A Hybrid Qualitative-Quantitative Electromagnetic Imaging Method for Subsurface Prospecting

In the present paper, a hybrid electromagnetic imaging method for subsurface prospection is presented. The approach is based on the cascade of two blocks: a time-domain qualitative reconstruction algorithm followed by a multifrequency quantitative inverse-scattering technique. In the first phase, the scattered-field data estimated by adaptive filtering are exploited by a beamforming method to produce an initial image of buried targets. In the second phase, a multifrequency inexact-Newton inversion approach developed in Lebesgue spaces with variable exponents uses the first-step image in two different qualitative-quantitative combination strategies: as a priori information for setting the exponent function and to weight the solution updates inside the iterative inversion procedure. The approach has been validated using numerically simulated scattered-field data. An analysis on the effects of the application of the two qualitative-quantitative combination strategies is presented.