“…There are many applications in the biosciences, computer vision, medical, and pattern recognition communities where guidance by human experts is required [7,20,27,48,50]. The current interactive GPU level set methods, such as [36], provide interfaces to (1) initialize / inside/outside the object, (2) dynamically adjust parameters, and in some cases (3) allow / to be edited (a union operator on new objects/regions, followed by rerunning of the algorithm); however, it is difficult to refine evolution such as to prevent contour leaking or constrain the evolution.…”