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Proceedings Paper

Ultrasonic imaging using wave structure-based weights and global matched coefficients
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Paper Abstract

In the field of non-destructive evaluation of structures, 2D and 3D imaging of internal flaws is a critical task. Defect imaging allows making informed follow-up decisions based on the morphology of the flaw. This paper will present advances in ultrasonic tomography for the 2D and 3D visualization of internal flaws in solids. In particular, improvements to the conventional tomographic imaging algorithms have been made by utilizing a mode-selective image reconstruction scheme that exploits the specific displacement field, respectively, of the longitudinal wave modes and the shear wave modes, both propagating simultaneously in the test volume. The specific mode structure is exploited by an adaptive weight assignment to the ultrasonic tomographic array. Such adaptive weighting forces the imaging array to look at a specific scan direction and better focus the imaging onto the actual flaw (ultrasound reflector). Moreover, the introduction of a global matched coefficient, computed through the matching of measured and expected times of flight for each pixel, is illustrated. The benefits deriving from the application of this coefficient to conventional imaging frameworks are shown. This study shows that the adaptive weighing based on wave structure and the integration of the global matched coefficient improve image contrast and resolution compared to a conventional ultrasonic imaging technique based on a delay-and-sum or minimum variance distortionless method. Results will be shown from experimental tests of simulated flaws in solids.

Paper Details

Date Published: 1 April 2016
PDF: 16 pages
Proc. SPIE 9805, Health Monitoring of Structural and Biological Systems 2016, 980527 (1 April 2016); doi: 10.1117/12.2218931
Show Author Affiliations
Simone Sternini, Univ. of California, San Diego (United States)
Thompson Vu Nguyen, Univ. of California, San Diego (United States)
Francesco Lanza di Scalea, Univ. of California, San Diego (United States)

Published in SPIE Proceedings Vol. 9805:
Health Monitoring of Structural and Biological Systems 2016
Tribikram Kundu, Editor(s)

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