Scattering-model-based speckle filtering of polarimetric SAR data

• Published in: IEEE transactions on geoscience and remote sensing Vol. 44; no. 1; pp. 176 - 187
• Main Authors: Jong-Sen Lee, Grunes, M.R., Schuler, D.L., Pottier, E., Ferro-Famil, L.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.01.2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anisotropic magnetoresistance; Applied geophysics; Categories; Classification; Covariance matrix; Earth sciences; Earth, ocean, space; Entropy; Exact sciences and technology; Filtering; Filters; Filtration; Internal geophysics; Pixels; Polarimetric synthetic aperture radar; Polarimetric synthetic aperture radar (POLSAR); Polarization; radar polarimetry; Radar scattering; Remote sensing; Scattering; Speckle; speckle filtering; Synthetic aperture radar; algorithms; models; wave scattering; maps; anisotropy; classification; radar polarimetry; Polarimetric synthetic aperture radar (POLSAR); synthetic aperture radar; entropy; speckle filtering; filtering; Pixel
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2005.859338

A new concept in polarimetric synthetic aperture radar (POLSAR) speckle filtering that preserves the dominant scattering mechanism of each pixel is proposed in this paper. The basic principle is to select pixels of the same scattering characteristics to be included in the filtering process. To achieve this, the algorithm first applies the Freeman and Durden decomposition to separate pixels into three dominant scattering categories: surface, double bounce, and volume, and then unsupervised classification is applied. Speckle filtering is performed using the classification map as a mask. A single-look or multilook pixel centered in a 9 /spl times/ 9 window is filtered by including only pixels in the same and two neighboring classes from the same scattering category. This filter is effective in speckle reduction, while perfectly preserving strong point target signatures, and retains edges, linear, and curved features in the POLSAR data. The effect of speckle filtering on scattering characteristics, such as entropy, anisotropy, and alpha angle, will be discussed.