Research on Ground-Based LWIR Hyperspectral Imaging Remote Gas Detection.

Area of Science:

• Remote Sensing
• Spectroscopy
• Optical Engineering

Background:

• Advancements in ground-based long-wave infrared (LWIR) remote sensing are crucial for environmental monitoring.
• Hyperspectral imaging offers enhanced capabilities over traditional wide-band imaging for gas detection.

Purpose of the Study:

• To present new progress in ground-based LWIR remote sensing using windowing spatial and temporal modulation Fourier spectroscopy.
• To demonstrate the application of this technique for detecting 2D distribution of chemical gas volatile organic compounds (VOCs).

Main Methods:

• Utilized a Michelson interferometer with a corner-cube for spatial modulation and a cooled LWIR photovoltaic staring focal plane array (FPA) detector.
• Employed Fourier Transform (FT) processing, including data cube reorganization, correction, and apodization, to achieve LWIR hyperspectral imaging.
• Applied difference spectrum analysis to clearly visualize gas distribution in complex backgrounds and low concentrations.

Main Results:

• The CHIPED-1 LWIR hyperspectral imaging prototype achieved a noise equivalent spectral radiance (NESR) of 5.6 x 10⁻⁸ W · (cm⁻¹ · sr · cm²)⁻¹ at single sampling.
• Demonstrated clear spatial distribution of diethyl ether gas using difference spectrum analysis, overcoming challenges of low concentration and complex backgrounds.
• Confirmed the spectral response range of the prototype can reach 11.5 µm.

Conclusions:

• The developed spatial and temporal modulation Fourier spectroscopy technique offers significant advantages for LWIR hyperspectral imaging.
• This method proves effective for detecting and identifying organic gas VOCs, exhibiting high sensitivity and strong anti-interference capabilities.
• The technique shows potential for further improvement and broader applications in infrared detection.