Review on Ultrasonic Techniques for Underwater Object Classification
|Pooja Gavande1, Dr. R.S.Kawitkar2, M. Selva Balan3
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Underwater object classification is an attractive approach using acoustic remote sensing techniques due to its high coverage capabilities and limited costs as compared to manual method of taking samples from the seafloor. This review paper focuses on the characterization of underwater objects in a coastal environment using different ultrasonic techniques like multibeam echosounder (MBES), a single-beam echosounder (SBES) and sidescan sonar(SSS). Out of these ultrasonic techniques, MBES and SBES are, in general, high-frequency techniques providing information about bathymetry and backscatter for the upper part of the sea bottom. MBES systems provide this information with a better resolution due to the beam opening angle of typically 1 –3 , and high coverage. An SBES provides measurements directly underneath the ship only, but is widespread. For MBES underwater object classification is achieved through the Bayesian approach, employing backscatter measurements per beam. For the SBES, echo shape parameters of the transmitted signal are determined and are combined in a principal component analysis (PCA). Underwater object classification using these ultrasonic techniques is useful for a large range of applications, such as habitat mapping, cable laying, or mine hunting.