However, SAR data are subject to speckle, a multiplicative random noise that
considerably reduces the interpretability of the images and limits classification techniques,
and SAR images have to be filtered in order to increase the signal-to-noise ratio. (Brivio et. al.
2002) For this purpose, various filters such as Mean, Median, Frost, Lee and Gamma-Map
were tested with different window sizes and over two passes on the data set. The selected
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filtering was done using a 3*3 median filter first, and then the second iteration using a 5*5
mean filter.