Issue No. 10 - October (2005 vol. 27)
Ahmed and Ward  have recently presented an elegant, rule-based rotation-invariant thinning algorithm to produce a single-pixel wide skeleton from a binary image. We show examples where this algorithm fails on two-pixel wide lines and propose a modified method which corrects this shortcoming based on graph connectivity.
Index Terms- Thinning, skeletonization, graph theory.
Peter I. Rockett, "An Improved Rotation-Invariant Thinning Algorithm", IEEE Transactions on Pattern Analysis & Machine Intelligence, vol. 27, no. , pp. 1671-1674, October 2005, doi:10.1109/TPAMI.2005.191