Discussion on the Origin of the Strength of Phasor Quaternion Self-Organizing Map

Previously we proposed a ground penetrating radar (GPR) system employing the phasor quaternion self-organizing map (PQSOM) to deal with phasor quaternion (PQ) feature vectors extracted from scattering matrices. It performs un-supervised grouping to achieve visualization. Compared with conventional complex-valued self-organizing maps (CSOM) and quaternion self-organizing map (QSOM), PQSOM has better grouping performance. In this paper, we investigate the origin of the strength of PQSOM. We discuss the advantages of using PQ vectors as feature vectors from a extracted data perspective, and then analyze how update rules of PQSOM effectively use PQ vectors to achieve better visualization. Our analysis is verified by the experimental results.