MediaEval 2014 Visual Privacy Task: Geometrical Privacy Protection Tool

This paper describes EPFL privacy protection tool for the MediaEval 2014 Visual Privacy task. The goal of the task is to obscure faces, body silhouettes, and personal items of people in the provided surveillance clips to preserve their personal privacy. The EPFL privacy protection tool mainly relies on two privacy protection filters: a warping-based reversible filter to obscure features with low visual details (body silhouettes) by distorting them with randomized warping and morphing-based reversible filter to obscure features with high visual details (faces and personal items) by ‘replacing’ them with a graphical representation. The aim of this tool is to achieve an acceptable balance between privacy (how well the privacy is protected) and intelligibility (how well the surveillance task can still be performed), as well as, privacy and pleasantness (how pleasant is the protection). The results of three types of subjective evaluations, via crowdsourcing, practitioners, and stakeholders, provided by the organizers of the task demonstrates that EPFL privacy protection tool achieves a great overall balance between privacy, intelligibility, and pleasantness, while being secure and reversible in the same time.