DéjàVu

Abstract

With demanding and sophisticated crimes and terrorist threats becoming ever more pervasive, it is paramount to design and develop objective approaches to help us solving the four most important questions in forensics regarding an event: “who”, “in what circumstances”, “why”, and “how”. Although aided by surveillance cameras when answering such questions, we often face situations in which cameras are not installed or are insufficient to cover the event. Leveraging on the rise of social media content recent explosion and wide spread, we could rely on this new channel with orders of magnitude increase in the volume of content available for event understanding and reconstruction. The aim is to complement the content from existing, if any, surveillance cameras at the event location. We could potentially provide a much clearer “bird’s eye view” of an event, along with reconstructed scenes from various perspectives of people or objects present as well as mine information related to the event pouring from social media. In this context, given an event to be investigated, our objective is to gather social media information related in position and time to such event and mine the collected information to understand what happened, reconstruct the event’s timeline, narrow down the space-search of suspects and come up with possible answers to the four aforementioned forensics questions.