Target classification near complex interfaces using time-frequency filters

This paper presents a method for target recognition and classification in a shallow water environment. It is based on time-frequency filtering matched to a free field reference target response. The decision strategy lies on the comparison of the reference and the filter output signal. The method is applied to an experimental data base containing target acoustic responses measured in a tank for typical configurations (free field, semi-infinite space and waveguide). First, the recognition of a spherical shell is carried out. The obtained rate of recognition and confusion are more than encouraging. Then, a classification procedure is conducted and a degradation of the mean performances is to be noted in the more general case. However, the classification of 3D targets independently of their attitude gives quite satisfactory results.