Stroke extraction method for offline recognition of Chinese characters

Abstract

A structural method for analysis of Chinese characters is presented, with the purpose of handwritten character recognition. Firstly, a line following and thinning process is used to obtain the thinned shape of the character. This process includes a specific treatment of singular regions allowing the detection of the branching points. In a second stage, an extended direction code is assigned to each point of the thinned line. Then, median filtering of extended codes eliminates much of the quantization noise, without altering significant direction changes. This leads to split up the character into a list of straight line segments, which are characterized by a main direction attribute. In a third stage, strokes are extracted by bringing together adjoining segments having neighboring directions. To compare two characters, firstly, we try to associate to each stroke of the first character the nearest stroke of the second one. Then, the distance between both characters is obtained from the sum of the distances between strokes, associated by pairs. This distance takes into account the possible presence of non- paired strokes in both characters.