In this paper,we propose an on-line writer identification system characterizing velocity and areal velocity of pen-tip movement in handwriting process. The writer identification system consists of two finite impulse response (FIR) systems characterizing the velocity and areal velocity in handwriting process. Individual handwriting feature is represented by the impulse response of the FIR system. Writer can be identified by evaluating the difference between the impulse responses of the FIR systems for the reference and a person to be identified. In our experiments 2,000 Thai numerals were used to identify 10 different writers.
