Blind estimation of interferometric SAR phase images through fuzzy matching-pursuits

Bruno Aiazzi; Luciano Alparone; Stefano Baronti; Massimo Bianchini

doi:10.1117/12.454180

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28 January 2002 Blind estimation of interferometric SAR phase images through fuzzy matching-pursuits

Bruno Aiazzi, Luciano Alparone, Stefano Baronti, Massimo Bianchini

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Proceedings Volume 4541, Image and Signal Processing for Remote Sensing VII; (2002) https://doi.org/10.1117/12.454180
Event: International Symposium on Remote Sensing, 2001, Toulouse, France

Abstract

This paper presents an original application of fuzzy logic to restoration of interferometric phase images from IFSAR, which are affected by zero-mean uncorrelated noise, whose variance depends on the underlying coherence, thus resulting in a nonstationary random process. Spatial filtering of the phase noise is recommended, either before phase unwrapping is accomplished, or simultaneously with it. In fact, phase unwrapping basically relies on a smoothness constraint of the phase field, which is severely hampered by the noise. Space-varying linear MMSE estimation is stated as a problem of matching pursuits, in which the estimator is obtained as an expansion in series of a finite number of prototype estimators, fitting the spatial features of the different statistical classes encountered, e.g., fringes, and steep slope areas. Such estimators are calculated in a fuzzy fashion through an automatic training procedure. The space-varying coefficients of the expansion are stated as degrees of fuzzy membership of a pixel to each of the estimators. Besides the fact that neither a priori knowledge on the noise variance is required, nor a particular signal model is assumed, a performance comparison on simulated noisy images highlights the advantages of the proposed approach. Results on simulated noisy versions of Lenna show a steady SNR improvement of almost 3 dB over Kuan's LLMMSE filtering, irrespective of noise model and intensity. Applications of the proposed filter to interferometric phase images demonstrate a superior ability of preserving fringes discontinuities, together with an effective smoothing performance, irrespective of local coherence characteristics.

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Bruno Aiazzi, Luciano Alparone, Stefano Baronti, and Massimo Bianchini "Blind estimation of interferometric SAR phase images through fuzzy matching-pursuits", Proc. SPIE 4541, Image and Signal Processing for Remote Sensing VII, (28 January 2002); https://doi.org/10.1117/12.454180

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