Automating visual privacy protection using a smart LED

Abstract

The ubiquity of mobile camera devices has been triggering an outcry of privacy concerns, whereas existing privacy protection solutions still rely on the cooperation of the photographer or camera hardware, which can hardly be enforced in practice. In this paper, we introduce LiShield, which automatically protects a physical scene against photographing, by illuminating it with smart LEDs flickering in specialized waveforms. We use a model-driven approach to optimize the waveform design, so as to ensure protection against the (uncontrollable) cameras and potential image-processing-based attacks. We have also designed mechanisms to unblock authorized cameras and enable graceful degradation under strong ambient light interference. Our prototype implementation and experiments show that LiShield can effectively destroy unauthorized capturing while maintaining robustness against potential attacks.