SAFT processing of noncontact ultrasonic NDE data

Ultrasonic data have been obtained by scanning a pulsed EMAT (electromagnetic acoustic transducer) detector over the surface of an aluminum sample containing artificial defects. The annular EMAT was concentric with the source to imitate pulse-echo systems. Reflection data were processed using SAFT (synthetic-aperture focusing technique) methods, to give images of the defects. Details are given on modifications to the usual SAFT approach, to compensate for the finite EMAT aperture.<
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