- Xingzhong Du, Xuanchong Li, Xiaofang Zhou, Alexander Hauptmann. 2015. Ward-cmu @ Trecvid 2015. Abstract: We present a retrospective system for event detection in surveillance videos automatically, which is built on the Gatwick development data. It is an enhanced version of the retrospective system in [1]. The changes come from four aspects. First, dense trajectory [2] and improved dense trajectory [3] are used together in
