“…Speckle noise is a random process and can be modeled using gamma, Rayleigh, and Fisher-Tippett distribution [ 25 – 27 ]. In our work, the simplified speckle noise model has been employed, since it has been applied successfully in many studies [ 11 , 24 , 28 , 29 ]. where u ( x ), v ( x ), and n ( x ) denote the observed signal, original unknown signal, and zero-mean Gaussian noise, respectively.…”