Hyperspectral quantitative imaging of gas sources in the mid-infrared Articles uri icon

publication date

  • January 2015

start page

  • 141

end page

  • 156

issue

  • 2

volume

  • 54

International Standard Serial Number (ISSN)

  • 1559-128X

Electronic International Standard Serial Number (EISSN)

  • 2155-3165

abstract

  • 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.

keywords

  • organic photovoltaic devices; thermotropic layers; solar control; light-absorption; collector