Coherent Scatterers in Urban Areas: Characterisation and Information Extraction

Rafael Zandona Schneider(1) , Kostantinos Papathanassiou(1) , Kostantinos Papathanassiou(1) , Irena Hajnsek(1) , Alberto Moreira(1) , and Kostantinos papathanassiou(1)

(1) DLR, Muenchner Strasse 20, 82234 - Wessling, Germany

Abstract

SAR images over urban areas are characterised by strong geometrical distortions due to the side-looking acquisition geometry of SAR systems and the stepwise height variations of the scenes. This, combined with the complexity of the scattering processes in urban scenarios makes the interpretation and information extraction from SAR images over urban areas non-trivial. To simplify interpretation and information extraction, a subset of scatterers within the scene, the so-called coherent scatterers (CSs), which are characterised by point-like scattering behaviour, have been proposed [1]. The advantage of such CSs is that they are (widely) unaffected by geometrical distortions and multiple scattering effects and allow - as far as possible - a direct interpretation [2]. In this paper, the potential of CSs is further evaluated. Orientation and Dielectric properties of individual CSs are estimated and discussed. The effect of the incident angle on the detection and information extraction from CSs is investigated. A comparison between CSs detected at X-band and L-band is performed allowing additional insights in the physical nature of CSs. For this, multi-baseline repeat pass interferometric data acquired by DLR's E-SAR system in a Quad-pol mode at L-band and a Single-pol mode at X-band over the city of Dresden in Germany are used.

[1] R. Z. Schneider, K. Papathanassiou, I. Hajnsek, and A. Moreira, Analysis of coherent scatterers over urban areas, Workshop on Applications of SAR Polarimetry and Polarimetric Interferometry (POLinSAR'2005), Frascati, Italia, 17 - 21 January 2005. Available on http://earth.esa.int/cgi-bin/confpol.pl?abstract=124

[2] R. Z. Schneider, K. Papathanassiou, I. Hajnsek, and A. Moreira, Polarimetric interferometry over urban areas: information extraction using coherent scatterers, Proceedings of Geoscience and Remote Sensing Symposium (IGARSS'05), Seoul, Corea, vol. 5, pp. 2616-2618, 25 - 29 July 2005.

 

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