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Reflection Polarity Estimation of GPR Data for Under-Road Cavity Detection
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 25th European Meeting of Environmental and Engineering Geophysics, Sep 2019, Volume 2019, p.1 - 5
Abstract
When we locate subsurface cavities using the ground penetrating radar (GPR) method, the estimation of reflection polarity is required to distinguish cavity-induced reflections from the other reflections. In general, we investigate the polarity of reflections through the visual inspection of GPR profile. However, reflections are often overlapped with other reflections and noise, which makes this visual inspection unreliable. As a method to quantitatively estimate the reflection polarity, the power spectrum difference method was proposed, but it sometimes fails to estimate the polarity of reflections for shallow reflectors. In this study, we analyze this limitation of the conventional polarity estimation method and propose a modified approach that can reliably estimate the polarity of reflections even for shallow reflectors. Through the synthetic and field examples, we demonstrate that our approach effectively estimates the polarity of reflections, which eventually enables us to select potential cavity-induced reflections among many reflections on GPR profile.