Method and system for non-invasively characterizing a heterogeneous medium using ultrasound

System for non-invasive ultrasonic characterization of a heterogeneous medium, the system comprising:

• a first array of transducers suitable for generating a series of incident ultrasonic waves in a region of the heterogeneous medium, said series of incident ultrasonic waves constituting an input emission basis (i), and suitable for recording as a function of time the ultrasonic waves backscattered by said region;
• and
• a computing unit coupled to the first array of transducers and configured for:
• recording an experimental reflection matrix Rui(t) defined between the input emission basis (i) and an output reception basis (u);
• determining a response REP(r,Δr) of the medium between an input virtual transducer (TVin) of spatial position rin calculated based on an input focusing of the experimental reflection matrix corresponding to an input focal spot around a first point (P1) and an output virtual transducer (TVout) of spatial position rout calculated based on an output focusing of the experimental reflection matrix corresponding to an output focal spot around a second point (P2),
• said response REP(r,Δr) being expressed as a function of a central point (PC) of spatial position r in the medium and as a function of a distance coordinate Δr from said central point,
• said central point (PC) being located midway between the first and second points (P1, P2) such that r=(rout+rin)/2 and such that Δr=(rout−rin)/2, and
• said central point (PC) being the origin of a measurement axis (AXm) passing through said first and second point s (P1, P2), said measurement axis (AXm) forming an angle β relative to a first axis (X) of the medium, and
• the first point (P1) being at the distance coordinate +Δr on the measurement axis (AXm), and the second point (P2) being at an opposite distance coordinate −Δr on the measurement axis (AXm).