An application of Wiener filtering to nondestructive evaluation

The inverse problem of defect characterization is carried out by comparing theoretical and experimental return echo pulses. Acoustic echo signals of the order of 2 ns long are digitized and fed into a digital computer. A Wiener filter is designed to match the transducer response, so the impulse response of the system approaches a δ function. Experimental results on defects in Si3N4 ceramics are presented which demonstrate the power of such a technique for defect characterization.