S-EOS™, Photon etc.’s SWIR hyperspectral camera (FIGURE 1) is an ideal tool for rapid acquisition of spectrally resolved images. Contrary to conventional scanning technologies, Photon etc.’s hyperspectral camera covers the spectrum with a continuous acquisition of monochromatic full-frame images. As a consequence, it is possible to acquire from hundred thousands to millions of spectra in minutes. In addition to this, the collection time can be further decreased by limiting the acquisition to the spectral window of interest.
Effective and rapid detection of explosive liquid precursors is paramount for the identification of potential threats. In order to show the potential of S-EOS™ for the inspection of fabrics which may contain explosive liquid precursors, two drops of water and acetone were deposited on a sponge tissue (67x93 mm2) at two different positions. As shown in Figure 2(i), the presence of the two liquids was not visible to the naked eye.
The hyperspectral cube was acquired in 38 s for the complete spectral range (1000-2500 nm) with a 5 nm step and an exposition time of 80 ms.
The images at 1550 nm (figure 2(ii)) and 2100 nm (Figure 2(iii)) revealed the presence of the two precursors, and enabled the detection of an aqueous liquid (W), such as water, against an organic liquid (A), such as acetone.
The collected reflectance spectra were converted to absorbance spectra for comparison reasons.
In agreement with the literature, the spectra of the two zones confirmed the nature of the two liquids (Figure 3), with the typical absorbance bands of acetone and water.