Improving DTW for Online Handwritten Signature Verification

Abstract

Authentication by handwritten on-line signature is one of the most accepted authentication system. In a way, it is based on biometrics. It is embedded in our cultural habits and easy to use. The aim of this paper is to study two possible improvements in Dynamic Time Warping: matching process and distance computation. After applying a polygonal approximation on the signatures, we test different approaches on the authentication problem. Usually, the information used to match the on-line signatures are the coordinates or the speed at the input data points. First, as far as the matching is concerned, we investigate other possibilities relying on the local information at each point. Next, we also test several methods to take into account local information to compute the distance. To limit genuine signature rejections, we use the result of the matching as a way to detect forgery and we also modify the computation of the distance. Finally, we evaluate the different approaches on a base of 800 signatures. The results obtained show an amelioration of the classical use of DTW.