SHIP DETECTION USING POLARIMETRIC SAR IMAGES

Abstract

Polarimetric information is investigated for ship detection and characterization at operational satellite synthetic aperture radar (SAR) incidence angles (20°–60°). It is shown that among the conventional single-channel polarizations (HH, VV, or HV), HV provides the best ship–sea contrast at incidence angles smaller than 50°. Furthermore, HH polarization permits the best ship–sea contrast at near-grazing incidence angles. The wave polarization anisotropy is used for optimal information extraction from polarimetric SAR data. It is shown that fully polarimetric information permits a significant improvement in the ship–sea contrast for relatively calm wind conditions, in comparison with conventional (i.e., scalar) single-channel polarizations (i.e., HH, VV, or HV). For rougher sea conditions, the effectiveness of polarimetric tools may be significantly degraded. Ship characterization is also investigated using the symmetric scattering characterization method (SSCM). Identification of ship targets with significant symmetric scattering can provide a useful ship pitch angle estimate under certain conditions.