Application of time-frequency analysis to NDE

In the case of dispersive systems, the velocity dispersion spreads the signal energy all over the time axis and makes the energy localization hard to achieve via commonly used methods. The dispersion relationship can be explicitly expressed using a time-frequency approach. Several time-frequency representations are presented. The following application examples in nondestructive evaluation are shown: surface acoustic wave description, multilayered medium and sonar target characterization, transducer calibration and electrical cable control. >