一种有效的机载双频干涉地形高程重建方法

An Effective Method of Airborne Dual-frequency Interferometric Terrain Elevation Reconstruction

双频联合解缠不需要满足Iton假设,因此双频干涉可以有效地提取地形起伏较大区域的高程信息。针对目前双频干涉处理中高程重建精度低的问题,该文提出了一种有效的双频干涉SAR地形高程重建方法。该方法对常规处理流程中的关键步骤进行了改进,首先在不同波段配准之前采用非局部参数估计(NL-InSAR)技术对幅度图、相干系数、干涉相位进行精确估计,利用各个波段滤波后的幅度信息来实现不同波段的干涉相位的配准。然后采用聚类分析技术对联合解缠相位标记有效点和噪点,并利用这些有效点对联合解缠相位进行均值滤波。用于实验的机载实测数据包括同一场景的C波段和X波段主、辅SAR图像复数据,在针对实测数据处理中,该方法取得了较好的高程重建结果。

Dual-frequency joint phase unwrapping does not need to satisfy the Iton hypothesis, so dual- frequency interferometry can effectively extract elevation information from large terrain undulation areas. This paper presents an effective method for Dual-Frequency Interferometry （DFI） SAR terrain elevation reconstruction, aiming at the low precision of elevation reconstruction in DFI processing. This method improves the key steps in the conventional process. Firstly, Nonlocal Interferogram Estimation （NL-InSAR） technique is used to accurately estimate amplitude map, coherence coefficient, and Interferometric phase before the registration in different bands. After filtering, the filtered amplitude information of each band is used to realize the registration of Interferometric phase in different bands. Then clustering analysis technique is used to mark the effective points and noise points of unwrapping phase, and these effective points are used to filter the mean value of joint phase unwrapping. The airborne measured data used in the experiment include the complex data of C band and X band main and auxiliary SAR images of the same scene. In view of the measured data processing, the proposed method provides better results of elevation reconstruction.