“…To date a variety of image denoising methods using smoothing constraint have been introduced, such as the Gaussian smoothing model [2,3], the anisotropic filtering model [4][5][6][7], the total variation (TV) model [8], the Yaroslavsky [12] neighbourhood filter, the Winner filter [13,14], the Kalman filter [15,16], and so on. Among these methods, the TV method has drawn much attention, which is widely used over the past decades, probably because of its low time consumption and well-understood behaviour.…”