Biometrics and Usability The User and Biometric System Uncertainty Mary Theofanos International Workshop on Usability and Biometrics June , 2008

Biometrics and Usability 22 2 The field of biometrics has tested, measured and reported performance statistics independent of the user Error Bounds are defined as combination of: uncertainty resulting from random effect uncertainty resulting from systematic effect

Biometrics and Usability 33 User Characteristics  Age  Gender  Height  Experience  Ability  Perception 3 Biometric System Factors  Anthropometrics  Affordance  Instructions  Accessibility Can we link the systematic uncertainty of fingerprint quality and performance metrics to human factors?

Biometrics and Usability 44 Habituation Study found a number of human factors that influence quality  Age: Younger participants submit higher quality images than older participants  Gender: Women’s images, on average, are of poorer quality than men’s  Feedback ◦ Habituation has no influence without feedback ◦ Older participants left higher quality images over time with feedback

Biometrics and Usability 55 Anthropometrics: Effect of Sensor Height on quality Image quality:  All fingers are sensitive to height except Right index finger  Thumbs are more sensitive to height than slaps  Left slap is more sensitive than right slap  Drop in quality from individual thumbprints to simultaneously captured thumbprints  Consistently able to provide higher quality prints for work surfaces lower than 42 inches (107 cm)

Biometrics and Usability 66 Anthropometrics: Effect of Sensor Height on Efficiency Time (Efficiency)  Counter height of 36 inches (91cm) yields fastest performance  Most efficient capture sequence starts with right hand

Biometrics and Usability 77 Instructions are significant factors for performance and quality Poster Participants:  took significantly longer to complete the 10-print collection process  made significantly more errors  only 56% were able to successfully complete the fingerprinting process  left the poorest quality images using NFIQ. Verbal and video instructions performed equally well

Biometrics and Usability 88 Operators are critical to the acquisition process  Operators are able to assist individuals to overcome the deficits of the instructional materials  With operator assistance 98% of participants were able to successfully complete the fingerprint process Verbal instructions were most preferred by participants

Biometrics and Usability 99 What about counter height and angle of the fingerprint scanner ?

Biometrics and Usability 10 We have demonstrated a link between human factors quality and performance metrics At BCC last fall Jim Wayman stated that:  Laboratory results are not a good predictor of “real-world” performance  Systematic uncertainty attributable to uncontrolled variability in human factors  Improving biometrics will require emphasis on human factors not the purely “technical” aspects