A stroke based algorithm for dynamic signature verification

Dynamic signature verification (DSV) uses the behavioral biometrics of a hand-written signature to confirm the identity of a computer user. This paper presents a novel stroke-based algorithm for DSV. An algorithm is developed to convert sample signatures to a template by considering their spatial and time domain characteristics, and by extracting features in terms of individual strokes. Individual strokes are identified by finding the points where there is a: 1) decrease in pen tip pressure, 2) decrease in pen velocity, and 3) rapid change in pen angle. A significant stroke is discriminated by the maximum correlation with respect to the reference signatures. Between each pair of signatures, the local correlation comparisons are computed between portions of pressure and velocity signals using segment alignment by elastic matching. Experimental results were obtained for signatures from 10 volunteers over a four-month period. The result shows that stroke based features contain robust dynamic information, and offer greater accuracy for dynamic signature verification, in comparison to results without using stroke features.