基于FFT平移与相关分析的多尺度星载SAR自动配准

SAR图像配准是SAR图像应用,尤其是时间序列SAR图像应用的重要处理步骤之一。为实现重复星载SAR图像的快速、自动配准,通过将小波多尺度变换与快速傅立叶频谱变换相结合,实现了对星载SAR图像间初始偏移的快速估计,并在此基础上利用基于窗口的相关分析,实现了SAR图像的精确配准。选用星载ALOS-PALSAR和Radarsat-2影像作为试验数据,对提出的方法进行了实验分析。实验结果表明:该方法在无需任何先验知识的情况下,可以全自动完成重复轨道星载SAR数据的快速配准,且精度满足SAR干涉处理等时间序列SAR应用处理的需求,具有较强的鲁棒性。

An Auto-registration Method for Space-borne SAR Images based FFT-shift Theory and Correlation Analysis in Multi-scale Scheme

SAR co-registration is one of the crucial steps in the process of SAR images analysis,especially for multi-temporal SAR images analysis.Focusing on the characteristics of the repeat-pass space-borne SAR image,an auto-registration method for repeat-pass SAR complex image pair is proposed based on a multi-steps,which combines the Fourier transform and correlation-coefficient algorithm in multi-scale scheme.Firstly,an initial offset is estimated in Fourier domain by using the 3rd level wavelet decomposition image.Then,taking these initial offsets into account,coarse and fine registration is applied to the whole image and the oversampled image successively by correlation analysis of the images on several windows distributed randomly.ALOS-PALSAR and Radarsat-2 data are used for validation of this registration method.And the experimental results show that the proposed technique achieves the co-registration of the SAR images with the accuracy up to a fraction of a pixel automatically without a priori knowledge and this approach is efficient.