Detection and recognition of dim and small targets in sea clutter background based on polarization decomposition.

The consideration of the polarization scattering characteristics of radar echo in the detection of small and dim targets in a sea clutter background leads to high detection probability and high recognition accuracy. In this study, a target detection method based on canonical polar decomposition (CPD) was developed. In particular, a polarization matrix T was constructed for the radar echo of each range bin; the absolute value A and phase theta of T were extracted; the diagonal elements of the characteristic matrix H were extracted and converted into the singular spectrum form; and the negative entropies E-A and E-theta of the singular spectrum were calculated. We set E = E(A)e(jE theta); then, the negative entropy value E of each range bin was obtained, and the range bin of the minimum value was identified, which was the target position. Thereafter, a seven-component scattering power decomposition (7SD) was performed on T. The basic scattering structure of the target was analyzed, and a polar feature description word (PFDW) was formed to recognize the target characteristics. The effectiveness of the proposed method was verified by using the sea clutter dataset obtained with the IPIX radar. The comparison with the statistical model-based method is also made for indicating the advantage of the proposed method.