A 1-subcycle parallel thinning algorithm for producing perfect 8-curves and obtaining isotropic skeleton of an L-shape pattern

The authors review their pseudo-one-subcycle parallel thinning algorithm. They present two improved versions of this algorithm, and describe a two-stage structure to realize the one-subcycle parallel algorithm. The first stage is to produce a perfect 8-curve excluding T-junction thin line. The second is to obtain the isotropic skeleton of an L-shaped pattern. The two stage structure consists of a thinning table and a control unit. The thinning table is used to provide the attributions for an input 3×3 local pattern. The control unit is used to check the removal of the center pixel of this local pattern, and the inputs of the control unit also comprise the outputs of other neighboring thinning tables. This structure can exactly implement the proposed one-subcycle parallel algorithms. The two improved algorithms have been implemented. Experiments confirm that the improved algorithms can produce the desired effective thin line and also show that the structure realized is feasible and practicable