Point target behaviour in high resolution SAR images: time-frequency versus polarimetric analysis

Abstract:
The knowledge of backscattering nature involved in point target SAR responses is of prime interest for image understanding. Polarimetry is one apropriate method to get such information, although polarimetric images are not always available. With high resolution, backscattering is not necessarily stable over the entire integration time, which may provide additionnal information on target properties. Time-frequency analysis (TFA) enables to track such instability, both in azimuth and range. In this paper, we investigate two TFA methods (Wigner-Ville and “continuous sub-apertures”). TFA provides a sort of “radar spectrogram” at the pixel scale, i.e. scattering variations depending on the selected azimuth and range bandwidth. Finally the results are compared with real images polarimetric analysis outputs.