Reconstructing the back of a defect from its mirror image

A significant problem in the imaging of defects in thick plates is the limited field of view afforded by a linear ultrasound array. This frequently results in inaccurate and incomplete reconstructions. One way of improving the reconstructions is to utilise reflections from the backwall of the component as additional probing waves. We have implemented this approach by modifying the focusing laws used by the inverse scattering methods in order to take the backwall reflections into account. We illustrate the theoretical framework of the proposed method and present reconstructions from both synthetic and experimental data.