Apply djkstra algorithm to trace contour

trace single object's contour via the classic shortest path algorithm

please run the follows commands to duplicate the
screenshot:

mex vcTraceContour.cpp %complie only onece
im = imread('h.gif'); [x, y] = traceContour(~im);
Note:
a. The core cpp routine which implement the shortest path routing is in 'cShortestPath', which with computational complexity of O(N*log(N)), where N is the perimeter of the object.
b. the input image must contains only one object(white area.)