Document Detail

Reliable estimation of virtual source position for SAFT imaging.
MedLine Citation:
PMID:  23357909     Owner:  NLM     Status:  In-Data-Review    
The synthetic aperture focusing technique (SAFT), employing a scanned focused transducer as a virtual source, is commonly used to image flaws in immersion testing. The position of a virtual source is estimated from rays emitted from the rim of a focused transducer. However, it is often found that the virtual source position cannot be uniquely determined because of severe focal spot aberration at the focal zone. Based on an analysis of the energy radiated from the focused transducer and the refracted energy varied with the incident angle of ultrasound, we propose that paraxial rays emitted from the focused transducer are the best for estimating the position of a virtual source for incorporation into SAFT. This study results also shows that by using this simple virtual source position estimation for SAFT, the axial resolution and SNR of the reconstructed image can be greatly improved. This new approach minimizes the effect of such factors as refraction at high-velocity-contrast interfaces, distance of the transducer to the couplant-specimen interface, and the focal length of a focused transducer, which may cause focal spot aberration resulting in decreased sensitivity in SAFT imaging.
Chih-Hsiung Chang; Young-Fo Chang; Yushieh Ma; K Shung
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  IEEE transactions on ultrasonics, ferroelectrics, and frequency control     Volume:  60     ISSN:  1525-8955     ISO Abbreviation:  IEEE Trans Ultrason Ferroelectr Freq Control     Publication Date:  2013 Feb 
Date Detail:
Created Date:  2013-01-29     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9882735     Medline TA:  IEEE Trans Ultrason Ferroelectr Freq Control     Country:  United States    
Other Details:
Languages:  eng     Pagination:  356-63     Citation Subset:  IM    
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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