Backscattering on soil structure described by plane facets

In this paper, a new approach for soil roughness description is proposed. It is based on numerical three-dimensional soil surface images obtained by a stereoscopic device with a very fine resolution. The collected database contains four soils with different roughness (from smooth to ploughed). Each three-dimensional (3D) image is first approximated by juxtaposition of small plane facets. Statistics are then retrieved from sizes and slopes of facets in the segmented image. Analytical formulations are proposed for statistical laws showing a clear discrimination between the different soils of our database. In order to study numerically backscattering behaviour over soil, we generate profiles with respect to the retrieved statistics by applying Monte Carlo method. The Moment Method is used to compute the backscattered field over perfect conductor generated profiles. Finally, the results of numerical electromagnetic simulation are compared with the analytical Integral Equation Model (IEM) solution. Excellent agreement is obtained for soils belonging to the validity domain of IEM. For rougher soils, our model shows a realistic behaviour with incidence angle.

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