On-line writer recognition for Thai numeral

This paper discusses an on-line writer recognition for Thai numerals. First, a center point of a Thai numeral is determined after normalization. Then the center point is shifted to an origin. Secondly, the distance from the origin to the pen-point position in the handwriting process is measured and the area of a triangle determined from the origin and the two adjacent points of the pen-point position is calculated. Thirdly, the features of pen-point movement in the process are extracted by expanding the time sequence of the above distance and area into Fourier series. Then the features of pen-point movement are represented in terms of Fourier coefficients. Fourthly, in order to describe the handwriting process features, the FIR system with the above coefficients as input and output of the system is introduced. Then the impulse response of the FIR system is used as the feature of handwriting process. Furthermore in order to recognize the writer, K-L expansion (J.T. Tou and R.C. Gonzalez "Pattern Recognition Principles", Addison-Wesley, pp. 269, 1974) of the obtained impulse response is used. In the experiments, the average rates of type I (false rejection) and type II (false acceptance) error were 17.14% and 9.26%, respectively.