Research on SAFT Imaging Method of Array Probes in Concrete Structures

2012 ◽  
Vol 189 ◽  
pp. 265-269 ◽  
Author(s):  
Qiu Feng Li ◽  
Pang Huang ◽  
Yin Liao
Keyword(s):  
Linear Array ◽  
Imaging Technique ◽  
Structural Characteristics ◽  
Concrete Structures ◽  
Imaging Method ◽  
Geometrical Relation ◽  
Scan Data ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique ◽  
Detecting Method

Because of the need of rapid detection of internal defects and embedded object in concrete structures, a detecting method with linear array probes is presented here, which is the high-resolution and efficient imaging technique for concrete structures by combining with synthetic aperture focusing technique (SAFT). Firstly, array simulation data are processed to be amalgamated B-scan data of concrete structures according to the structural characteristics of linear array; And then the B-scan data are reconstructed in the light of geometrical relation of ultrasonic path and SAFT; At last, the structural imaging figure are calculated. It can be shown from simulation results that the method is effective, and the embedded object in model can be identified effectively.

scholarly journals Time-Domain Topological Energy Imaging Method of Concrete Cavity Defect by Lamb Wave

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Wen-Fa Zhu ◽  
Wei Shao ◽  
Le-Le Peng ◽  
Guo-Peng Fan ◽  
Xing-Jie Chen ◽  
...  
Keyword(s):  
Time Domain ◽  
Lamb Wave ◽  
Wave Dispersion ◽  
Imaging Method ◽  
Sound Fields ◽  
Wave Imaging ◽  
Reference Medium ◽  
Synthetic Aperture Focusing ◽  
Synthetic Aperture Focusing Technique ◽  
Defect Imaging

This paper presents an ultrasonic Lamb wave imaging method based on time-domain topological energy to address artifacts in the results of traditional ultrasound imaging methods. This method is based on topological theory and the calculation of the direct and adjoint sound fields in a defect-free reference medium. It focuses the direct and adjoint sound fields at the cavity defect using time reversal and their time-domain topological energy as the pixel values of the image to reduce the artifacts. The physical mechanism of time-domain topological energy (TDTE) imaging is revealed by finite element simulation and experiment. The feasibility of this method for multilayer concrete cavity defect imaging is verified. Compared with the traditional synthetic aperture focusing technique (SAFT) imaging method, the numerical simulation and experimental results show that the method can overcome the influence of ultrasonic Lamb wave dispersion and locate cavity defects with high accuracy and few artifacts. These features indicate the potential of the method in imaging damage concrete structures.

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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