Elastic-wave-based synthetic aperture focusing technique imaging system for detecting voids inside concrete structures

2016 ◽  
Vol 24 (8) ◽  
pp. e1956 ◽  
Author(s):  
Jian-Hua Tong ◽  
Chin-Lung Chiu
Keyword(s):  
Elastic Wave ◽  
Imaging System ◽  
Concrete Structures ◽  
Synthetic Aperture ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique

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.

Synthetic Aperture Focusing Technique and Contrast Source Inversion Algorithm Applied in Elastic Wave Imaging

2011 ◽  
Vol 340 ◽  
pp. 402-408 ◽  
Author(s):  
Ji Qi ◽  
Jing Hong Miao ◽  
Yu Xin Xie
Keyword(s):  
Acoustic Wave ◽  
Elastic Wave ◽  
Synthetic Aperture ◽  
Source Inversion ◽  
Inversion Algorithm ◽  
Wave Data ◽  
Contrast Source Inversion ◽  
Wave Imaging ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique

In this paper the linear synthetic aperture focusing technique (SAFT), the nonlinear contrast source inversion (CSI) algorithm and the CSI algorithm with extended approaches, such as frequency approach and regularization approach, are applied to reconstruct a complicated target immersed in water from the experimental elastic wave data. The inversion results from these datasets using multi-bistatic measurement, which are obtained in the acoustic wave case and the pressure and vertically polarized shear (P-SV) wave case, verify the CSI algorithm with extended approaches is an accurate and promising method for elastic wave imaging.

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