Extraction of Anisotropic Characteristics of Scattering Centers and Feature Enhancement in Wide-Angle SAR Imagery Based on the Iterative Re-Weighted Tikhonov Regularization

The anisotropic characteristic reflects discriminating features of the geometry of a scattering center. In this study, we propose a novel method based on the iterative re-weighted Tikhonov regularization (IRWTR) to achieve the extraction of anisotropic characteristics of scattering centers in the wide-angle SAR synthetic aperture radar (SAR) imaging. Moreover, based on the extracted anisotropic scattering behaviors, the incomplete imaging results of the distributed scattering centers are restored. In this paper, we first discussed the scattering property in SAR imagery from the perspective of attributed scattering center model (ASCM). The reason for the incomplete imaging results of the distributed scattering centers was also discussed based on the ASCM. Subsequently, we modeled the aspect-dependent amplitude responses of a scattering center as a linear combination of a set of orthogonal basis. Consequently, the extraction of anisotropic characteristics can be transformed into an inverse problem, which was solved by the proposed IRWTR with high efficiency and accuracy. After the extraction, we attempted to restore the complete image of a distributed scattering center, which consisted of only two points. The enhanced SAR image can reveal the actual shape of a target. Processing results of electromagnetic computation data validated that the proposed method is effective and efficient.