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Proceedings Paper

An autofocus algorithm for flexible ultrasonic arrays based on maximisation of image contrast
Author(s): Alan J. Hunter; Bruce W. Drinkwater; Paul D. Wilcox
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Paper Abstract

This paper presents an algorithm for autofocusing imagery obtained from a flexible ultrasonic array with unknown geometry. The relative positions of the array elements are parameterised using a polynomial function. The polynomial coefficients are estimated by iterative maximisation of the SAFT image contrast via simulated annealing. The estimate can be refined in the final stages of iteration using the full 3-D matrix of echo data via the total focusing method. The resultant polynomial gives an estimate of the array geometry and the profile of the surface that it has conformed to, providing a well-focused, high quality image. The algorithm is demonstrated on experimental data obtained using a flexible array prototype.

Paper Details

Date Published: 10 April 2008
PDF: 11 pages
Proc. SPIE 6935, Health Monitoring of Structural and Biological Systems 2008, 69350Z (10 April 2008); doi: 10.1117/12.776241
Show Author Affiliations
Alan J. Hunter, Univ. of Bristol (United Kingdom)
Bruce W. Drinkwater, Univ. of Bristol (United Kingdom)
Paul D. Wilcox, Univ. of Bristol (United Kingdom)

Published in SPIE Proceedings Vol. 6935:
Health Monitoring of Structural and Biological Systems 2008
Tribikram Kundu, Editor(s)

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