SPIE Journal Paper | 6 February 2025
KEYWORDS: Interferograms, Spectroscopy, Calibration, FT-IR spectroscopy, Tunable filters, Infrared spectroscopy, Optical engineering, Data processing, Equipment, Fourier transforms
The solar occultation flux Fourier transform infrared spectrometer boasts advantages such as high resolution, broadband analysis, non-contact measurement, fast response, flexibility, and visualization, making it an indispensable and important tool for monitoring unorganized emissions from vehicles in mobile monitoring systems. However, factors such as uneven road surfaces and fast cornering can cause sunlight to jitter, which not only leads to jitter in the interference signal detected by the infrared detector but also results in an expanded angle of incidence, causing spectral broadening and wavelength shift. These effects directly influence the line shape function of the instrument. To address this issue, we propose a method for correcting interferogram jitter. This method incorporates a Savitzky–Golay filter into the interferogram processing workflow to precisely determine the baseline of the interferogram. It then corrects the jitter caused by vehicle movement, environmental vibrations, and other factors, ensuring the baseline is zeroed out. Following this correction, the standard interferogram data processing (apodization, phase correction, etc.), the same spectral conversion workflow, and the gas concentration inversion method are applied. To verify the effectiveness of our method, we compared the results processed with the calibration algorithm to those without it. The experimental results demonstrate that our correction algorithm effectively eliminates interferogram jitter, enhances the spectral signal-to-noise ratio, increases the stability of the spectral baseline, and successfully retains more affected spectral data. This ensures consistency in the retrieval of atmospheric composition, providing robust support for the application of vehicle-mounted solar occultation flux Fourier transform spectrometer technology in mobile monitoring systems. It fully meets the demand for spectral data processing in such systems.
