A method of incorporating user supplied information in level-set based image segmentation includes providing a digital image comprising a plurality of intensities corresponding to a domain of points, providing an embedding function on the image domain, obtaining from a user a control point in the image, selecting two end points from the image, the end points being in a level set of the embedding function, interpolating an interactive segment from the user supplied control point and the two end points, replacing a curve segment in the level set between the two endpoints with the interactive segment to form a shape constraint, and time-evolving the embedding function so as to minimize the difference between the level set of the embedding function and the shape constraint.