The Application of KL Transform to Remove Direct Wave in Ground Penetrating Radar Records

2007 ◽  
Author(s):  
Huo Zhihua ◽  
Wang Minghui
Keyword(s):  
Ground Penetrating Radar ◽  
Direct Wave ◽  
Ground Penetrating

Measurement of Bulk Electrical Properties Using GPR with a Variable Reflector

2018 ◽  
Vol 23 (4) ◽  
pp. 489-496
Author(s):  
J. David Redman ◽  
A. Peter Annan ◽  
Nectaria Diamanti
Keyword(s):  
Electrical Properties ◽  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Arrival Time ◽  
Wood Chip ◽  
Direct Wave ◽  
Trace Data ◽  
Ground Penetrating ◽  
Prototype Instrument

Bulk electrical properties of media are important inherently for ground penetrating radar (GPR) applications and for providing a means to determine indirectly other physical properties such as moisture content. We have developed a reflector whose reflectivity can be controlled electronically. This variable reflector controlled by a GPR provides an effective method to measure bulk electrical properties of media. For sample measurements, the GPR is placed on one side of a sample and the variable reflector on the opposite side. GPR trace data are then acquired with the reflector in an on-state and in the off-state. By differencing these measurements, we improve the ability to detect the specific reflection event from the variable reflector. This process removes both the direct wave and clutter from the trace data, improving the quality of the refection event and our ability to accurately pick its arrival time and amplitude. We describe the variable reflector, a prototype instrument based on the reflector and numerical modeling performed to understand its response. We also show the results of testing applications to the measurement of wood chip moisture content and monitoring of the electrical properties of concrete during the curing process.

scholarly journals Non-destructive evaluation of moisture content in wood by using Ground Penetrating Radar

2016 ◽  
Author(s):  
Hamza Reci ◽  
Tien Chinh Maï ◽  
Zoubir Mehdi Sbartaï ◽  
Lara Pajewski ◽  
Emanuela Kiri
Keyword(s):  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Wood Fiber ◽  
Fiber Direction ◽  
Direct Wave ◽  
Reflected Waves ◽  
Moisture Variation ◽  
Reflection Configuration ◽  
Ground Penetrating ◽  
Non Destructive

Abstract. This paper presents the results of a series of laboratory measurements carried out to study how the Ground Penetrating Radar (GPR) signal is affected by moisture variation in wood material. The effects of the wood fiber direction, with respect to the polarisation of the electromagnetic field, are investigated. The relative permittivity of wood and the amplitude of the electric field received by the radar are measured for different humidity levels, by using the direct-wave method in Wide Angle Radar Reflection configuration, where one GPR antenna is moved while the other is kept in a fixed position. The received signal is recorded for different separations between transmitting and receiving antennas. Direct waves are compared to reflected waves: it is observed that they show a different behaviour when the moisture content varies, due to their different propagation paths.

scholarly journals Monitoring infiltration processes with high-resolution surface-based Ground-Penetrating Radar

2015 ◽  
Vol 12 (11) ◽  
pp. 12215-12246 ◽  
Author(s):  
P. Klenk ◽  
S. Jaumann ◽  
K. Roth
Keyword(s):  
High Resolution ◽  
Water Content ◽  
Ground Penetrating Radar ◽  
Relaxation Processes ◽  
Dual Frequency ◽  
Relative Precision ◽  
Direct Wave ◽  
Wave Travel ◽  
Ground Penetrating ◽  
Better Than

Abstract. In this study, we present a series of high resolution Ground-Penetrating Radar (GPR) measurements monitoring two artificially induced infiltration pulses into two different sands with dual-frequency ground-based GPR. After the application of the second infiltration pulse, the water table in the subsoil was raised by pumping in water from below. The longterm relaxation of the system was then monitored over the course of several weeks. We focused on the capillary fringe reflection and on observed variations in soil water content as derived from direct wave travel times. We discuss the advantages of this dual-frequency approach and show the attainable precision in longterm monitoring of such relaxation processes. Reaching a relative precision of better than 0.001 [–] in water content, we can clearly discern the relaxation of the two investigated sands.

scholarly journals Non-destructive evaluation of moisture content in wood using ground-penetrating radar

2016 ◽  
Vol 5 (2) ◽  
pp. 575-581 ◽  
Author(s):  
Hamza Reci ◽  
Tien Chinh Maï ◽  
Zoubir Mehdi Sbartaï ◽  
Lara Pajewski ◽  
Emanuela Kiri
Keyword(s):  
Moisture Content ◽  
Ground Penetrating Radar ◽  
Dielectric Constants ◽  
Fibre Direction ◽  
Direct Wave ◽  
Reflected Waves ◽  
Moisture Variation ◽  
Reflection Configuration ◽  
Ground Penetrating ◽  
Non Destructive

Abstract. This paper presents the results of a series of laboratory measurements, carried out to study how the ground-penetrating radar (GPR) signal is affected by moisture variation in wood material. The effects of the wood fibre direction, with respect to the polarisation of the electromagnetic field, are investigated. The relative permittivity of wood and the amplitude of the electric field received by the radar are measured for different humidity levels using the direct-wave method in wide angle radar reflection configuration, in which one GPR antenna is moved while the other is kept in a fixed position. The received signal is recorded for different separations between the transmitting and receiving antennas. Dielectric constants estimated from direct waves are compared to those estimated from reflected waves: direct and reflected waves show different behaviour when the moisture content varies, due to their different propagation paths.

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

Deteksi Bentuk Objek Bawah Tanah Menggunakan Pengolahan Citra B-Scan pada Ground Penetrating Radar (GPR)

2017 ◽  
Vol 3 (1) ◽  
pp. 73-83
Author(s):  
Rahmayati Alindra ◽  
Heroe Wijanto ◽  
Koredianto Usman
Keyword(s):  
Signal Processing ◽  
Ground Penetrating Radar ◽  
Post Processing ◽  
Data Survey ◽  
Ground Penetrating

Ground Penetrating Radar (GPR) adalah salah satu jenis radar yang digunakan untuk menyelidiki kondisi di bawah permukaan tanah tanpa harus menggali dan merusak tanah. Sistem GPR terdiri atas pengirim (transmitter), yaitu antena yang terhubung ke generator sinyal dan bagian penerima (receiver), yaitu antena yang terhubung ke LNA dan ADC yang kemudian terhubung ke unit pengolahan data hasil survey serta display sebagai tampilan output-nya dan post  processing untuk alat bantu mendapatkan informasi mengenai suatu objek. GPR bekerja dengan cara memancarkan gelombang elektromagnetik ke dalam tanah dan menerima sinyal yang dipantulkan oleh objek-objek di bawah permukaan tanah. Sinyal yang diterima kemudian diolah pada bagian signal processing dengan tujuan untuk menghasilkan gambaran kondisi di bawah permukaan tanah yang dapat dengan mudah dibaca dan diinterpretasikan oleh user. Signal processing sendiri terdiri dari beberapa tahap yaitu A-Scan yang meliputi perbaikan sinyal dan pendektesian objek satu dimensi, B-Scan untuk pemrosesan data dua dimensi  dan C-Scan untuk pemrosesan data tiga dimensi. Metode yang digunakan pada pemrosesan B-Scan salah satunya adalah dengan  teknik pemrosesan citra. Dengan pemrosesan citra, data survey B-scan diolah untuk didapatkan informasi mengenai objek. Pada penelitian ini, diterapkan teori gradien garis pada pemrosesan citra B-scan untuk menentukan bentuk dua dimensi dari objek bawah tanah yaitu persegi, segitiga atau lingkaran. 

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