Filtering method for SAR interferograms with strong noise

Abstract

We develop a filtering method for SAR interferograms with strong noise based on the concept of the Vondrák filter and the commonly used Goldstein filter. The one‐dimensional Vondrák filter is first extended to two dimensions, and then utilized to smooth the Fourier spectra of overlapped interferogram patches. The smoothed spectra are then back‐transformed into the interferogram space. Experimental results with simulated and real datasets show that the proposed filter can eliminate up to 70% of noise in a SAR interferogram. The results also show a 15% to 35% improvement over some of the existing filters when the noise in an interferogram is strong, and the stronger the noise in an interferogram, the greater is the improvement.

Acknowledgements

The work presented was partially supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region (PolyU 5064/02E) and a Postdoctoral Fellowship to the first author by the Hong Kong Polytechnic University (G‐YX48). The images are provided by the European Space Agency under a Category 1 User Project (AO‐1232). We thank Dr. Baran for providing his filtering program and for some discussions.