A method of segmenting a digitized image includes providing a digitized image on a domain of points on an N%N grid, defining a weight between each pair of adjacent points in the image based on the intensity difference of each said point pair, marking a subset of points in the image, associating a probability potential with each unmarked point, and using a multigrid method to solve for the probability potentials for each unmarked point, wherein a restriction operator for the image is applied to an (N-1)%(N-1) image wherein each image weight is treated as a function of an adjoining point for application of the restriction operator, wherein said restriction operator determines weights of a coarse level grid.