Optimized excitation for nonlinear wave propagation in complex media: From biomedical acoustic imaging to nondestructive testing of cultural heritage

Abstract

The interaction between an acoustic wave and a complex media has an increase interest for both nondestructive testing (NDT) applications and for biomedical ultrasound. Today, new optimized excitations are generated thanks to the analysis of symmetry properties of the system such as reciprocity, nonlinear time reversal (TR) and other pulse-inverted (PI) techniques. Generalized TR based NEWS (Nonlinear Elastic Wave Spectroscopy) methods and their associate symmetry skeleton will be taken as an example. Among these family of “pulse coded excitation,” solitonic coding constitutes a new scheme in the sense that solitary waves are the best candidates for pulse propagation in nonlinear and layered media, such as tooth or skin. As another application of mixing properties in a wide frequency range, new broadband techniques are needed in the domain of the preservation of cultural heritage. The analysis of the composition of the stones is one of the key parameters in the study of aging historic buildings. The use of TR-NEWS based analysis combined with a FTIR-based system has shown a specific property of the tuffeau limestone where damaged sample contains calcite. In both domains, aging properties of complex medium are extracted thanks to the use of enhanced nonlinear signal processing tools.

A research and modeling of wave processes at the scattering of nonlinear acoustic waves on cylindrical bodies

“…The work Dos Santos et al, (2015), is devoted to the use of nonlinear wave spectroscopy for biomedical ultrasound diagnostics. Various modes of propagation of acoustic pulses in nonlinear and layered media are considered.…”

Non-destructive imaging of marqueteries based on a new infrared-terahertz fusion technique

“…In this regard, an imaging approach, as to view and thus determine the location of splitting inside the sample under test, is required. During the inspection of artworks, a variety of imaging techniques have been utilized, including ultraviolet fluorescence [4], [5], acoustic imaging [6], X-ray [7], infrared thermography [8], among other approaches. Fluorescence imaging is a technique for determining the state of paint surfaces and varnish layers.…”