Remote detection of polluted gases based on thermal infrared spectral imaging in the field

Abstract

This paper reports the new progress of long wave infrared remote sensing in the field, focusing on the implementation process of window scanning spatiotemporal modulation Fourier spectroscopic imaging technology. Utilizing the self-developed CHIPED-1 device, the spatial modulation interference was achieved through the use of a cone mirror Michelson interferometer. By combining it with a cooled long-wave infrared focal plane detector component and applying data processing steps such as acquisition, recombination, calibration, etc., high-spectral resolution imaging in long-wave infrared region was accomplished. The detection sensitivity index nesr (Noise Equivalent Spectral Radiance) of the self-developed CHIPED-1 long wave infrared hyperspectral imaging principle experimental device reaches 5.6 × 10⁻⁸w/(cm⁻¹.sr.cm²) in single pixel，Equivalent to commercial time modulation interferometric hyperspectral imagers; It reflects the progressiveness of the technology, and leaves much room for improvement.By testing the transmittance curve of polypropylene film, the spectral response range of CHIPED-1 infrared hyperspectral imaging principle experimental device reached 11.5 μm.The article also studied the hyperspectral imaging detection method for two-dimensional distributed chemical gas VOCs, taking the detection experiments of field high-rise buildings and ether gas as examples.Under complex backgrounds and low experimental concentrations, the presence of ether vapor cannot be observed from the infrared spectrum slices at the same wave number. However, after differential spectral processing, the spatial distribution of ether vapor can be clearly seen.The hyperspectral method is applied in the field of infrared detection of organic vapor VOCs, which has many advantages over wide-band thermal imaging methods, such as high sensitivity, strong anti-interference ability, and wide recognition range.