US Patent 8009911 Interactive image segmentation on directed graphs

Methods for segmentation of an object from a background in an image are disclosed. Segmentation is achieved by an adapted Random Walker segmentation method using directed edges in a graph. The segmentation applies the minimization of an approximation of an energy function. A minimizer of the approximated energy function can be found by using iterative steps. Weights are assigned to an edge between two nodes. The weights are dependent on the direction of an edge. A system for segmentation of an object from a background is also disclosed.