Ultrasonic arrays are well known for their ability to image the interior of the human body for medical diagnostics. However my work concerns their application to imaging the interior of engineering structures, such as aircraft, water pipelines and wind turbines. For engineering structures, the challenge is to find small defects, usually cracks, before they grow to the point where they undermine safety. Indeed, operators of safety critical structures are legally obliged to perform some kind of imaging. What everyone wants to know is how long is it safe to operate the structure for? So, the equation is simple, better quality information about the state of a structure, leads to better remaining life predictions and hence delivers safer structures.
My work in this area started many years ago when I (in collaboration with Paul Wilcox) investigated the use of a new approach to array imaging. This we termed full matrix capture (FMC). The idea is very simple. The array data is first collected and stored and then post-processed on a computer to produce high resolution images or extract other information. We first explored an imaging algorithm which we called the total focusing method (TFM) in which a focus is synthetically produced at every pixel in the image. This basic approach is now in widespread use in academia and industry. It is also described in detail in a new book.