Ship and Oil-Spill Detection Using the Degree of Polarization in Linear and Hybrid/Compact Dual-Pol SAR

Monitoring and detection of ships and oil spills using synthetic aperture radar (SAR) have received a considerable attention over the past few years, notably due to the wide area coverage and day and night all-weather capabilities of SAR systems. Among different polarimetric SAR modes, dual-pol SAR data are widely used for monitoring large ocean and coastal areas. The degree of polarization (DoP) is a fundamental quantity characterizing a partially polarized electromagnetic field, with significantly less computational complexity, readily adaptable for on-board implementation, compared with other well-known polarimetric discriminators. The performance of the DoP is studied for joint ship and oil-spill detection under different polarizations in hybrid/compact and linear dual-pol SAR imagery. Experiments are performed on RADARSAT-2 C-band polarimetric data sets, over San Francisco Bay, and L -band NASA/JPL UAVSAR data, covering the Deepwater Horizon oil spill in the Gulf of Mexico.

I. Introduction

Maritime surveillance is of great environmental and economical interest, directly contributing to improve public safety and environmental protection. In particular, efficiently monitoring the ships, oil platforms and oil spills are of critical importance. Oil spills are highly damaging to the environment and pose serious threats to ecology and wildlife in the marine system. Oil pollution comes partly from frequent illegal ship discharges and partly from large ship and oil-rig accidents, namely the Prestige tanker disaster (in 2002, northwest coast of Spain) and, more recently, the British Petroleum (BP) Deepwater Horizon oil spill (in 2010, northern Gulf of Mexico).