校正法拉第旋转影响的极化SAR图像定标算法

Calibration Algorithm of Polarimetric SAR Images Subject to Faraday Rotation

提出了一种改进的极化定标算法,应用于受法拉第旋转影响的极化SAR图像定标。假设系统具有良好的极化隔离度,即极化通道间串扰可忽略,将三角反射器作为点目标定标体,利用各通道测量值与定标体的理想散射矩阵元素间的关系,依次对通道不平衡度、法拉第旋转和绝对幅度增益进行校正。给出了算法步骤,实验的数值结果和点目标的极化特征图都验证了定标算法的有效性。

A kind of improved polarimetric SAR data calibration algorithm was introduced which was used to calibrate polarimetric SAR images subject to Faraday rotation. Trihedral corner reflectors were used as point target calibrators. Based on the assumptions that the system was well-isolated, that was to say the channel crosstalk could be ignored, and channel imbalance, Faraday rotation and absolute gain could be calibrated using the relation between the measured matrix elements and the calibrator＇s scattering matrix elements. The improved algorithm was given in concrete steps. Numerical results and point targets＇ polarimetric features are used to verify the proposed calibration algorithm.