Efficient multiple layer boundary detection in ground-penetrating radar data using an extended Viterbi algorithm

In landmine detection using vehicle-mounted ground-penetrating radar (GPR) systems, ground tracking has proven to be an effective pre-processing step. Identifying the ground can aid in the correction of distortions in downtrack radar data, which can result in the reduction of false alarms due to ground anomalies. However, the air-ground interface is not the only layer boundary detectable by GPR systems. Multiple layers can exist within the ground, and these layers are of particular importance because they give rise to anomalous signatures below the ground surface, where target signatures will typically reside. In this paper, an efficient method is proposed for performing multiple ground layer-identification in GPR data. The method is an extension of the dynamic programming-based Viterbi algorithm, finding not only the globally optimal path, which can be associated with the ground surface, but also locally optimal paths that can be associated with distinct layer boundaries within the ground. In contrast with the Viterbi algorithm, this extended method is uniquely suited to detecting not only multiple layers that span the entire antenna array, but also layers that span only a subset of the channels of the array. Furthermore, it is able to accomplish this while retaining the efficient nature of the original Viterbi scheme.