Querying Multiple Simultaneous Video Streams with 3D Interest Maps

International audience; With proliferation of mobile devices equipped with cameras and video recording applications, it is now common to observe multiple mobile cameras filming the same scene at an event from a diverse set of view angles. These recorded videos provide a rich set of data for someone to re-experience the event at a later time. Not all the videos recorded, however, show a desirable view. Navigating through a large collection of videos to find a video with a better viewing angle can be time consuming. We propose a query-response interface in which users can intuitively switch to another video with an alternate, better, view, by selecting a 2D region within a video as a query. The system would then response with another video that has a better view of the selected region, maximizing the viewpoint entropy. The key to our system is a lightweight 3D scene structure, also termed 3D interest map. A 3D interest map is naturally an extension of saliency maps in the 3D space since most users film what they find interesting from their respective viewpoints. A user study with more than 35 users shows that our video query system achieves a suitable compromise between accuracy and run-time.