Modified Dynamic Time Warping for Stroke-Based On-line Signature Verification

In the stroke-based signature verification system, it is important to find correct points of a testing signature to be spilt according to its template signature. In this paper, we propose a modified dynamic time warping algorithm (DTW) for the problem. Proposed method has two differences to the conventional approaches. First, the stroke information of both template and testing signature is considered precious to prevent wrong splitting. Second, the number of stroke difference in genuine signature is not limited because the proposed method does not require much additional computational time. Through the experiment, proposed method is verified with 1359 signatures written by 17 Japanese writers. The test data were all the semi-skilled forgeries, and the results of proposed methods showed 3.85% in the equal error rate (the error rate when the false acceptance rate and false rejection rate is the same; EER) while the EER of the compared method was 7.8%.