SAR Image Despeckling Based on Multi-scales Adaptive Wavelet Thresholding

An improved algorithm based on wavelet thresholding is proposed for suppressing speckle noise of synthetic aperture radar image.The method uses the local statistics of multiscale wavelet coefficients to obtain estimated parameters and thresholds based on BayesShrink threshold.Moreover,it employs the method of enhanced Lee filter to smooth the homogeneous areas and preserve the point-target areas.Resultsdemonstrate that compared with the results of enhanced Lee filter,traditional soft-thresholding of discrete wavelet transform(DWT) and BayesShrink soft-thresholding,the improved algorithm provides the largest equivalent number of looks(ENL) and edge sustain index(ESI),which indicates it can not only reduce the speckle but also preserve edges and details.