Average prototypes for stroke-based signature verification

A signature verification system basically consists of two units, the verification and the enrolment subsystem. Much work has been done developing verification techniques for dynamic signature verification whereas the influence of reference construction has not been extensively studied. The paper reports how the verification rates of a given system can be increased by ameliorating the enrolment technique. An efficient enrolment technique that performs a time- and position-based averaging of representative input signatures for a stroke-based verification approach is presented. The approach is capable of dealing with varying stroke structures, missing or additional strokes, and, in the presence of those, determines the most natural stroke structure of the reference in parallel with the construction of the average signature prototype. It is shown that, in comparison to the frequently used technique of selecting one signature out of an initial set of input signatures, the error rate especially of stroke-based approaches can be significantly reduced.