An Implementation of Synthetic Aperture Focusing Technique in Frequency Domain

2007 ◽  
Vol 54 (7) ◽  
pp. 1399-1408 ◽  
Author(s):  
Tadeusz Stepinski
Keyword(s):  
Frequency Domain ◽  
Synthetic Aperture ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique

The Frequency-Domain Algorithm for Ultrasonic Imaging of Complex-Shaped Objects

2018 ◽  
Vol 769 ◽  
pp. 262-268
Author(s):  
Dmitry Dolmatov ◽  
Dmitriy A. Sednev ◽  
Roman Pinchuk
Keyword(s):  
Frequency Domain ◽  
Ultrasonic Imaging ◽  
Ultrasonic Waves ◽  
Synthetic Aperture ◽  
The Novel ◽  
Suggested Technique ◽  
Waves Propagation ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique

The algorithms based on Synthetic Aperture Focusing Technique are aimed at the determination of the imageries of the flaws in controlled objects. Ultrasonic imaging of complex-shaped objects requires specific algorithms which are able to take into account the complicated character of ultrasonic waves propagation. In this article, we suggested the novel frequency-domain algorithm for ultrasonic imaging of complex-shaped objects. This algorithm is based on Phase –shift migration theory and Stolt transform. The evaluation of suggested technique was done by the application of raw ultrasonic data which was obtained by using computer simulations. Derived results show that proposed algorithm is able to make accurate and precise imaging of flaws in complex-shaped objects.

Time Domain/Frequency Domain SAFT Imaging in Thin-Diameter Rod

2013 ◽  
Vol 380-384 ◽  
pp. 3648-3652 ◽  
Author(s):  
Gao Yuan Zhao ◽  
Chao Lu
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Signal To Noise Ratio ◽  
Synthetic Aperture ◽  
Testing Device ◽  
Signal To Noise ◽  
Ultrasonic Flaw ◽  
Reflected Signal ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique

The ultrasonic flaw reflected signal of the thin-diameter rod was acquired by the general ultrasonic C-scan testing device. And synthetic aperture focusing technique be used in ultrasonic imaging of thin-diameter rod. Respectively, Comparing B-scan imaging and Conventional synthetic aperture focusing technique imaging as well as Frequency domain synthetic aperture focusing technique imaging . The final results show that both time domain and frequency domain synthetic aperture method could obtain a higher signal-to-noise ratio and testing resolution.

ULTRASONIC IMAGING SYSTEM USING A 2D ENVELOPE BEAMFORMING TECHNIQUE: IN-HOMOGENEITIES LOCATION

2004 ◽  
Vol 12 (04) ◽  
pp. 571-585
Author(s):  
L. MEDINA ◽  
E. MORENO
Keyword(s):  
Imaging System ◽  
Side Lobe ◽  
Ultrasonic Pulse ◽  
Image Resolution ◽  
Synthetic Aperture ◽  
Water Tank ◽  
Synthetic Aperture Focusing ◽  
Longitudinal Resolution ◽  
Synthetic Aperture Focusing Technique ◽  
Beamforming Technique

An algorithm has been developed to implement synthetic aperture focusing technique for B-scan. This is made at a several transmitter/receiver locations to form a map of ultrasonic reflectivity on the insonified region, considering the path travelled by the ultrasonic pulse from the transducer to the target and back again. To reconstruct the image, a time domain beam-former is applied to the envelope of the detected signals. This method minimizes the side-lobe amplitude and the restriction of λ/2 distance between two adjacent transducer positions can be neglected without loosing image resolution. The present work is focused on the location of the in-homogeneities, caused by the presence of a phantom immersed in a water tank. The results are presented when the distance between two adjacent transducer positions are varied from 0.5λ to 2.5λ showing that the longitudinal resolution is not affected but the lateral resolution becomes poorer when the distance is about 2λ. The error in the longitudinal location of in-homogeneities is within the minimum detectable distance of the system, while the lateral location error is increased when the distance between any two adjacent transducer positions is larger than 1.5λ.

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