Stroke-based time warping for signature verification

Abstract

This paper presents a new technique for dynamic signature verification. A dynamic programming (DP) approach is used for function-based signature verification. Dynamic data such as pressure is treated as a function of positional data and therefore evaluated locally. Verification is based on strokes as the structural units of the signature. This global knowledge is fed into the verification procedure. The application of a 3D non-linear correlation of the signature signals uses the stroke index as the third DP index. In conjunction with the definition of a finite state automaton on the set of reference strokes the system can handle different stroke numbers, missing or additional strokes correctly. The correct alignment of matching strokes is determined simultaneously to the signature verification process; an additional alignment stage before the actual nonlinear correlation is obsolete.