Synthetic and field examples of ground-penetrating radar (GPR) profile improvement using two-phase detection techniques

摘要

Our results show that the primary advantages of IPHWT are a relative insensitivity to noise, if compared with conventional IPHHT, and good performance regardless of amplitude of the input signal. Such characteristics make the WT technique robust and appealing for analyzing weak transients in GPR records. Differences between IPHHT and IPHWT increase with two-way time. This is probably because of the clutter amplification produced by HT methods. The IPHWT record shows a progressive enhancement of S/N ratio as two-way time increases and could therefore be used to detect the response from deep or weak EM impedance contrasts instead of the original radargrams. The IPHWT record provides superior vertical resolution and can be used to produce the input to automatic tracking algorithms, of interest in industrial applications such as highway pavements evaluation. In synthesis, instantaneous parameters and, in particular, instantaneous phase are independent of the amplitude of the GPR signal and can be effectively exploited to detect weak transients in the radar trace, corresponding to deep interfaces or weak scatterers. Both HT and WT techniques succeed in the enhanced representation of weak transients. The latter shows superior performance when the S/N ratio is low, which demonstrates a substantial insensitivity of WT to random noise.