Case Studies: Ship-Sea contrast Optimization when using Polarimetric SARs

Source: R. Touzi, F. Charbonneau, R.K. Hawkings, K Murnaghan and X. Kavoun, presented at IGARSS, 2001, Australia

Summary of Paper:

Polarization information was investigated as to its ability to distinguish ships within sea clutter for the purposes of ship detection.

The results presented demonstrate the potential of the fully polarimetric data for enhancing ship detection. For comparison purposes, the single polarizations of HH, VV and HV were examined and compared to results from utilizing the fully polarimetric modes. The results are summarized in the table below. The key conclusion was the very promising use of polarization entropy and anistropy for ship detection at relatively calm wind conditions (7-14 knots). Their effectiveness are degraded at rougher sea conditions. At steep incidence angles and rougher sea state, the results are only slightly better than what can be achieved by HV.

Ship Detection	Polarization				Notes
	HH	HV/VH	VV	Quad-pol
Ship detection (ship/sea contrast)	shallow				Current RSAT-1 HH minimizes the sea state return providing good results for ship detection at wind speeds of 7-14 knots
		steeper			Cross pol provides the best contrast at steeper incidence angles; and effectiveness is not degraded in rougher sea conditions
					The ratio of HH-VV phase information provides better potential ship-sea discrimination than single channel
					Polarization derived parameters known as Entropy and Anisotropy are useful in enhancing ship-sea contrast. This provided the best discrimination, however rough sea conditions are limiting.