Ultrasonic Imaging of Immersed Objects using Migration Techniques

Inhalt:
The synthetic aperture focusing technique (SAFT) is often used for imaging in non-destructive ultrasonic testing. Conventional SAFT is well suited for contact testing of homogeneous objects because of the constant sound speed throughout the media, whereas the refraction present in the practically important case of immersion tests has so far prevented a widespread use of SAFT for such data. Fortunately, the problem of imaging layered objects has been extensively treated in geophysics where migration is used routinely for this kind of problems. This paper shows how such techniques can also be successfully applied to data from ultrasonic immersion tests.