1. Biometrics and Usability The User and Biometric System Uncertainty Mary Theofanos International Workshop on Usability and Biometrics June 23- 24, 2008

2. 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

3. 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?

4. 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

5. 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)

6. 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

7. 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

8. 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

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

10. 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