Time of Flight Diffraction (TOFD)

The UT-amplitude time-of-flight analysis technique utilizes multiple search units in pulse-echo, transmitter-receiver, or tandem configuration. Individually selectable parameters control the compression of the A-scan information using a pattern-recognition algorithm, so that only the relevant A-scan amplitudes are stored and further processed. These raw data can be displayed in B-, C-, and D-scan (side, top, and end view) presentations, with selectable color-code increments for amplitude and fast zoom capabilities. This operating mode is most suitable for detection purposes.  A two-dimensional spatial-filtering algorithm is applied to search for correlation of the time-of-flight raw data with reflector-typical time-of flight trajectories.

Tandem sizing and analysis uses techniques similar to pulse-echo but provides images that may be easier to interpret since the specular reflections from flaws oriented perpendicular to the surface are used.