Using phase information to enhance speckel noise reduction in the ultrasonic NDE of coarse grain materials

Timothy Lardner, Minghui Li, Anthony Gachagan

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

4 Citations (Scopus)

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.
Original languageEnglish
Title of host publication40th Annual Review of Progress in Quantitative Nondestructive Evaluation
Subtitle of host publicationIncorporating the 10th International Conference on Barkhausen Noise and Micromagnetic Testing
EditorsDale E. Chimenti, Leonard J. Bond, Donald O. Thompson
Place of PublicationMelville, NY
Volume1581
DOIs
Publication statusPublished - 18 Feb 2014
Event40th Annual Review of Progress in Quantitative Nondestructive Evaluation: Incorporating the 10th International Conference on Barkhausen Noise and Micromagnetic Testing - Baltimore, United States
Duration: 21 Jul 201326 Jul 2013

Conference

Conference40th Annual Review of Progress in Quantitative Nondestructive Evaluation: Incorporating the 10th International Conference on Barkhausen Noise and Micromagnetic Testing
CountryUnited States
CityBaltimore
Period21/07/1326/07/13

Keywords

  • coarse grain materials
  • phase information
  • speckel noise reduction
  • ultrasonic NDE

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    Lardner, T., Li, M., & Gachagan, A. (2014). Using phase information to enhance speckel noise reduction in the ultrasonic NDE of coarse grain materials. In D. E. Chimenti, L. J. Bond, & D. O. Thompson (Eds.), 40th Annual Review of Progress in Quantitative Nondestructive Evaluation: Incorporating the 10th International Conference on Barkhausen Noise and Micromagnetic Testing (Vol. 1581). https://doi.org/10.1063/1.4864938