Self-Simulated Learning Artificial Intelligence for the Detection of
High Explosives in Soil by Mid Infrared Laser Spectroscopy
Abstract
A tunable mid-infrared (MIR) laser (quantum cascade laser, QCL) was used
for the detection of TNT and RDX in soil samples at a concentration
range from 0 to ~20% w/w. This type of sensing is
complicated due to the complexity of the matrix, i.e., the diversity of
compounds contained in soil. Thus, the high explosives (HE) detection in
soil by QCL was assisted with an Artificial Intelligence (AI) system. AI
managed to predict these HE in seven kinds of soils using minimum
information Machine Learning (ML). The models were generated only from
neat HE and soil spectra, without necessity using experimental spectra
of the mixes. AI used these neat spectra to simulate the spectra of
HEs/soil mixes. The simulated data was used to train the ML models and
then were tested with real spectra of HEs/soils mixes. The method was
designated as “Self-Simulated Learning Artificial Intelligence”
(SSLAI). This methodology has advantages for applications in field
scenarios where the matrices are unknown because SSLAI models do not
need to be trained with real samples a priori. Models would only have to
be fed with spectra for the neat components to train itself. The
methodology was tested with mixes of seven soils and two explosives.
Test samples were classified into three concentrations ranges: high
concentration test (Test_H > 10% w/w), medium
concentration test (10% w/w > Test_M > 3%
w/w), and low concentration test (Test_L < 3% w/w). The
results show that it is possible to correctly predict these two HE/soil
mixes from the simulated data. Specifically, for TNT and RDX, SSLAI
achieved a high precision in the prediction for the high and medium
concentration tests (Test_H and Test_M). However, for both samples
with concentrations below 3% w/w (Test_L), the number of false
positives increased, and the precision was reduced.