Optimal feature selection and inter-operability compensation for on-line biometric signature authentication

Due to the technological evolution and the increasing popularity of smartphones, people can access an application with many different devices. This device interoperability is a very challenging problem for biometrics. In this paper we focus on inter-operability device compensation for on-line signature verification. The proposed approach is based on two main stages. The first one is a preprocessing stage where data acquired from different devices are processed in order to normalize the signals in similar ranges. The second one is based on a feature selection of time functions taking into account the inter-operability device comparisons in order to select features which are robust in these conditions. The experimental work has been carried out with Biosecure database using a Wacom tablet (DS2) and a PDA tablet (DS3), and the system developed is based on dynamic time warping (DTW) elastic measure over the selected time functions. The performance of the proposed system is very similar compared to an ideal system. Also, the proposed approach provides average relative improvements for the cases of inter-operability comparisons of 26.5% for random forgeries and, around 14.2% for the case of skilled forgeries comparing the results with the case of having a system specifically tuned for each device, proving the robustness of the proposed approach. These results open the door for future works using devices as smartphones or tablets, commonly used nowadays.