MiamiMapper: Crowd Analysis using Active and Passive Indoor Localization through Wi-Fi Probe Monitoring.

Crowd analysis and monitoring in large congregations is an important problem related to public safety and planning. Researchers have long been using image and video for effective crowd analysis. However, with the advent of more sophisticated technologies, crowd monitoring has been attempted using GPS, RFID as well as Bluetooth based systems. Indoor crowd monitoring in public buildings, such as, airport, museum, theaters, etc. has not been widely studied with regards to systems that are not integrated with the indoor environment, such as Wi-Fi access points. In this paper, we propose a non-invasive Wi-Fi based approach for indoor crowd analysis which works by passively monitoring the probe packets generated by smartphones. Since smartphones, and other smart devices, nowadays can be unequivocally associated with a human user, counting unique MAC addresses of smartphones can generate a fairly close estimate of number of users in the indoor space and their movement patterns. In this paper, we have developed the MiamiMapper system, from COTS hardware and software, for crowd analysis in indoor environment using passive monitoring of probe packets emitted by wireless devices. Our system can localize users and thereby detect crowd movement using probe counts with an average accuracy of 7.28 meters.