The invention is related to spatial diffusion in images. Spatial diffusion helps blurring small discontinuities. Edges become sharper by spatial diffusion as well.A method for generating a spatial diffused image from an input image is described wherein the method comprises applying on the input image an inverted Gaussian spatial bilateral filter with a spatial weight which takes the form of an inverted Gaussian.The inverted-Gaussian-spatial bilateral filter, which uses an inverted-Gaussian function as the kernel of spatial filter, can remove small spots in large smooth areas efficiently.