Ship detection and characterization using polarimetric SAR

Polarimetric information is investigated for ship detection and characterization at operational satellite SAR incidence angles (20◦ to 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 polarization anisotropy is often 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. RESUMÉ L’apport de l’information polarimétrique à la détection et la caractérisation des bateaux est étudiée. Parmi les polarisations conventionnelles HH, VV, et HV, la polarisation HV permet le meilleur contraste bateaumer aux angles d’incidence plus petits que 50◦. HH donne les meilleurs résultats aux incidences rasantes. L’anisotropie de polarisation a été utilisée pour l’extraction optimale de l’information polarimétrique. La polarimétrie permet une grande amélioration du contraste bateau-mer dans des conditions de mer et vents relativement calmes. L’efficacité de la polarimétrie est réduite quand la mer est agitée. La méthode SSCM a été testée pour la caractérisation de bateaux. Elle a même permis une mesure de l’angle de tangage de bateaux dans certaines conditions. under contract with TGIS Consultant currently seconded to Defence R&D Canada Ottawa CAN. JOUR. OF REM. SENS., RADARSAT-2 SPECIAL ISSUE, JUNE 2004 2 LIST OF FIGURES AND TABLES • Figure 1: Artic Pride (AP) Vessel • Figure 2: Anne S Pierce (ASP) Vessel • Figure 3: Ship-sea contrast as a function of SAR incidence angle • Figure 4: Convair-580 SAR image at the HH polarization • Figure 5: Polarization Anisotropy Image • Figure 6: Target Poincaré sphere • Table 1: AP main feature’s Poincaré sphere coordinates • Table 2: ASP main feature’s Poincaré sphere coordinates CAN. JOUR. OF REM. SENS., RADARSAT-2 SPECIAL ISSUE, JUNE 2004 3