MediaEval 2013 Visual Privacy Task: Physics-Based Technique for Protecting Privacy in Surveillance Videos

This paper describes a physics-based technique for protecting the privacy of people in videos as defined by the MediaEval 2013 Visual Privacy task. We propose a physics-based approach which estimates the full spectrum of the surface spectral reflectance from the video. Whereby the wavelength which corresponds to the global minimum of the spectral curve (an intrinsic feature of the material) at a pixel is calculated and converted to RGB values which are used to filter pixels that belong to a moving object. This effectively implements visual privacy protection by replacing foreground pixel colour by another which is related to intrinsic optical properties of the original pixel. Both objective and subjective evaluations are performed using both video analytics algorithm and user studies in order to evaluate the proposed technique.