David Wyld at SecureID News pens an indepth look at the technology and methodology behind the Biometric Scanners that Disney theme parks use to associate you with your admission media.
Operationally, finger or hand scanning systems capture the physical,
geometric characteristics of an individual’s hand – with most systems
having the capacity to do so in less than a second. From these
measurements, a profile or “template” is constructed which will be used
to compare against subsequent readings by the user.