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Synthetic Focusing of Sound Beam Using Linear Array

A sound beam focusing technique called synthetic focusing using linear array (SFLA) has been developed. The technique is based on acquiring the raw B-scan image using a divergent sound beam emanating from individual elements of an array and then carrying out synesthetic aperture focusing technique (SAFT) processing of the raw data to achieve sound beam focusing throughout the thickness of the sample. The sound beam focusing is achieved using much less advanced resources as compared to the focal law based phased array technique. The data size for post processing is also significantly smaller as compared to the one acquired using full matrix capture (FMC). The sensitivity for the detection of discontinuities and the ability to resolve them from each other using SFLA technique has been assessed on aluminum and carbon steel samples. The results obtained by SFLA technique have been found to be comparable to those obtained by the full matrix capture – total focusing method (FMC + TFM). The focusing ability of SFLA technique has been utilized for accurate depth sizing of a planar flaw in the weld joint.

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