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Title: Using phase information to enhance speckle noise reduction in the ultrasonic NDE of coarse grain materials

Abstract

Materials with a coarse grain structure are becoming increasingly prevalent in industry due to their resilience to stress and corrosion. These materials are difficult to inspect with ultrasound because reflections from the grains lead to high noise levels which hinder the echoes of interest. Spatially Averaged Sub-Aperture Correlation Imaging (SASACI) is an advanced array beamforming technique that uses the cross-correlation between images from array sub-apertures to generate an image weighting matrix, in order to reduce noise levels. This paper presents a method inspired by SASACI to further improve imaging using phase information to refine focusing and reduce noise. A-scans from adjacent array elements are cross-correlated using both signal amplitude and phase to refine delay laws and minimize phase aberration. The phase-based and amplitude-based corrected images are used as inputs to a two-dimensional cross-correlation algorithm that will output a weighting matrix that can be applied to any conventional image. This approach was validated experimentally using a 5MHz array a coarse grained Inconel 625 step wedge, and compared to the Total Focusing Method (TFM). Initial results have seen SNR improvements of over 20dB compared to TFM, and a resolution that is much higher.

Authors:
;  [1];  [2]
  1. Centre for Ultrasonic Engineering, University of Strathclyde, Glasgow, G1 1XW (United Kingdom)
  2. School of Engineering, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)
Publication Date:
OSTI Identifier:
22263734
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1581; Journal Issue: 1; Conference: 40. annual review of progress in quantitative nondestructive evaluation, Baltimore, MD (United States), 21-26 Jul 2013, 10. international conference on Barkhausen noise and micromagnetic testing, Baltimore, MD (United States), 21-26 Jul 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; CORROSION; IMAGES; INCONEL 625; NOISE

Citation Formats

Lardner, Timothy, Gachagan, Anthony, and Li, Minghui. Using phase information to enhance speckle noise reduction in the ultrasonic NDE of coarse grain materials. United States: N. p., 2014. Web. doi:10.1063/1.4864938.
Lardner, Timothy, Gachagan, Anthony, & Li, Minghui. Using phase information to enhance speckle noise reduction in the ultrasonic NDE of coarse grain materials. United States. https://doi.org/10.1063/1.4864938
Lardner, Timothy, Gachagan, Anthony, and Li, Minghui. 2014. "Using phase information to enhance speckle noise reduction in the ultrasonic NDE of coarse grain materials". United States. https://doi.org/10.1063/1.4864938.
@article{osti_22263734,
title = {Using phase information to enhance speckle noise reduction in the ultrasonic NDE of coarse grain materials},
author = {Lardner, Timothy and Gachagan, Anthony and Li, Minghui},
abstractNote = {Materials with a coarse grain structure are becoming increasingly prevalent in industry due to their resilience to stress and corrosion. These materials are difficult to inspect with ultrasound because reflections from the grains lead to high noise levels which hinder the echoes of interest. Spatially Averaged Sub-Aperture Correlation Imaging (SASACI) is an advanced array beamforming technique that uses the cross-correlation between images from array sub-apertures to generate an image weighting matrix, in order to reduce noise levels. This paper presents a method inspired by SASACI to further improve imaging using phase information to refine focusing and reduce noise. A-scans from adjacent array elements are cross-correlated using both signal amplitude and phase to refine delay laws and minimize phase aberration. The phase-based and amplitude-based corrected images are used as inputs to a two-dimensional cross-correlation algorithm that will output a weighting matrix that can be applied to any conventional image. This approach was validated experimentally using a 5MHz array a coarse grained Inconel 625 step wedge, and compared to the Total Focusing Method (TFM). Initial results have seen SNR improvements of over 20dB compared to TFM, and a resolution that is much higher.},
doi = {10.1063/1.4864938},
url = {https://www.osti.gov/biblio/22263734}, journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1581,
place = {United States},
year = {Tue Feb 18 00:00:00 EST 2014},
month = {Tue Feb 18 00:00:00 EST 2014}
}