- A luggage is owned and attended to by a person who enters the scene with the luggage until the point at which the luggage is not in physical contact with the person.
- At this point the luggage is attended to by the owner ONLY when they are within a distance of 20 inches (spatial rule). All distances are measured between Euclidean distances.
- A luggage item is unattended when the owner is farther than b meters (where b ≥ a from the luggage. In this case the system applies the spacio-temporal rule to detect whether this item of luggage has been abandoned (triggering an alarm event).
- The spacio-temporal rule to determine abandonment: an item of luggage that has been left unattended by its owner for a period of t consecutive seconds during which time the owner has not re-attended to the luggage nor has the luggage been attended to by a second party (instigated by physical contact, in which case a theft/tampering event may be raised). The image below (Figure 7) shows an item of luggage left unattended for t (=10) seconds, at which point the alarm event is triggered. Here we relate the time t with the number of frames f per second. If we have n frames per second in our input video, t seconds would be defined as (t*f) frames. In short, a bag that has been unattended in (t*f) consecutive frames triggers the alarm.