Refined denoising method for SAR image in the complex wavelet domains

Addressing SAR image speckle denoising, this dissertation proposes a new method based on dual tree complex wavelet transformation combined with modification to them according to significant coefficient rule. In the method, a thresholding method are adapted for each selected subband based on the nonlinear functions. The nonlinear functions are based on sigmoid functions. And then, the wavelet coefficients are modified according to a rule whether the coefficient is a significant one or not. Experimental results show that our algorithm is among the best for speckle removal.