A Two-Step Target Decomposition Method for Polarimetric SAR based on Reflection Symmetry

Symmetry is an important characteristic for PolSAR data. Studying the reflection symmetry of the target is conducive to simplify the study of its scattering problem. Therefore, this paper proposes a two-stage target decomposition model based on symmetry. On the first step of the decomposition process, we decompose the coherency matrix into reflection symmetric scattering component and asymmetric scattering component. During the second step of the decomposition process, the reflection symmetric scattering component is further decomposed into surface, double-bounce and volume scattering. The asymmetric scattering component is further decomposed into helix, oriented dipole, compound dipole, mixed-dipole scattering and a new scattering which we called mixed asymmetric scattering. By extracting the non-reflection symmetric scattering component, the proposed target decomposition model could be applied without the limitation of the reflection symmetry condition. The ESAR experimental data in Oberpfaffenhofen, Germany is implemented in the paper and the results improve the defect of rough scattering characteristics analysis in the traditional target decomposition methods.