A unit decomposition technique using fuzzy logic for real-time handwritten Chinese character recognition

The purpose of this paper is to provide a real-time compact device for inputting handwritten characters to mobile personal digital assistants (PDAs). A novel method for the recognition of online handwritten Chinese characters is presented, giving emphasis to the representation of the patterns using fuzzy logic. The information contained in a character, including shapes of individual strokes and their relative spatial relations, is examined by inference of fuzzy rule base, and the fuzzified representation is organized in a matrix structure. It is well known that Chinese characters are comprised of a set of basic units, representing fundamental meanings. Hence, a unit extraction module is designed to search the possible units within characters. The input character object is recognized by a combination of units with the largest fuzzy confidence degree. The training capability, which provides the unit model set, is performed using the qualitative fuzzy c-means clustering algorithm. An experimental system is implemented that achieves a real-time recognition rate of about 95% with a test set of 550 characters and two cases for each character written by six users. The experimental system has an average real-time recognition speed of 0.5 s/character. The presented approach shows the following two significant advantages over other methods: (1) less training time; and (2) less storage required to store character models. These are two crucial factors in designing PDA devices for mobile communication.