The use of hidden deletable pixel detection to obtain bias-reduced skeletons in parallel thinning

Bias skeletons yielded by thinning patterns which usually degrade the preservation of significant geometric features of patterns are addressed in this paper. Based on the considerable performance of our pseudo 1-subcycle parallel thinning algorithm, we continuously adopt it to develop an intermediate vector analysis about the removed pixels in each normal iteration to obtain bias-reduced skeletons. The hidden deletable pixel which is a major factor to yield bias skeletons is newly defined and can be detected by the presented algorithms of vector analysis