Automatic signature verification using a three-axis force-sensitive pen

A performance analysis of an automatic signature-verification system based upon the use of a three-axis force-sensitive pen to transduce the dynamics of the handwritten signature into electrical signals suitable for real-time computer processing is presented. False-rejection and imposter-acceptance (i.e. type I/type II error) curves are presented for a variety of operating conditions. For typical `real world´ conditions, the equal-error rate (where type I error rate equals type II error rate) is about one percent. The performance analysis was based upon a data base of 5220 true signatures obtained from 58 subjects over a four- month period, and 648 attempted forgeries obtained from 12 forgers. The forgers were given copies of the true signers´ signatures, told how the verification system operates and what it measures, allowed to watch video tapes with close-up views of the signatures to be forged as they were being written, and allowed to practice for a three-week period. Particular advantages of the signature-verification system reported here are high performance, low storage requirements (typically 200 to 300 bits per user), and low-cost implementation in a stand-alone microprocessor unit.