Removing noninformative subsets during vectorization of gray-level line patterns

A two-stage procedure for direct vectorization of gray-level line patterns, that bypasses the binarization phase, is illustrated. The first stage extracts the gray-skeleton of the pattern as the set of one-pixel thick subsets placed in correspondence with locally higher intensity regions. The second stage removes skeleton subsets that are noninformative for the task at hand, by taking into account parameters tailored to the problem domain. Criteria and operations employed to modify respectively peripheral and internal skeleton branches are described.