A Detailed Comparison between Radar and Optical Vessel Signatures

A comparison is made between vessel signatures in four RADARSAT Fine images (8 m resolution) and four high resolution optical images (Panchromatic SPOT 5 m, 2.5 m and EROS 1.9 m). Thirty vessels are analyzed, either at anchor or moored to a quay. Length estimates in optical 5 m resolution images can be obtained with a standard error of 1.3 m (0.25 times the resolution); width estimates with 0.7 m error. In radar images at 8 m single-look resolution, the standard error for length estimates is 12 m (1.5 times the resolution) and for width estimates 4 m, both with an overestimation bias of 5 m.