SUSIG: An On-line Handwritten Signature Database, Associated Protocols and Benchmark Results”

In this paper we describe a new online signature database which is available for use in developing or testing signature verification systems. The SUSIG database consists of two parts, collected using different pressure sensitive tablets (one with and one without LCD display). A total of 100 people contributed to each part, resulting in a database of more than 3000 genuine and 2000 skilled forgery signatures. One of the greatest problems in constructing such a database is obtaining skilled forgeries: people who donate to a database do not have the same motivation, nor the acquired skill of a true forger intent on passing as the claimed identity. In this database, skilled forgeries were collected such that forgers saw the actual signing process played-back on the monitor and had a chance of practicing. Furthermore, for a subset of the skilled forgeries (highly skilled forgeries), the animation was mapped onto the LCD screen of the tablet so that the forgers could watch, as well as trace over the signature. Forgers in this group were also informed of how close they were to the reference signatures, so that they could improve the forgery and forgeries that were visibly dissimilar were not submitted. We describe the signature acquisition process, approaches used to collect skilled forgeries, and verification protocols which should be followed while assessing performance results. We also report performance of a state of the art online signature verification algorithm using the SUSIG database and the associated protocols. The results of this system show that the highly skilled forgery set composed of traced signatures is more difficult compared to the skilled forgery set. Furthermore, single session protocols are easier than across-session protocols. The database is made available for academic purposes through http://biometrics.sabanciuniv.edu/SUSIG .