Digital Signal-Processing Techniques Used for Improving the Resolution of B-Scans in 1 Second or Less Per Waveform

摘要

The application of several signal-processing techniques for improved resolution of ultrasonic B-scans is complete. Techniques such as split-spectrum processing, analytic-signal magnitude, and various windowing procedures have been implemented. A transducer pulser and receiver are used in conjunction with a data acquisition system to send, receive, digitize, and store ultrasonic waveforms. The digitized waveforms are processed using an array processor. The results have proved favorable both in processing time and in additional information provided by the techniques. The array processor is installed in a DEC 11/23 computer and is accessed using simple Fortran calls. All of the processing techniques require at least 2 FFTs and one of them, split-spectrum processing, requires as many as 20 FFTs per waveforms. Even with this extensive computation each technique is implemented in 1 second or less. (ERA citation 08:030135)