Salim Bettahar Amine Boudghene Stambouli Shock filter coupled to curvature diffusion for image denoising and sharpening. 1481-1489 2008 26 Image Vision Comput. 11 http://dx.doi.org/10.1016/j.imavis.2008.02.010 db/journals/ivc/ivc26.html#BettaharS08