INSAR干涉图的零中频矢量滤波算法

The Zero Intermediate Frequency Vector Filtering for Interferograms

提出一合成孔径雷达干涉测量干涉图的滤波方法。该方法引入无线电技术中的零中频技术,将干涉图由高的中心频率变为零中频信号,再将信号分解至矢量空间中的两路正交信号,得到正弦支路信号和余弦支路信号,并分别进行低通滤波处理,最后根据滤波后的两路正交信号计算出滤波后的零中频干涉图,并恢复干涉图的原始频率,得到原始干涉图的滤波结果。实验结果表明:该方法滤波效果较好,能够解决干涉图条纹密集时滤波处理困难、效果较差的问题。

A new filtering algorithm for interferogram wan presented. It assimilates the idea of zero intermediate frequency（ZIF）in radio technique. First, the raw interferogram is transformed to ZIF one and then decomposed to two cross signals in vector, which include the sinc signal and the cosine one. Secondly, the sine signal and the cosine one are filtered by Low-Pass （LP） filter respeetively. The LP filter can be mean fiher or median filter. This paper adopts mean filter. Then, the filtered ZI F interterogram is calculated from the filtered sine and cosine signals. Finally, it is transformed to original frequency to get the filtered result of the raw interfcrogram. Experiments show that the new interferogram filtering algorithm can resolve the difficuhy in dealing with dense fringe. The effect of this method is excellent.