Ground penetrating radar tomography: algorithms and case studies

Algorithms based on two inversion procedures suggested in a previous study are applied to the problem of imaging and target detection using ground penetrating radar data acquired at two sites. One inversion procedure, referred to as the Fourier transform method, employs the spatial Fourier transform of measured data and requires subsurface inhomogeneities to be relatively deep. The second inversion method does not require the data to be Fourier transformed; however, it does require the additional restriction that inhomogeneities be relatively small. This is referred to as the far-field method. These two inversion relationships are used to reconstruct images of both spatial variations-in refractive index and log likelihood function. It is found that both procedures perform well at a site where only a single isolated inhomogeneity exists. At a second site, where there are two adjacent inhomogeneities, the Fourier transform method proved superior