Clutter noise reduction for phased array imaging using frequency-spatial polarity coherence

Gongzhang, Rui and Gachagan, Anthony and Xiao, Bo; Chimenti, Dale E. and Bond, Leonard J., eds. (2015) Clutter noise reduction for phased array imaging using frequency-spatial polarity coherence. In: 41st Annual Review of Progress in Quantative Nondestructive Evaluation. AIP Conference Series, 34 . AIP Publishing, USA, pp. 1648-1656. ISBN 9780735412927 (https://doi.org/10.1063/1.4914786)

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Abstract

A number of materials used in industry exhibit highly-scattering properties which can reduce the performance of conventional ultrasonic NDE approaches. Moving Bandwidth Polarity Thresholding (MBPT) is a robust frequency diversity based algorithm for scatter noise reduction in single A-scan waveforms, using sign coherence across a range of frequency bands to reduce grain noise and improve Signal to Noise Ratio. Importantly, for this approach to be extended to array applications, spatial variation of noise characteristics must also be considered. This paper presents a new spatial-frequency diversity based algorithm for array imaging, extended from MBPT. Each A-scan in the full matrix capture array dataset is partitioned into a serial of overlapped frequency bands and then undergoes polarity thresholding to generate sign-only coefficients indicating possible flaw locations within each selected band. These coefficients are synthesized to form a coefficient matrix using a delay and sum approach in each frequency band. Matrices produced across the frequency bands are then summed to generate a weighting matrix, which can be applied on any conventional image. A 5MHz linear array has been used to acquire data from both austenitic steel and high nickel alloy (HNA) samples to validate the proposed algorithm. Background noise is significantly suppressed for both samples after applying this approach. Importantly, three side drilled holes and the back wall of the HNA sample are clearly enhanced in the processed image, with a mean 133% Contrast to Noise Ratio improvement when compared to a conventional TFM image.

  • Item type:Book Section
    ID code:57372
    Dates:
    Date
    Event
    31 March 2015
    Published
    Notes:This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Gongzhang, R., Gachagan, A., & Xiao, B. (2015). Clutter noise reduction for phased array imaging using frequency-spatial polarity coherence. In D. E. Chimenti, & L. J. Bond (Eds.), 41st Annual Review of Progress in Quantative Nondestructive Evaluation. (Vol. 34, pp. 1648-1656). (AIP Conference Series; Vol. 1650). AIP Publishing and may be found at https://dx.doi.org/10.1063/1.4914786 .
    Subjects:Technology > Electrical engineering. Electronics Nuclear engineering
    Department:Faculty of Engineering > Electronic and Electrical Engineering
    Depositing user: Pure Administrator
    Date deposited:11 Aug 2016 10:39
    Last modified:08 Apr 2024 13:27
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/57372
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