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This paper deals with the detection of a buried object beneath a rough surface in a two-dimensional configuration. A new method for detecting buried objects from wide-band, near-field, multi-static data is suggested. The so-called near-field configuration corresponds to a set of transmitters and receivers located along a line segment in the vicinity of the surface. The detection method proposed here is based on a correlation of the scattered fields from two sets of data associated with two transmitters. A theoretical study in the framework of a low-frequency approximation predicts an enhancement of the correlation peak resulting from cross-terms combining surface and target contributions, as confirmed by rigorous computations. The performance of the detector is tested with respect to both polarization and frequency through computation of the receiver operating characteristic curves. [ABSTRACT FROM AUTHOR]

Presents a study which examined the reconstructions from a measured scattering field of two dimensional (2D) dieelectric or conducting objects from multi-frequency experimental data. Theoretical background; Computational approach; Numerical results and discussion.

The method of decomposition of the time reversal operator has been introduced with the aim of focusing acoustic waves on a selected target. It is based on the derivation of the invariants of the time reversal operator, which is linked to the transfer matrix of the array of transducers insonifying a time invariant scattering medium. The theoretical and numerical results concern independent point-like scatterers. Here, we apply numerically the same technique to electromagnetic waves, and all the interactions between the various scatterers are taken into account. This method may be very useful to detect and localize buried objects. With this goal, we have investigated the role of polarization and of the geometrical or electromagnetic parameters, as well as the ability of accurately focusing on a scatterer. The sensitivity of the results to the initial set of data, namely the number of measurements or the accuracy, is also studied. [ABSTRACT FROM AUTHOR]

Provides technique for the numerical solution of 2-D electromagnetic scattering with 3-D sources. Factor of the electromagnetic interactions; Formulation of the homogenous domains; Computation of the linear equations.

The rigorous solution of the scattering by two-dimensional rough surfaces can be numerically performed thanks to the sparse matrix flat surface iterative approach (SMFSIA). However, this kind of computation still requires both large CPU time and memory. Consequently, a lot of work has been dedicated at extending the domain of validity of approximate methods beyond that of standard high and low frequency approximations. In this paper it is shown that SMSFIA can be simplified in order to get a fast approximate method, with low memory requirements. This approximation is valid for surfaces with small slopes, and coven the domain of validity of both the Kirchhoff -tangent plane approximation and the first-order small slope approximation. [ABSTRACT FROM AUTHOR]

Abstract: We present a rigorous model, based on a specific boundary integral formalism for the wave scattering from rough, one-dimensional, dielectric or conducting surfaces at low-grazing incidence and scattering angles. Even though this so-called Grazing Method of Moment is, from a numerical cost point of view, independent of the incidence, it remains very numerically demanding. We thus propose an extrapolation technique for faster monostatic diagram computation, based on the theoretical behavior of the scattering amplitude at low-grazing angles. This technique is compared to the GMoM and to some approximate models, for surfaces with Gaussian spectrum as well as for sea surface. [Copyright &y& Elsevier]