Measuring the Symmetry of Digital Ink Chinese Characters Handwritten by CFL Beginners Based on Knowledge Base

Abstract

Symmetry is a structural feature of Chinese characters which influences the aesthetics of the whole character. Beginners to Chinese as a foreign language (CFL) often tend to write asymmetrical characters due to insufficient knowledge of Chinese character orthography and a lack of skill in the strokes. Symmetry deviations in the handwriting characters are usually assessed manually. However, this task is time-consuming and somewhat subjective, with potentially inconsistent results when evaluated by different people. The aim of this paper is to propose a bilateral symmetry measurement approach that uses the center of gravity of Chinese characters (CGCC) and convex hull vertices, both of which are obtained by digital ink technology, to construct the symmetry axis (SA) and detect symmetry point pairs (SPPs) of Chinese characters, computing the symmetry score (SS) of Chinese characters from the horizontal and vertical symmetry of SPPs. In addition, a symmetry information knowledge base is constructed to label the SS of standard reference characters and to measure the symmetry of handwritten characters by comparing the differences between the SS of them and that of the reference characters in the knowledge base. Experiments with digital ink character data from CFL beginners have proven that the proposed method is effective.