Standoff gas detection, identification and quantification with a thermal hyperspectral imager

This paper presents detection and identification of gases using an infrared imaging Fourier-Transform Spectrometer (iFTS). The company Telops has developed an iFTS instrument, the Hyper-Cam, which is offered as a medium or long wave infrared sensor. The principle of operation of the spectrometer and the methodology for standoff gas detection and identification is shown in the paper. The algorithm for gas detection and identification is also shown. The gas detection and identification algorithm is generally based on three key factors: the composition of the analysed pixel, the type of model used to estimate the variability of the target and background spaces, and the model used to describe the pure and mixed pixels. The equation modelling the signal reaching the iFTS caused by the presence of a gas is presented and used with the reference signal obtained without the presence of a gas in iFTS’ field of view. Some results of the detection and identification of various types of gases are included in the paper