Gas characterization based on a snapshot interferometric imaging spectrometer
Résumé
Modern atmospheric gas monitoring applications demand progressively better performances with regards to spatial, spectral and temporal resolutions. In this context, great potential is shown by a newly developed family of cutting-edge snapshot imaging spectrometers based on Fabry-Perot interferometry, whose conceptual design was patented under the name ImSPOC. Three different sensor prototypes based on the ImSPOC concept are under development: 1) in the near infrared wavelength range for CH4 or H2S detection, 2) in ultraviolet and visible range for NO2 , O4 , O3 and O2 characterisation and 3) specifically for CO2 monitoring. After the realisation of these prototypes there is the need arose to provide intelligible and well-calibrated acquisitions for the final users. This study presents the ImSPOC concept from the signal processing point of view, framing the optical transformations performed in the instruments under an appropriate mathematical model formulation. Additionally, preliminary developments are presented to address the first step of the signal processing pipeline for this instrument: the estimation of the thickness of each interferometer. This is a fundamental step for obtaining calibrated acquisitions that could then be used for gas monitoring.