Image smoothing in the spatial domain using multigrid conjugate gradient methods based on accelerated iterative shrinkage
Kasauka Dabwitso, Hiroshi Tsutsui, Imai Seijiro, Takashi Imagawa, Hiroyuki Okuhata, Yoshikazu Miyanaga · 2016
Recently, edge preserving image smoothing techniques have been developed based on fast Fourier transformation (FFT) methods. In this paper, we present an alternative implementation for an existing image smoothing algorithm using a spatial iterative method, multigrid conjugate gradient (MGCG). In the case of FFT solvers, so-called wraparound error occurs in the image boundary due to the periodicity implied by the discrete Fourier transformation. Since the proposed method utilizes iterative methods in the spatial domain, wraparound error free image smoothing can be archived. Experimental results shows that the proposed method provides superior results compared to an FFT solver in terms of computational cost and smoothing quality.