Implementation issues of 3D SAFT in time and frequency domain for the fast inspection of heavy plates

When testing components in production facilities via ultrasound a good focusing of the measurements for the precise identification of inclusions is required. Often, this is obtained in post-processing by the Synthetic Aperture Focusing Technique (SAFT). This approach usually suffers from high computation times. In this paper, we compare approaches for the implementation of SAFT on the example of the inspection of heavy plates, where the fastest possible processing is required in order to allow full inspection in the production line.We tune timeand frequency domain algorithms for the inspection of planar objects and compare them regarding computation cost under the constraint of obtaining a sufficient reconstruction quality. In frequency-domain, we compare two approaches, namely the Phase-shift migration and tuned-versions of Stolt’s migration with different interpolation strategies. In time-domain, we propose and compare heuristics for the delay-and-sum SAFT. We show that algorithm tuning can dramatically reduce computation times without significant degradation of the reconstruction results. Theoretic bounds for computation times and memory requirements related to the parameters of the reconstruction scenario are given and verified by measurements.