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Abstract This paper presents some experimental results on the properties of image speckle along with two adaptive filters that are useful for speckle reduction. An investigation of available SIR-B digital image data over Australia shows that speckle is non-while Gaussian noise and fits a multiplicative noise model in which the noise, uncorrelated with signal, has a mean of 1 and a constant standard deviation. The non-uniform spectrum can be represented by an empirical formula. Based on these results, two adaptive filters have been designed, a moving average filter and a combined moving median filter. In both of these, variance ratios are used to govern the filter parameters. The filters have been applied to some SIR-B image segments, showing good results in both smoothing speckle and maintaining edges.
Changle Li (Fri,) studied this question.