Crowd and event detection by fusion of camera images and micro blogs

In this paper, we propose a new application to infer the “cause” of human crowd (scheduled events, sudden accidents and so on) by mobile crowd sensing. The idea is that we leverage our phone-camera-based, crowd-sourced people counting to firstly localize an event with human crowds, and then extract keywords that spatiotemporally correspond to the event from micro blogs such as tweets. Such keywords are further analyzed to find out the most-frequent ones, which can be used to characterize the detected human-crowd event and to estimate its cause. We demonstrate our prototype design using real camera images and tweets to automatically detect the Halloween street party in Tokyo and estimate its human density.