Automatic User Authentication for Privacy-Aware Human Activity Tracking Using Bluetooth Beacons

In this paper, we introduce a novel mechanism to facilitate automatic user authentication for privacy-aware vision based human activity tracking. The mechanism relies on the Bluetooth beacon technology, which localizes a user who is present in the field of view of a camera. Unlike our previous mechanism designed for the same purpose, which requires a user to push a button on the smartwatch he or she is wearing and make a predefined gesture to register with the activity tracking system, this new mechanism does not require the user to alter his or her work routine when entering the view of the tracking system. Hence, the proposed mechanism significantly increases the usability of the tracking system. While the importance of automatic user authentication might not be obvious to researchers, it is essential for the acceptance of the activity tracking technology in its intended venues where workers will be monitored on their jobs as demonstrated by our previous field study and by our interviews with business owners. We report the experimental result based on two types of Bluetooth beacon devices, one from Estimote, and the other from Gimbal. Through the experiments, we identify several challenges in using these commercial-off-the shelf beacon devices for automatic user authentication, including the lack of synchronized beacon signal transmission by different beacon devices, nonuniform beacon transmission with occasional large gaps, and delay in beacon signal detection or reporting, and propose solutions to these issues.