Calibration method for guided elastic wave tomography adapted to cylinder-type structures

A device for performing tomography, comprising an array of elastic-wave sensors (CP) that are intended to be positioned on a surface of a structure to be imaged and a processing unit that is configured for:

• receiving signals measured by the elastic-wave sensors;
• measuring a plurality of signals propagating through the structure with a plurality of pairs of non-collocated elastic-wave sensors;
• for each pair of elastic-wave sensors,
• i. selecting one guided elastic wave propagation mode,
• ii. converting the measured signals into wave fields for the selected guided elastic wave propagation mode, and
• iii. determining an anisotropic calibration coefficient from a wave-field propagation model evaluated depending on an anisotropic wavenumber, a distance between the elastic-wave sensors of the pair, and said wave fields or a reference wave field corresponding to a healthy state of the structure;
• calibrating the wave fields using the determined calibration coefficients;
• performing diffraction tomography on the structure from the calibrated wave fields;
• and
• displaying, on an interface, an image of the structure obtained from the diffraction tomography.