Cardea: Context-Aware Visual Privacy Protection for Photo Taking and Sharing

The growing popularity of mobile and wearable devices with built-in cameras and social media sites are now threatening people's visual privacy. Motivated by recent user studies that people's visual privacy concerns are closely related to context, we propose Cardea, a context-aware visual privacy protection mechanism that protects people's visual privacy in photos according to their privacy preferences. We define four context elements in a photo, including location, scene, others' presences, and hand gestures. Users can specify their context-dependent privacy preferences based on the above four elements. Cardea will offer fine-grained visual privacy protection service to those who request protection using their identifiable information. We present how Cardea can be integrated into: a) privacy-protecting camera apps, where captured photos will be processed before being saved locally; and b) online social media and networking sites, where uploaded photos will first be examined to protect individuals' visual privacy, before they become visible to others. Our evaluation results on an implemented prototype demonstrate that Cardea is effective with 86% overall accuracy and is welcomed by users, showing promising future of context-aware visual privacy protection for photo taking and sharing.