Mukherjee,Jayanta, Kumar A., Das,P.P. and Chatterji,B.N. (2002):
Use of Medial Axis Transforms for computing normals at boundary points,
Pattern Recognition Letters, vol. 23, 14, pp. 1649-1656.  Abstract. 
Medial axis transform (MAT) is well known for object representation. It is interesting to explore its use in different kinds of computations. In this paper an algorithm has been proposed for computation of normals at the boundaries of 2D objects based on their medial axis transforms. In this technique, there is no requirement of linking boundary points during the computation compared to other existing techniques. The added advantage in the computation is that the computation can be restricted purely in the integer domain.