Figure 12 – Schematic drawing of electronic scanning.
Electronic focusing: this pattern is show in figure 13. Electronic focusing is based on the use of different time delays applied on phased array probe transmission or reception in a way to focalize the summed beam at a depth, similarly as obtained with acoustic lenses.
Figure 13 – Schematic drawing of electronic focusing. Electronic focalization permits to use of only one Phased Array probe (with several individual elements) spite of several traditional UT probes (only one element) with different focal depths. This pat-tern is normally used in thick plate inspection.
Sectorial scanning (also called azimuthal or angular scanning) (figure 14): the beam is moved through a sweep range for a specific focal depth, using the same elements; other sweep ranges with different focal depths may be added. The angular sectors may have different values. Electronic focusing permits that only one probe (Phased Array) is used in place of several conventional UT probes with different incidence angles. Additionally steering can be obtained without the use of a wedge, accessing restricted piece areas. All the patterns cited can be combined to solve complex inspection problems.