Given a system which detects simple events, one can define a complex event by constructing a list of sub-events. In order to recognize a complex event, the system keeps a record of the sub-events that have occurred thus far and the objects involved in these sub-events. Whenever the first sub-event in...http://www.google.com.hk/patents/US6628835?utm_source=gb-gplus-share專利 US6628835 - Method and system for defining and recognizing complex events in a video sequence
