¬GPR mapping of cavity in complex scenarios with a combined time-depth conversion

The paper deals with a combined time-depth conversion strategy able to improve the reconstruction of voids embedded in an opaque medium, as cavities, caves, empty hypogeal rooms and similar targets. The combined time-depth conversion accounts for the propagation velocity of the electromagnetic waves both in free space and in the embedding medium and it allows a better imaging and interpretation of the underground scenario. To assess the strategy effectiveness, ground penetrating radar (GPR) data referred to an experimental test in controlled conditions are accounted for and processed by means of two different approaches to achieve focused images of the scenario under test. The first approach is based on a classical migration algorithm, while the second one faces the imaging as a linear inverse scattering approach. The results corroborate that the combined time-depth conversion improves the imaging in both cases.