Matrix array inspections in NDT: 3D imaging with the Virtual Array method

While ultrasound testing (UT) with linear transducer arrays is a widely used method in Non-destructive Testing (NDT), the use of matrix arrays is not so widespread in the field. Nevertheless, matrix arrays can be used to do volumetric imaging without the need to displace the transducer. Furthermore, they provide a solution to the lack of resolution in the elevation direction characteristic of linear arrays, and the possibility to steer the beam in every direction in space. In this work, we propose an optimized auto-focusing algorithm to be used with ultrasound matrix arrays for three-dimensional imaging in the presence of interfaces, as is the case in immersion testing frequently used in NDT.