Continuous authentication of mobile user: Fusion of face image and inertial Measurement Unit data

Mobile devices can carry large amounts of personal data, but are often left unsecured. PIN locks are inconvenient to use and thus have seen low adoption (33% of users). While biometrics are beginning to be used for mobile device authentication, they are used only for initial unlock. Mobile devices secured with only login authentication are still vulnerable to data theft when in an unlocked state. This paper introduces our work on a face-based continuous authentication system that operates in an unobtrusive manner. We present a methodology for fusing mobile device (unconstrained) face capture with gyroscope, accelerometer, and magnetometer data to correct for camera orientation and, by extension, the orientation of the face image. Experiments demonstrate (i) improvement of face recognition accuracy from face orientation correction, and (ii) efficacy of the prototype continuous authentication system.