  Most existing image privacy protection works focus mainly on the privacy of
photo owners and their friends, but lack the consideration of other people who
are in the background of the photos and the related location privacy issues. In
fact, when a person is in the background of someone else's photos, he/she may
be unintentionally exposed to the public when the photo owner shares the photo
online. Not only a single visited place could be exposed, attackers may also be
able to piece together a person's travel route from images. In this paper, we
propose a novel image privacy protection system, called LAMP, which aims to
light up the location awareness for people during online image sharing. The
LAMP system is based on a newly designed location-aware multi-party image
access control model. The LAMP system will automatically detect the user's
occurrences on photos regardless the user is the photo owner or not. Once a
user is identified and the location of the photo is deemed sensitive according
to the user's privacy policy, the LAMP system will intelligently replace the
user's face. A prototype of the system was implemented and evaluated to
demonstrate its applicability in the real world.
