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

Due to the technological evolution and the increas-ing popularity of smartphones, people can access an ap-plication with many different devices. This device inter-operability is a very challenging problem for biometrics. In this paper we focus on inter-operability device compensa-tion for on-line signature verification. The proposed ap-proach is based on two main stages. The first one is a pre-processing 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 de-vice comparisons in order to select features which are ro-bust 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 sys-tem. Also, the proposed approach provides average rela-tive improvements for the cases of inter-operability compar-isons 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 re-sults open the door for future works using devices as smart-phones or tablets, commonly used nowadays. 1