Rapid distributed data collection with arrays - The next step beyond full waveform capture

Ultrasonic C-scanning is widely used for large-area flaw detection but acquiring the full RF waveform for each surface point - Full Waveform Capture (FWC) - offers many advantages. A system that used phased arrays to achieve this without loss of area coverage rate has been reported⁽¹⁾. FWC allows many signal processing operations, previously only possible at acquisition, to be performed off-line. Multiple or time-consuming algorithms can be performed on the same data set without compromising inspection speed but some, such as steering and focusing, must still be performed at acquisition. Although ultrasonic arrays are now widely accepted in imaging systems, their full capability will only be realised when viewed as distributed data collection devices⁽²⁾. The modular array hardware of DSL's 'FlawInspecta' can now achieve this at real-time rates, significantly extending the post-processing operations that can be performed. These include steering and focusing adjustments, data-dependent adaptive focusing, and multi-array data collection and processing. A flexible data formatting has been devised to provide an interface for end-users to develop customised algorithms. The paper reports on the distributed data acquisition architecture and the data storage format. Specific post-processing operations are covered elsewhere⁽³⁾ but some typical options will be outlined.