The 3D semi-analytic mode matching (SAMM) algorithm is used to determine nearfield scattering from realistic targets buried in lossy, possibly rough soil where the source is a dipole placed within a borehole in the ground. SAMM has been successfully implemented as a forward model for inverse scattering algorithms, and can be used as a GPR design tool which is both cheaper and more efficient than experimentation. SAMM can be (and has been) used for geophysical, medical, and biological applications, including mine detection, pollution detection, microwave tumor detection. Other possible applications that could utilize SAMM are cell structure characterization, wall penetrating radar, and ultrasound sensing. In the SAMM algorithm, scattering is described by moderately low-order superpositions of spherical modes originating at user-specified coordinate scattering centers (CSCs), the mode coefficients are found numerically by leastsquares squares interfaces. SAMM succeeds best when scattering is described by relatively few modes: a new feature of the SAMM algorithm is that CSCs can possess orientation as well as location. With careful choices of the CSC axes, it is possible to describe scattering primarily with the radial mode families which allows 3D SAMM to become a quasi-2D algorithm with few (if any) azimuthal modes needed. Symmetries in each scattering portion of the problem may also be exploited separately, even if no symmetry exists in the total problem, which greatly reduces the number of modes needed.


Poster presented at the 2006 Thrust R1B Effective Forward Models Conference


Semi-Analytic Mode Matching, SAMM, borehole

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Algorithms, Three-dimensional imaging




Bernard M. Gordon Center for Subsurface Sensing and Imaging Systems (Gordon-CenSSIS)

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Bernard M. Gordon Center for Subsurface Sensing and Imaging Systems (Gordon-CenSSIS)

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