Microwave Scattering Profiles of a Rice Sample by Means of Polarization Coherence Tomography

In this work we have applied the polarization coherence tomography (PCT) to indoor data acquired on a rice sample. Different baselines, frequency bands and polarimetric channels have been used in order to analyze the potential of this technique for retrieving information about the vertical structure of such a specific crop and, additionally, these observations have been also used for studying the validity of the RVoG and OVoG models. Results obtained show that the PCT profiles exhibit no dependence on polarization, which is in agreement with the clustering effect observed on PolInSAR observables, i.e. coherences for different polarimetric channels are located very close one to another. In the dual-baseline case, the best profile reconstruction is obtained for the highest baseline ratio available (0.25deg and 1deg baselines) when the condition number of the inversion problem is improved by filtering out the fifth coefficient of the Legendre-Fourier expansion. Differences on the reconstructed profiles between linear and Pauli basis are negligible. The application of the triple-and four-baseline approaches without filtering out the last terms of the expansion leads to unstable results, whereas the filtered cases reveal that the contribution of a fourth baseline is null.