Definition, Detection, and Evaluation of Meeting Events in Airport Surveillance Videos
Sung Chun Lee, Chang Huang, Ram Nevatia · 2008
Detection of events in the surveillance video selected for TRECVID 2008 is an extremely difficult task. It was not possible for us to evaluate on a variety of events and the entire length of the dataset. We participated in an exploratory task and selected a single “people meeting ” event. This event was selected due to its frequency, importance and difficulty. It is actually a collection of similar tasks as there can be several styles of meeting: for example two people coming towards each other, one person waiting for others, a person joining an existing group etc. Difficulty of the task can vary based on the density of the crowd in the scene at the moment and the extent to which the participants are occluded. It is not too useful to just combine the results of all these conditions and simply average; we selected video segments where participants are partly occluded and the crowd density is "medium". We first detect and track pedestrians using an existing tracking method; in fact, tracking in this complex environment is the strongest challenge for the task. Then, we detect meeting events based on analysis of the trajectories. We present results which include the precision and recall rates and some graphical results. 1.