Interpretation of Ground Penetrating Radar Image Using Digital Wavelet Transform

2012 ◽  
Vol 5 (3) ◽  
pp. 174-182 ◽  
Author(s):  
Bello Y. Idi ◽  
Md. N. Kamarudin
Keyword(s):  
Wavelet Transform ◽  
Ground Penetrating Radar ◽  
Radar Image ◽  
Ground Penetrating

scholarly journals Study on Wavelet Entropy for Airport Pavement Inspection using a Multi-Static GPR System

Geophysics ◽  
2021 ◽  
pp. 1-74
Author(s):  
Lilong Zou ◽  
Kazutaka Kikuta ◽  
Amir M. Alani ◽  
Motoyuki Sato
Keyword(s):  
Wavelet Transform ◽  
Ground Penetrating Radar ◽  
Large Area ◽  
New Approach ◽  
Wavelet Entropy ◽  
High Entropy ◽  
Airport Pavement ◽  
Base Experiment ◽  
Pavement Structures ◽  
Ground Penetrating

The multi-layer nature of airport pavement structures is susceptible to the generation of voids at the bonding parts of the structure, which is also called interlayer debonding. Observations have shown that the thickness of the resulting voids is usually at the scale of millimeters, which makes it difficult to inspect. The efficient and accurate characteristics of ground penetrating radar (GPR) make it suitable for large area inspections of airport pavement. In this study, a multi-static GPR system was used to inspect the interlayer debonding of a large area of an airport pavement. A special antenna arrangement can obtain common mid-point (CMP) gathers during a common offset survey. The presence of interlayer debonding affects the phase of the reflection signals, and the phase disturbance can be quantified by wavelet transform. Therefore, an advanced approach that uses the average entropy of the wavelet transform parameters in CMP gathers to detect the interlayer debonding of airport pavement is proposed. The results demonstrate that the regions with high entropy correspond to the regions where tiny voids exist. The new approach introduced in this study was then evaluated by a field-base experiment at an airport taxiway model. The results show that the proposed approach can detect interlayer debonding of the pavement model accurately and efficiently. The on-site coring results confirm the performance of the proposed approach.

scholarly journals Application of Ground Penetrating Radar in Detecting Deeply Embedded Reinforcing Bars in Pile Foundation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Daochuan Zhou ◽  
Haitang Zhu
Keyword(s):  
Ground Penetrating Radar ◽  
Pile Foundation ◽  
Field Testing ◽  
Radar Image ◽  
Reinforcing Bars ◽  
Raw Data ◽  
Centre Frequency ◽  
Wave Interference ◽  
Concrete Pile ◽  
Ground Penetrating

Ground penetrating radar (GPR) has been widely used for nondestructive testings in civil engineering. However, the GPR has not been adequately applied in detecting deeply embedded reinforcing bars, which is usually difficult to be revealed in radar image due to the wave interference and attenuation in large depth penetration. This study presents a new approach for the GPR detection of deeply embedded reinforcing bars in the reinforced concrete pile foundation. The aim of the GPR survey is to determine the existence and the depth of internal reinforcing bars in the pile foundation for solving engineering dispute. Low centre frequency antenna was used in GPR field testing to obtain the reflected raw data. Optimized procedures of digital filtering techniques were applied to process the GPR raw data. The deeply embedded reinforcing bars are revealed in the radar image after the field testing and postprocessing procedures. The depth of the reinforcing bars was estimated based on the hyperbola match method. The GPR test results were validated by the excavation of the pile foundation. The low centre frequency antenna has been found to be essential to obtain the reflected wave signals of deeply embedded reinforcing bars. The optimized processing procedures is useful to identify and display the reinforcing bars in radar image. The combination of low centre frequency antenna and the postprocessing procedures make the detection of deeply embedded reinforcing bars feasible. The proposed GPR testing method has been found to be effective to estimate the depth of deeply embedded reinforcing bars, which provides the key information for solving engineering dispute.

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