Spatially Adaptive Thresholding of the Empirical Mode Decomposition for Speckle Reduction Purposes

Inhalt:
Automatic interpretation of SAR data, especially in coastal images, is extremely difficult due to speckle noise and its inherent multiplicative nature. In this paper, a speckle reduction filtering technique based on Empirical Mode Decomposition (EMD) is considered. An adaptive thresholding robust against the type of clutter is proposed against a universal fixed thresholding. The new threshold is calculated with a sliding window to preserve edge information discarding the noise. Results show a satisfactory despeckling avoiding an over-smoothing in the whole image. After an analysis of the adaptive threshold levels, a ship detector is designed as an added value.