Two methods for solving the inverse problem in underwater acoustics

Gerard J. Quentin; Herve Batard; Alain Cand

doi:10.1117/12.138298

16 September 1992 Two methods for solving the inverse problem in underwater acoustics

Gerard J. Quentin, Herve Batard, Alain Cand

Proceedings Volume 1700, Automatic Object Recognition II; (1992) https://doi.org/10.1117/12.138298
Event: Aerospace Sensing, 1992, Orlando, FL, United States

Abstract

We present in this paper two methods of resolution of the Inverse Problem for axisymmetrical targets in Underwater Acoustics. What we mean by recognition is the assessment of the radius of the target and its mechanical properties (sound velocities c_L and c_T and density (Rho) ). The first method is derived from a parametrical study of resonances in cylinders at low frequencies. This study leads to approximate expressions of resonance frequencies x^*₁. These expressions exhibit for most resonances either a dependency of x^*₁ versus the longitudinal sound velocity or versus the shear sound velocity leading to a new classification of resonances taking into account the polarization of the waves involved. The behavior of the widths of the resonances leads also to simple expressions. The results presented will be generalized from the bulk cylinder case to more complicated targets. In order to solve the inverse problem and carry out object recognition, we invert such approximate equations. The second one uses the A* algorithm of Artificial Intelligence and has been successfully applied to the recognition of elastic cylinders at high frequencies. Results will be presented.

Citation Download Citation

Gerard J. Quentin, Herve Batard, and Alain Cand "Two methods for solving the inverse problem in underwater acoustics", Proc. SPIE 1700, Automatic Object Recognition II, (16 September 1992); https://doi.org/10.1117/12.138298

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