Parabola detection using matched filtering for ultrasound B-scans

Time of flight diffraction (ToFD) outputs B-scans using an ultrasound emitter and receiver at a constant separation, scanned over a sample surface parallel to the line between the transducers. The B-scan, with time and scan position axes, contains parabolic features characteristic of a point-like scatterer. Human vision effectively detects these shapes, but this is time consuming and requires training. A parabola matched filter has been developed that is simple to implement and transforms parabolic shapes to peaks whilst reducing noise in the scan. The scan can then be displayed as depth versus lateral position.

► A parabola matched filter transforms parabolic shapes to peaks whilst reducing noise. ► It is simple to implement the filter as it is based on standard cross-correlation. ► Transformed peak size is dominated by the temporal width of the original feature. ► B-scan axes become depth versus lateral position for defect positioning.