Retrieval of the equivalent acoustic constitutive parameters of an inhomogeneous fluid-like object by nonlinear full waveform inversion.

This study addresses the problem of the acoustic characterization of an inhomogeneous object such as a soft-tissue organ containing a cyst or tumor whose size and/or composition evolve either negatively due to increased disease or positively due to increased response to treatment. The so-called 'corrupted' binary object, probed by a transient, acoustic plane wave, is a tube composed of a homogenous fluid-like (or assumed as such) mantle (medium 1: three acoustic constitutive parameters, one geometric parameter) surrounding a homogeneous fluid-like (or assumed as such) core (medium 2: three acoustic constitutive parameters, one geometric parameter), immersed in a spatially-infinite, homogeneous fluid (host medium 0: two acoustic parameters). The complete inversion of the diffracted acoustic field response of this object involves the retrieval of seven (six acoustic and one geometric) parameters, assuming we know beforehand the outer radius of the tube and acoustic parameters of the host.

Acoustic response of a rigid-frame porous medium plate with a periodic set of inclusions.

The acoustic response of a rigid-frame porous plate with a periodic set of inclusions is investigated by a multipole method. The acoustic properties, in particular, the absorption, of such a structure are then derived and studied. Numerical results together with a modal analysis show that the addition of a periodic set of high-contrast inclusions leads to the excitation of the modes of the plate and to a large increase in the acoustic absorption.

Reconstruction of material properties profiles in one-dimensional macroscopically inhomogeneous rigid frame porous media in the frequency domain.

The present paper deals with the inverse scattering problem involving macroscopically inhomogeneous rigid frame porous media. It consists of the recovery, from acoustic measurements, of the profiles of spatially varying material parameters by means of an optimization approach. The resolution is based on the modeling of acoustic wave propagation in macroscopically inhomogeneous rigid frame porous materials, which was recently derived from the generalized Biot's theory.

Ultrasonic characterization of human cancellous bone using the Biot theory: inverse problem.

This paper concerns the ultrasonic characterization of human cancellous bone samples by solving the inverse problem using experimental transmitted signals. The ultrasonic propagation in cancellous bone is modeled using the Biot theory modified by the Johnson et al. model for viscous exchange between fluid and structure.

Inversion of synthetic and experimental acoustical scattering data for the comparison of two reconstruction methods employing the Born approximation.

This work is concerned with the reconstruction, from measured (synthetic or real) data, of a 2D penetrable fluid-like object of arbitrary cross-section embedded in a fluid of infinite extent and insonified by a plane acoustic wave. Green's theorem is used to provide a domain integral representation of the scattered field. The introduction therein of the Born approximation gives rise to a linearized form of the inverse problem.