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Polarity change extraction of GPR data for under-road cavity detection; application on Sudeoksa testbed data

Abstract

Ground penetrating radar (GPR) is one of the most widely used geophysical survey methods to locate cavities under roads due to its speedy exploration and high-resolution imaging. To locate underground cavities using GPR, we need to distinguish between cavity-induced reflections and other reflections, which can be achieved by examining the polarity change in reflections compared to the polarity of the transmitted signal. The polarity change can be measured from the phase shift between the target and first reflections. To estimate the phase shift in reflections, the method of computing the power spectrum difference between the original trace and background signal was proposed, but the method has a limitation for shallow reflectors. As an alternative method to avoid this limitation, we propose using only one component of the power spectrum difference, the cross-correlation between the target reflection and background signal. The cross-correlation has its maximum peak at a time lag between the target and first reflection (from the air-ground interface). Additionally, the phase at that time lag represents a phase shift between the two reflections. We compare our cross-correlation-based method with the conventional method of computing the whole power spectrum difference and investigate the feasibility of our method for distinguishing cavity-induced reflections using a 2D field data set acquired in a testbed in Sudeoksa, Korea.


ISSN: 1083-1363
EISSN: 1943-2658
Serial Title: Journal of Environmental & Engineering Geophysics
Serial Volume: 24
Serial Issue: 3
Title: Polarity change extraction of GPR data for under-road cavity detection; application on Sudeoksa testbed data
Affiliation: Seoul National University, Department of Energy Systems Engineering, Seoul, South Korea
Pages: 419-431
Published: 20190919
Text Language: English
Publisher: Environmental and Engineering Geophysical Society, Englewood, CO, United States
References: 38
Accession Number: 2019-095095
Categories: Engineering geologyApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables, sects.
N33°00'00" - N43°00'00", E124°15'00" - E130°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Abstract, copyright, Environmental & Engineering Geophysical Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201923
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