Shadow enhancement in synthetic aperture sonar imagery for improved target classification
conference paper
The acoustic shadow of a target is a strong classification clue in naval mine hunting. A shadow of bottom targets appears at relatively short ranges (≤ about 200 m) in high resolution images from sidescan or synthetic aperture sonar (SAS), against a background of sea floor reverberation. In SAS however, definition of the shadow reduces with increasing synthetic aperture length, which is a measure of image resolution. This effect is similar to an optical shadow that is diffuse when an extended light source is used, but sharp with a point source. The longer the light source (the optical equivalent of the synthetic aperture), the more blurred the shadow becomes. This paper presents a SAS technique that enhances the shadow from a detected target by compensating blurring of the shadow in the image forming process. The proposed method intends to get the best of both worlds: good SAS resolution and good shadow definition. The method is tested on the basis of simulations and real data. It is conluded that automatic shadow contour detection is improved.
Topics
TNO Identifier
219173
Publisher
Foundation for Research & Technology
Source title
Proceedings First International Conference Underwater Acoustic Measurements, Technologies and Results, 28 June - 1 July 2005, Heraklion, Crete, Greece
Editor(s)
Papadakis, J.S.
Bjorno, L.
Bjorno, L.
Place of publication
Hellas, Greece
Files
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