"A Convex Geodesic Selective Model for Image Segmentation" DOI: 10.1007/s10851-018-0857-2
Journal of Mathematical Imaging and Vision , Volume 61 (5), pp:482-503
See PDF file.
See the left images for an example of selection by 3 vertices and the computed geodesic map D before segmentation.
(Note: the interested feature is almost "located" by D alone. Clearly this is great for segmenting low contrast images)