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Browse Prior Art Database

Quadrant Check for Signature Verification

IP.com Disclosure Number: IPCOM000089142D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Larsen, LD: AUTHOR

Abstract

Fig. 1 illustrates an instrumented pen or stylus 1 having two bimorph crystal sensors 2 and 3, which are mounted on orthogonal axes within the pen body 1. When pen 1 is accelerated by a user's hand in writing a signature or other descriptive reproducible mark, accelerometers 2 and 3 will experience deflections in the Y and Y plane, as illustrated in the cross-sectional view in Fig. 2. The crystals 2 and 3 will respond to motions transverse to their axes primarily, and may produce plus or minus signals in both the X and Y axes. This situation is illustrated in Fig. 3, where the quadrants in the X and Y axes are shown with a time varying X and Y combined signal that might be produced by typical motion of an instrumented pen.

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Quadrant Check for Signature Verification

Fig. 1 illustrates an instrumented pen or stylus 1 having two bimorph crystal sensors 2 and 3, which are mounted on orthogonal axes within the pen body 1. When pen 1 is accelerated by a user's hand in writing a signature or other descriptive reproducible mark, accelerometers 2 and 3 will experience deflections in the Y and Y plane, as illustrated in the cross-sectional view in Fig. 2. The crystals 2 and 3 will respond to motions transverse to their axes primarily, and may produce plus or minus signals in both the X and Y axes. This situation is illustrated in Fig. 3, where the quadrants in the X and Y axes are shown with a time varying X and Y combined signal that might be produced by typical motion of an instrumented pen. At any given point in time a particular point 4 along this output curve can be identified as a point terminating a vector from the origin in the X and Y axes. By keeping an account of the total amount of time that the acceleration vector remains in each quadrant, for example, by keeping four separate time counts for the quadrants, a representation of the signature as executed by the authentic individual can be obtained for comparison with previously gathered quadrant totals for that individual as a reference. The percent of total signature time spent in each quadrant may also be used to this end and is a better technique since it accounts for variations in signature writing time by the individual.

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