scholarly journals Crack detection in lossy two-dimensional structures by means of a microwave imaging approach

2000 ◽  
Vol 11 (4) ◽  
pp. 233-244 ◽  
Author(s):  
Salvatore Caorsi ◽  
Andrea Massa ◽  
Matteo Pastorino ◽  
Fabio Righini
Keyword(s):  
Crack Detection ◽  
Microwave Imaging ◽  
Two Dimensional ◽  
Imaging Approach

Detection of Non-Metallic Cords Using Synthetic Aperture Acoustic Imaging

2012 ◽  
Author(s):  
John A. Judge ◽  
Joseph F. Vignola ◽  
Aldo A. J. Glean ◽  
Teresa J. Ryan ◽  
Chelsea E. Good ◽  
...  
Keyword(s):  
Ambient Noise ◽  
Ground Surface ◽  
Acoustic Imaging ◽  
Acoustic Energy ◽  
Synthetic Aperture ◽  
Two Dimensional ◽  
Two Dimensional Image ◽  
Imaging Approach ◽  
Different Diameters ◽  
Made In

Synthetic aperture acoustic (SAA) imaging is a technique for remotely obtaining information about the location, geometry, and mechanical properties of objects based on the way they scatter incident acoustic energy. Results are presented for an experimental investigation of the use of SAA imaging to detect non-metallic cords of different sizes laid in various configurations on the ground surface in an outdoor urban environment. Interest in this application of SAA stems from the fact that non-metallic cords are not readily detectable with synthetic aperture radar (SAR) and that the SAA imaging approach represents a relatively inexpensive alternative or supplement to SAR. The measurement system is comprised of a mobile acoustic transceiver (a speaker and microphone) that broadcasts a burst chirp with a bandwidth of 2–15 kHz. The recorded signal is used to form a two-dimensional image of the distribution of acoustic scatterers within the scene. For this study, five different diameters (2–15mm) of nylon cord laid on the ground were imaged in different configurations. These measurements were made in the presence of urban ambient noise of varying levels. The goal of this study was to identify the effect of environmental noise and other parameters on detectability. The results demonstrate that non-metallic cords can be detected acoustically if the angle to the transceiver path is sufficiently small.

scholarly journals Detection of Cracks in Concrete Structure Using Microwave Imaging Technique

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
E. A. Jiya ◽  
N. S. N. Anwar ◽  
M. Z. Abdullah
Keyword(s):  
Crack Detection ◽  
Imaging Technique ◽  
Reconstruction Algorithm ◽  
Microwave Imaging ◽  
Structural Failure ◽  
Manual Inspection ◽  
Vibration Technique ◽  
Small Cracks ◽  
Evaluation Techniques ◽  
Nondestructive Evaluation Techniques

Cracks in concrete or cement based materials present a great threat to any civil structures; they are very dangerous and have caused a lot of destruction and damage. Even small cracks that look insignificant can grow and may eventually lead to severe structural failure. Besides manual inspection that is ineffective and time-consuming, several nondestructive evaluation techniques have been used for crack detection such as ultrasonic technique, vibration technique, and strain-based technique; however, some of the sensors used are either too large in size or limited in resolution. A high resolution microwave imaging technique with ultrawideband signal for crack detection in concrete structures is proposed. A combination of the delay-and-sum beamformer with full-view mounted antennas constitutes the image reconstruction algorithm. Various anomaly scenarios in cement bricks were simulated using FDTD, constructed, and measured in the lab. The reconstructed images showed a high similarity between the simulation and the experiment with a resolution of λ/14 which enables a detection of cracks as small as 5 mm in size.

A novel technique for reducing the imaging domain in microwave imaging of two dimensional circularly symmetric scatterers

2005 ◽  
Vol 44 (5) ◽  
pp. 423-427 ◽  
Author(s):  
Vinu Thomas ◽  
C. Gopakumar ◽  
A. V. Praveen Kumar ◽  
V. Hamsakutty ◽  
Anil Lonappan ◽  
...  
Keyword(s):  
Microwave Imaging ◽  
Two Dimensional ◽  
Novel Technique
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