二维相位解缠绕处理是干涉合成孔径雷达(Interferometric synthetic aperture radar,InSAR)数据处理的关键。本文提出了一种基于等效残差点的InSAR相位解缠绕算法。该算法首先提出了等效残差点的概念,利用质量图与残差点分布之间的关系,将残差点密集的低质量相位区域视为等效残差点,然后采用不同方法分别对高质量相位区域和等效残差点的内部区域进行相位解缠绕。本文算法基于等效残差点正确的设置枝切线,可以阻止由于积分路径穿过残差点密集的低质量相位区域所引起的展开相位跳变现象,利用多像素单元共同估计的方法对残差点的内部区域进行相位展开,突破了对于干涉相位梯度值的限制,并且可以有效阻止相位解缠绕误差由低质量相位区域向高质量相位区域的传递。实验结果证明,本文方法可以获得比其他算法更好的相位解缠绕结果。
A two-dimensional phase unwrapping approach using equivalent residues is proposed for interferometric synthetic aperture radar (InSAR). In the proposed approach, the relationship between quality map and residues is used to find out the low quality unreliable regions, which are residues dense distribution and regarded as equivalent residues. Then, different phase unwrapping strategies are applied to different quality regions. With this methodology, integration path crossing of unreliable regions, which may produce a phase error propagating to all the pixels in integration path, is prevented because that the unreliable regions are treated as equivalent residues. Each pixel inside equivalent residue is unwrapped based on its unwrapped neighbors, which allows the absolute value of phase gradient between two adjacent pixels larger than π. Simulated and real SAR data validate the new approach.