Generation of bald Earth digital elevation models as applied to polarimetric SAR interferometry

In this paper we investigate the comparison of recently proposed schemes to retrieve the bald Earth elevation height of terrain under a vegetation layer, making use of interferometric, fully polarimetric radar remote sensing P-band data. These schemes base on the one hand on an interferometric optimization scheme, which is applied to maximize the separation of scattering phase centers related to the pertinent interferometric coherences, and on the other hand on a nonlinear line fit along these coherences in order to extrapolate the different interferometric phases to those phase values which relate to the bald earth elevation height. A χ²-test is performed on the data to estimate the validity of the line fitting in forested areas. Experimental results obtained from P-band fully polarimetric single baseline interferometric data acquired over the Amazon rain forest are used in order to compare the different interferometric bald Earth phases obtained from the proposed approaches. Results are compared against a single polarization channel experiment in HHHH-polarization mode under same experimental conditions to demonstrate the clear superiority of Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) over single polarization InSAR.