Characterization of elastic shells by the use of the wavelet transform

Ginette Saracco (1, 2) , Philippe Guillemain (1) , Richard Kronland-Martinet (1)

1 LMA - Laboratoire de Mécanique et d'Acoustique [Marseille]
2 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement

This paper concerns the characterization of elastic targets immersed in a fluid and submitted to an acoustic impulse. Time-frequency methods have already been used in the case of scatterers of simple geometric shape. We have chosen the wavelet transform for its particular properties, such as linearity aand local analysis at Df/f=Cst. We have developped an algorithm based on the behavior of the phase of the transform, which enables us to extract modulation laws (related to the dispersion law of the phase velocity), even for close echoes. In the case of spherical elastic shells, we have applied this method on both experimental and computer-generated signals and have pointed out the good relation between theoretical and experimental results.

Mots clés: Complex wavelet transform; ridge; skeleton; frequency modulation laws; amplitude modulation laws; asymptotic wavelet; spectral line; scattering; elastic shells; stationary phase; phase and group velocity

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Ginette Saracco, Philippe Guillemain, Richard Kronland-Martinet. Characterization of elastic shells by the use of the wavelet transform. Ultrasonics Symposium, Dec 1990, Honolulu, United States. pp.881-885. ⟨hal-00177246⟩