“…However, the use of a single array element in emitting stage has some limitations, the most significant are formation of grating lobes and low SNR. These problems can be solved using virtual sources [13] for increasing the acoustic energy or the Total Focusing Method (TFM), which combines the emission of one array element with simultaneous reception of all the array elements. In this way a better SNR is achieved, the sidelobes and grating lobes are reduced and the probability of detection of defects increases regardless of their orientation.…”