1. A method of semantic object tracking of an object depicted in a first, second, and third video frame, the object having a precise border, the method comprising: (a) defining an initial approximate boundary near the border of the object in the first frame; (b) defining an inner boundary inside the approximate boundary; (c) defining an outer boundary outside the approximate boundary; (d) expanding the inner boundary and contracting the outer boundary to identify an outline corresponding to the border of the object on the first frame; (e) identifying a motion transformation function representing the transformation between the object in the first frame and the object of the second frame; (f) warping the outline according to the motion transformation function to define a new approximate boundary for object in the second frame; and (g) repeating steps (b) through (d) with the new approximate boundary so as to automatically track the boundary of the object between the second and third frames.