Reciprocal pointer chains for identifying layer boundaries in ground-penetrating radar data

Identifying the ground surface in ground-penetrating radar (GPR) data is useful and can be done efficiently and accurately using the Viterbi algorithm. This involves representing the radar image as a trellis graph and solving for the optimal path. To identify multiple layer boundaries in a radar image in this manner, it is necessary to find multiple disjoint paths through the trellis. Two main types of algorithms currently exist that find the k best disjoint paths whose aggregate sum is minimized. However, this criterion has drawbacks. Instead, we propose a novel criterion for choosing multiple disjoint paths in a trellis that we call the reciprocal pointer chain. This criterion has both a nice intuitive and theoretical justification, and leads to an algorithm with better qualitative results and significantly lower computational complexity than any of the methods previously proposed.