Retrieving geo-location of videos with a divide & conquer hierarchical multimodal approach

This paper presents a strategy to identify the geographic location of videos. First, it relies on a multi-modal cascade pipeline that exploits the available sources of information, namely the user's upload history, his social network and a visual-based matching technique. Second, we present a novel divide & conquer strategy to better exploit the tags associated with the input video. It pre-selects one or several geographic area of interest of higher expected relevance and performs a deeper analysis inside the selected area(s) to return the coordinates most likely to be related to the input tags. The experiments were conducted as part of the MediaEval 2012 Placing Task. Our approach, which differs significantly from the other submitted techniques, achieves the best results on this benchmark when considering the same amount of external information, i.e. when not using any gazetteers nor any other kind of external information.