One-pass parallel hexagonal thinning algorithm

A comparison between two fully parallel thinning algorithms designed for images sampled on the square and hexagonal grids is reported. Using techniques from mathematical morphology, a hexagonal algorithm has been designed to closely match the operation of a well known square grid algorithm. Proofs of the connectivity and single pixel limb width of the resulting converged hexagonal skeleton have been presented. Implementations of both algorithms were found to produce accurate skeletons, but the hexagonal could be implemented with only 50% of the logical operations required by the square.