Abstract: The invention relates to systems and methods for conducting an ultrasonic, nondestructive evaluation and inspection of a pipe using Lamb-type wave transducers to detect the presence of defects, flaws, discontinuities and the like. The transducers are positioned within the interior space of the pipe. Two transducers are positioned facing each other such that the ultrasonic beam emitted from each of the transducers is directed toward the other transducer and the portion of pipe to be inspected. The coverage of the transducers is verified and the results are processed using a combination of a cross correlation filter and a signal processing tool.

Abstract: An ultrasonic testing system can receive data from at least two ultrasonic transducers and process the data in parallel to each other. The testing system can compress the data by a fixed ratio by storing the value of the sample having the highest-amplitude out of a group of samples. The testing system can also provide threshold-based run-length encoding by compressing data by only storing samples which exceed a user-defined threshold value as well as a user-defined range of samples surrounding said samples. The ultrasonic testing system also provides a hardware gate for storing a peak amplitude and associated time-of-flight for a user-defined interval and a gate for storing the time-of-flight for the first excursion of the data through a user-defined threshold and interval. The operation of these gates or the storage of waveform data may be delayed by a constant delay or until the data exceeds a user-selectable threshold during a user-selectable time interval.

Abstract: To improve and simply ultrasonic measurement of thin layers, an adaptive least-mean-square (LMS) implementation of a Wiener filter is used to deconvolve ultrasonic waveforms. This filter is structured as a finite-impulse-response (FIR) filter and solved using Widrow's adaptive linear combiner. The filter is implemented on a microcomputer with gating features for automated signal peak identification and measurement. The deconvolution process begins by assuming an impulse (the desired response) to a known input (the ultrasonic response). A transfer function is then determined that, when convolved with the response, results in the assumed impulse. The transfer function in this case is a long FIR filter typically requiring up to 128 taps to achieve acceptable results.

Abstract: An eddy current imaging system includes an eddy current sensing coil positioned proximate a workpiece for scanning the workpiece to produce a signal indicative of the integrity of the workpiece for regions in an x,y array of data. Such a signal may be a complex impedance signal representative of the amplitude and/or the phase of the signal. Two data processing techniques are disclosed for enhancing the display of a flay in the workpiece. The first includes the step of calculating a spatial derivative of the amplitude and/or phase indicative signal from the coil and providing an image of the spatial derivative to produce a C scan of the spatial derivative. The second includes the steps of determining the regions of maximum ascent and/or descent of the signal for regions in the scan and calculating an impedance plane trajectory from the data array of path points for displaying a reconstructed optimum signal independent of path pattern.