Sounding method and device using wave propagation

摘要

The invention relates to a wave-propagation-based sounding method, in which: an incident wave is emitted through a medium including diffusers capable of reflecting the wave; and, subsequently, signals representing a reflected wave reverberated by the medium from the incident wave are captured, said captured signals being the sum of a single scattering component and a multiple scattering component. The captured signals are processed by separating the multiple scattering component from the single scattering component by filtering at least one frequency transfer matrix representing responses between transducers from the transducer assembly.

主权项

1. A wave-propagation probing method using an array of transducers, said method comprising:
(a) a transmission step during which the transducer array transmits an incident wave into a medium that scatters said wave; (b) a measurement step during which said transducer array captures signals representative of a reflected wave reverberated by the medium on the basis of the incident wave, said captured signals comprising:
a single scattering component representative of wave paths in which the reflected wave results from a single reflection of the incident wave by each scatterer in the medium, anda multiple scattering component representative of wave paths in which the reflected wave results from several successive reflections of the incident wave by the scatterers in the medium before reaching the transducer array; and (c) a processing step during which said captured signals are processed using a central processing unit (CPU) so as to determine characteristics of the medium,wherein, during the processing step (c), at least one component chosen from the multiple scattering component and the single scattering component is extracted, by filtering at least one frequency transfer matrix representative of the responses between transducers of the transducer array,
wherein the processing step (c) comprises at least the following substeps: (c1) a windowed transfer matrix determination substep during which at least one windowed frequency transfer matrix K(T,f)=[kij(T,f)], corresponding to a windowed temporal inter-element response matrix K(T,t)=[kij(T,t)], is determined, said windowed temporal inter-element response matrix corresponding, over a neighboring temporal window of time T and duration Δt, to the temporal responses hij(t) between transducers of the transducer array, f being the frequency; (c3) a filtering substep during which the multiple scattering component is separated from the single scattering component in each windowed frequency transfer matrix K(T,f) as a function of the coherence of the coefficients kij(T,f) of the windowed frequency transfer matrix K(T,f) along each antidiagonal of said windowed frequency transfer matrix K(T,f).