Analysis of a thermal imaging method for landmine detection, using infrared heating of the sand surface

The experimental investigation was performed in a laboratory where a surrogate mine was buried at depths between 1 cm and 4 cm in dry sand, and sand which had initial water contents of 2.5%, 5% and 10%. The results show that an observable 'hot spot' develops on the sand surface above the mine, during the cooling phase of most tests. The water content of the sand was found to have a strong influence on the development of the hot spot. The surface temperature variation for dry sand tends to be less than that found for sands that contain water and the only test where the hot spot was not detected was in dry sand where the mine was buried at 4 cm. A one-dimensional finite difference model was used to describe the heat and mass transfer mechanisms and interpret the experimental results.