Method and system for defining and recognizing complex events in a video ...

1. A computer implemented method for recognizing complex events in a sequence of video images comprising the steps of:

defining at least one complex event as an ordered list of a predetermined number of events;

recognizing simple events in the sequence of video images;

upon recognition of a simple event

determining if said recognized simple event is a first event in said set ordered list of events of a complex event, and if so activating a complex event recognition process for said corresponding complex event and initializing an index for said complex event recognition process to 1;

determining if said recognized simple event is a next event in said ordered list of events of an activated complex event recognition process, and if so logging said recognized event in said complex event recognition process and incrementing said index of said complex event recognition process; and

determining if all events in an activated complex event recognition process have been detected by determining if said corresponding index equals said predetermined number of events in said corresponding complex event, and if so recognizing said corresponding complex event.

2. The computer implemented method of claim 1, wherein:

said step of defining at least one complex event comprises defining a complex event including another defined complex event;

said method further comprises upon recognition of a complex event

determining if said recognized complex event is a first event in said ordered list of events of another complex event, and if so activating a recognition process for said corresponding complex event and initializing an index for said other complex event recognition process to 1;

determining if said recognized complex event is a next event in said ordered list of events in an activated complex event recognition process, and if so logging said recognized event in said complex event recognition process and incrementing said index of said complex event recognition process; and

determining if all events in an activated complex event recognition process have been detected by determining if said corresponding index equals said predetermined number of events in said corresponding complex event, and if so recognizing said corresponding complex event.

3. The computer implemented method of claim 1, wherein:

said step of defining a complex-event comprises defining a complex event includes at least one negated event;

said method further comprises the steps of upon recognition of an event determining if said recognized event matches a non-negated event corresponding to a next negated event in said ordered list of an activated complex event recognition process,

if so deactivating said complex event recognition process, and

if not determining if said recognized event matches a next non-negated event of an activate complex event recognition process, and if so logging said recognized event and all intervening negated events in said complex event recognition process and incrementing said index for said recognized event and for each intervening negated event.

4. The computer implemented process of claim 3, wherein:

said step of defining a complex event includes an initial negated event; and

said method further comprises determining if said recognized event matches a non-negated event corresponding to said initial negated event of a complex event, and if so disqualifying a corresponding tracked object relative to said corresponding complex event.

5. The computer implemented process of claim 3, wherein:

said step of defining a complex event includes a final negated event; and

said method further comprises upon detection of a final non-negated event in said corresponding complex event, recognizing said complex event if no detection of said negated event occurs within a predetermined period of time.

6. The computer implemented process of claim 3, wherein:

said simple events include an EXIT event wherein an object previously present in said sequence of video images is no longer present;

said step of defining a complex event includes a final negated event; and

said method further comprises upon detection of a final non-negated event in said corresponding complex event, recognizing said complex event if no detection of said negated event occurs before a corresponding object EXITs.