Effect of Aspect Ratio of Landmine on Thermal Signatures in Landmine Detection

ABSTRACT

During the last decades, research in landmines detection received a growing interest in finding the reliable solutions for solving the problem of the detection and subsequent removal of mines. Now a day the mines are also made of plastic like materials and hence the conventional methods based on metal detector has its own limitation in locating such mines. Infrared thermography is one of the promising techniques that can be employed to detect the exact location of the mines buried under soil. The effectiveness of infrared thermography for landmine detection can be improved by theoretically modeling the thermal signatures generated in a diurnal cycle due to the variations of thermal properties of mine and the surrounding soil. Accurate prediction of thermal signature variation will assist in analyzing the thermal images obtained by thermography, so that the exact location of the mine can be determined. Thus heat and mass transfer analysis through soil in the presence of landmine is essential for prediction of mine using infrared imaging technique.

In the present work a mathematical model has been developed to simulate the heat and moisture variations in the soil in the presence of mine. The governing equations for energy and moisture conservation are developed using continuum principle. The resulting governing equations for simultaneous heat and moisture transfer are coupled and hence finite element method has been employed to solve the equations to obtain temperature and moisture variations as functions of space and time. The computational domain consists of a rectangular domain with the land mine located at the centre. Bi-linear quadratic isoparametric elements have been used to discretize the computational domain. As far as the boundary conditions are concerned all the sides of the landmine are assumed to be adiabatic for heat and moisture transfer, whereas convective boundary condition is assumed for the exposed top surface of the soil medium with the ambient. The variations of solar heat flux and ambient temperature in a diurnal cycle are taken into account in the computations. Simulation results are discussed for the effect of aspect ratio of the landmine on thermal signatures.

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