.

Characterization of hazardous lands using ground-based techniques can be very challenging. For this reason, airborne surveys are often preferred. The use of thermal infrared imaging represents an interesting approach as surveys can be carried out under various illumination conditions and that the presence of buried objects typically modifies the thermal inertia of their surroundings. In addition, the burial or presence of a buried object will modify the particle size, texture, moisture and mineral content of a small region around it. All these parameters may lead to emissivity contrasts which will make thermal contrast interpretation very challenging. In order to illustrate the potential of airborne thermal infrared hyperspectral imaging for buried object characterization, various metallic objects were buried in a test site prior to an airborne survey. Airborne hyperspectral images were recorded using the targeting acquisition mode, a unique feature of the Telops Hyper-Cam Airborne system which allows recording of successive maps of the same ground area. Temperatureemissivity separation (TES) was carried out on the hyperspectral map obtained upon scene averaging. The thermodynamic temperature map estimated after TES highlights the presence of hot spots within the investigated area. Mineral mapping was carried out upon linear unmixing of the spectral emissivity datacube obtained after TES. The results show how the combination of thermal information and mineral distribution leads to a better characterization of test sites containing buried objects.

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.

Processing long-wave infrared (LWIR) hyperspectral imagery to surface spectral emissivity or reflectance units via atmospheric compensation and temperature-emissivity separation (TES) affords the opportunity to remotely classify and identify surface materials with minimal interference from atmospheric effects. This paper describes an automated atmospheric compensation and TES method, called FLAASH-IR (Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes Infrared), and its application to airborne imagery taken with the Telops Inc. Hyper-Cam interferometric hyperspectral imager. The results demonstrate good suppression of the atmospheric features due to water vapor and ozone, resulting in quantitative surface spectra, even with highly reflective (low emissivity) objects such as bare metal.

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.

Characterization of gas clouds are challenging situations to address due to the uneven distribution of these large entities as a function of time. Whether gas characterization is carried out for gas leaks surveys or environmental monitoring purposes, explosives and/or toxic chemicals are often involved. In such situations, airborne measurements present distinct advantages over ground based-technics since large areas can be covered efficiently from a safe distance. Most gases are infrared-active and can be probed using infrared imaging. Airborne thermal infrared hyperspectral imaging was carried out above smokestacks and a ground-based gas release experiment in order to illustrate the benefits of this technique to characterize gas clouds. Quantitative airborne chemical images of carbon monoxide (CO) and ethylene (C 2 H 4 ) were obtained from measurements carried out using a midwave (3-5 μm) and a longwave (8-12 μm) airborne infrared hyperspectral sensor respectively. Airborne measurements were carried out using both mapping and targeting acquisition modes. The later provides unique time-dependent information such as the gas cloud direction and velocity.

Characterization of gas clouds are challenging situations to address due to the large and uneven distribution of these fast moving entities. Whether gas characterization is carried out for gas leaks surveys or environmental monitoring purposes, explosives and/or toxic chemicals are often involved. In such situations, airborne measurements present distinct advantages over ground based-techniques since large areas can be covered efficiently from a safe distance. In order to illustrate the potential of airborne thermal infrared hyperspectral imaging for gas cloud characterization, measurements were carried out above smokestacks and a ground-based gas release experiment. Quantitative airborne chemical images of carbon monoxide (CO) and ethylene (C2H4) were obtained from measurements carried out using a midwave (MWIR, 3-5 mu m ) and a longwave (LWIR, 8-12 mu m) airborne infrared hyperspectral sensor respectively. Scattering effects were observed in the MWIR experiments on smokestacks as a result of water condensation upon rapid cool down of the hot emission gases. Airborne measurements were carried out using both mapping and targeting acquisition modes. The later provides unique time-dependent information such as the gas cloud direction and velocity.

Processing long-wave infrared (LWIR) hyperspectral imagery to surface emissivity or reflectance units via atmospheric compensation and temperature-emissivity separation (TES) affords the opportunity to remotely classify and identify solid materials with minimal interference from atmospheric effects. This paper describes an automated atmospheric compensation and TES method, called FLAASH®-IR (Fast Line-of-sight Atmospheric Analysis of Spectral Hypecubes-- Infrared), and its application to ground-to-ground imagery taken with the Telops Inc. Hyper-Cam interferometric hyperspectral imager. The results demonstrate that clean, quantitative surface spectra can be obtained, even with highly reflective (low emissivity) objects such as bare metal and in the presence of some illumination from the surroundings. In particular, the atmospheric compensation process suppresses the spectral features due to atmospheric water vapor and ozone, which are especially prominent in reflected sky radiance.

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.

Airborne thermal infrared (TIR) imaging is often used to study the problematic of urban heat islands (UHI). However, surface temperature measurement using remote sensing techniques often fail to take into account the spectral emissivity of the investigated materials. This leads to mismatches between the true surface temperature and the measured brightness temperature obtained from conventional broadband TIR sensors. Airborne TIR hyperspectral imaging (HSI) was carried out on urban and rural areas at high spectral resolution. The thermodynamic temperature maps obtained upon temperature-emissivity separation (TES) display sharper thermal contrast associated with UHI than their corresponding brightness temperature maps A chemical map of quartz could also be obtained from the emissivity datacubes. The results illustrate the potential of TIR HSI to address the UHI problematic.

This paper presents detection and identification of gases using an infrared imaging Fourier-Transform Spectrometer (iFTS).The company Telops has developed an iFTS instrument, the Hyper-Cam, which is offered as a medium or long wave infrared sensor.The principle of operation of the spectrometer and the methodology for standoff gas detection and identification is shown in the paper.The algorithm for gas detection and identification is also shown.The gas detection and identification algorithm is generally based on three key factors: the composition of the analysed pixel, the type of model used to estimate the variability of the target and background spaces, and the model used to describe the pure and mixed pixels.The equation modelling the signal reaching the iFTS caused by the presence of a gas is presented and used with the reference signal obtained without the presence of a gas in iFTS' field of view.Some results of the detection and identification of various types of gases are included in the paper along with quantification of detected gases.