Virtual source aperture imaging for non-destructive testing

In recent years, the adoption of linear array transducers and the use of synthetic aperture imaging has expanded considerably for non-destructive testing, leading to the introduction of the full matrix capture data acquisition technique and the total focusing method. Based on the underlying principles of the synthetic aperture focusing technique, it is capable of producing higher resolution images, but at the cost of lower frame rates. For time-critical inspections, this paper outlines an alternative synthetic aperture method, termed virtual source aperture (VSA). To measure performance in terms of speed, full matrix capture synthetic aperture focusing and the virtual source aperture are compared experimentally, where it is shown that the virtual source aperture offers rapid inspection times with images of good lateral resolution and signal-to-noise ratio.