A Four-component Polarimetric Decomposition Method Based on Generalized Scattering Models

Polarimetric target decomposition is a powerful tool for polarimetric synthetic aperture radar (PolSAR) data interpretation and utilization. Although many advances have been reported, scattering mechanism ambiguity still occurs for manmade targets with large orientations. Recently, a general model-based decomposition has been established to mitigate this ambiguity by modeling the orientations of manmade structures. However, the optimal solutions are obtained with nonlinear optimization which usually costs a large computation time. This work aims at maintaining the generalized scattering models while significantly reducing the computation burden. The main contributions are two-fold. Firstly, the generalized scattering models are adapted to fit the actual observed situation. The second contribution is the parameter inversion. In proposed decomposition procedure, the volume scattering power is derived through an eigen decomposition problem. Then, the helix scattering power is obtained through the imaginary part of a coherency matrix element. The next two scattering components of odd-bounce and double-bounce are calculated through a set of linear equations. As a result of extra freedoms, the roll-invariant feature, Alpha angle from H/alpha/A decomposition is selected as a branch condition to discriminate between dominant odd-bounce and double bounce scattering mechanisms. The comparison experiments are carried out on airborne PolSAR data sets. The experiment results demonstrate that the proposed method achieved improved decomposition performance and greatly reduced computation time.