Synthetic Aperture Focusing and Time-of-Flight Diffraction Ultrasonic Imaging—Past and Present

The detection of defects in materials and components using ultrasonic nondestructive testing and evaluation techniques is of interest in many industrial areas. Reliable defect detection requires defined and reproducible scanning of the probes along the surface of the components. For post-processing of the recorded rf-data the Synthetic Aperture Focusing Technique SAFT has been successfully applied to improve the performance of ultrasonic testing. For specific defect and component configurations, the Time-of-Flight Diffraction technique TOFD has also been successfully applied for quantitative evaluation of crack sizes. This contribution reviews developments and applications of SAFT and TOFD with reference to representative examples from the past and the present.