An imaging Fourier transform spectrometer operating in the medium infrared (1800-5000  cm(-1)) has been used to image two gas sources: a controlled CO2 leak at room temperature and the exhaust of a combustion engine. Spectra have been acquired at a resolution of 0.5  cm(-1) using an extended blackbody as the background. By fitting them with theoretical spectra generated with parameters from the High-Resolution Transmission Molecular Absorption database, quantitative maps of temperature and gas column density (concentration·path product) for the gas plumes have been obtained. Spectra are related to gas plume parameters by means of a radiometric model that takes into account not only gas absorption, but also its emission and the atmospheric absorption, as well as the instrument lineshape function. Measurements for the gas leak show very good agreement between retrieved and nominal values of temperature and CO2 column density. This result has direct application to obtain quantitative imaging of exhaust emissions from automobiles and other mobile sources, as shown here with measurements of exhaust gases in a diesel engine.

Accurate measurement of post-flame temperatures can significantly improve combustion efficiency and reduce harmful emissions, for example, during the development phase of new internal combustion engines and gas turbine combustors. Nonperturbing optical diagnostic techniques are capable of measuring temperatures in such environments but are often technically complex and validation is challenging, with correspondingly large uncertainties, often as large as 2 % to 5 % of temperature. This work aims to reduce these uncertainties by developing a portable flame temperature standard, calibrated via the Rayleigh scattering thermometry technique, traceable to ITS-90, with an uncertainty of 0.5 % of temperature (k = 1). By suitable burner selection and accurate gas flow control, a stable, square, flat flame with uniform post-flame species and temperature is realised. Following development, the standard flame is used to validate two IR emission spectroscopy systems, both measuring the line-integrated emission spectra in the post-flame region. The first utilises a Hyperspectral imaging FTIR spectrometer capable of measuring 2D species and temperature maps and the second, a high-precision single line-of-sight FTIR spectrometer. In the central post-flame region, the agreement between the Rayleigh and FTIR temperatures is within the combined measurement uncertainties and amounts to 1 % (k = 1) of temperature.

Gas detection can become a critical task in dangerous environments that involve hazardous or contaminant gases, and the use of imaging sensors provides an important tool for leakage location. This paper presents a new design for remote sensing of gas leaks based on infrared (IR) imaging techniques. The inspection system uses an uncooled microbolometer detector, operating over a wide spectral bandwidth, that features both low size and low power consumption. This equipment is boarded on a robotic platform, so that wide objects or areas can be scanned.The detection principle is based on the use of active imaging techniques, where the use of external IR illumination enhances the detection limit and allows the proposed system to operate in most cases independently from environmental conditions, unlike passive commercial approaches. To illustrate this concept, a fully radiometric description of the detection problem has been developed; CO 2 detection has been demonstrated; and simulations of typical gas detection scenarios have been performed, showing that typical industrial leaks of CH 4 are well within the detection limits.The mobile platform where the gas sensing system is going to be implemented is a robot called TurtleBot. The control of the mobile base and of the inspection device is integrated in ROS architecture. The exploration system is based on the technique of Simultaneous Localization and Mapping (SLAM) that makes it possible to locate the gas leak in the map.

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