Fig. 6.
Privacy-utility tradeoff scores are depicted. The tradeoff is the weighted sum of bystander privacy (inverse of the ability to detect bystander activity and bystander concerns) and the accuracy of visual confirmation of the wearer’s activity. The top row shows the tradeoff (th2h) when the utility is related to the wearer hand-to-head activities (i.e., contextual information needed to identify the activity is not obfuscated). The bottom row shows the tradeoff (tall) when utility for both hand-to-head (H2H) and non-H2H activities (i.e., the case when important contextual information related to the activity) might be obfuscated. We also show the tradeoff score using different weights: (1) favoring utility, (2) favoring privacy, and (3) equal weights. Partial obfuscation using mask provides the best balance in privacy-utility tradeoff when the context is not needed to identify the activity, while blur provides the best balance in this tradeoff when context helps in identifying the wearer activity.