GPR technologies

[GP-01] Comparing two interpolation methods based on POCS for determining EM wave velocity from sparse CMP data

*Koki Oikawa¹, Hirotaka Saito¹, Seiichiro Kuroda², Kazunori Takahashi³ (1. Tokyo University of Agriculture and Technology (Japan), 2. National Agriculture and Food Research Organization (Japan), 3. OYO Corporation (Japan))

As an array antenna ground penetrating radar (GPR) system electronically switches any antenna combinations sequentially in milliseconds, multi-offset gather data, such as common mid-point (CMP) data, can be acquired almost seamlessly. The array GPR system has been used to collect time-lapse multi-offset GPR data, such as CMP data, during the field infiltration experiment (Iwasaki et al., 2016). However, the CMP data obtained by the array GPR may be too sparse to estimate reliable EM velocity using a standard velocity analysis, such as semblance. We then attempted to interpolate the sparse CMP data by projection onto convex sets (POCS) algorithm (Yi et al., 2016) and this method coupled with NMO correction to determine EM wave velocities.

The main objective of this study was to compare two interpolation methods based on POCS to determine EM wave velocities from sparse CMP data collected with the array GPR. Specifically, the effect of applying NMO correction prior to interpolation was investigated. The two methods were applied to the sparse CMP data collected during the field infiltration test with the array GPR. The results show that the NMO correction prior to the interpolation may improve the accuracy of the final velocity estimation.