Yamaguchi Decomposition Based on Hierarchical Nonnegative Eigenvalue Restriction

To solve the issue that coherency matrices of the existing Yamaguchi decompositions do not satisfy Nonnegative Eigenvalue Restriction (NER), Yamaguchi decomposition based on hierarchical NER is proposed. It is derived that the NER problem results from the overestimation of scattering powers, and it is pointed out that if the NER problem of remainder coherency matrix is resolved, the NER problems of all coherency matrices are also resolved. Then, the NER methods of the first layer to the fourth layer are proposed orderly based on NonNegative Eigenvalue Decomposition (NNED) to depress the overestimation of scattering powers. For the NER methods, the posterior-layer NER methods need to hierarchically implement the anterior-layer NER methods. The fourth-layer NER method resolves the NER problem of remainder coherency matrix, so the NER problems of all coherency matrices are also resolved. In addition, the fast NNED more efficient than the existing NNED is derived. The experiment result shows that the proposed decomposition can markedly enhance double-bounce scattering power and reduce volume scattering power for urban areas, and enhance surface scattering power for ocean areas.