A Medial Axis Based Thinning Strategy for Character Images

TL;DR

This paper introduces a medial axis based thinning method for character images that preserves shape and local features, producing a one-pixel wide skeleton with stroke segmentation, improving over existing methods.

Contribution

The paper presents a novel medial axis based thinning algorithm that maintains character shape and enables stroke segmentation without additional processing.

Findings

Produces a one-pixel wide skeleton

Reduces spurious branches compared to other methods

Works on printed and handwritten characters

Abstract

Thinning of character images is a big challenge. Removal of strokes or deformities in thinning is a difficult problem. In this paper, we have proposed a medial axis based thinning strategy used for performing skeletonization of printed and handwritten character images. In this method, we have used shape characteristics of text to get skeleton of nearly same as the true character shape. This approach helps to preserve the local features and true shape of the character images. The proposed algorithm produces one pixel width thin skeleton. As a by-product of our thinning approach, the skeleton also gets segmented into strokes in vector form. Hence further stroke segmentation is not required. Experiment is done on printed English and Bengali characters and we obtain less spurious branches comparing with other thinning methods without any post processing.