Person Leaving Detection: Operator & Staff Presence

A position that must be staffed fails quietly. The console operator steps out for a cigarette and the cigarette becomes half an hour; the gatehouse attendant leaves early and the barrier runs unwatched until someone notices. Person leaving detection closes that gap on the cameras already in place: when someone leaves a zone that must stay occupied, and stays gone past the grace period you set, the system alerts while the position is still empty.

Person leaving detection runs person detection against each defined zone and tracks presence over time. The rule is not “did anyone walk past” – it is “is the person whose job keeps them here actually here”. That distinction drives every setting: the zone is drawn around the post itself, the presence threshold is tied to the roster, and the alert fires only when the configured occupancy condition breaks.

What the Rule Watches

Each monitored post is drawn as a zone – a control-room console, a gatehouse desk, a first-aid station, a supervisor’s station on a production line. You define the occupancy policy per zone: whether the rule requires someone present continuously, allows brief absences up to a set time, or applies only during specific hours. While the policy is active, the rule runs on the edge appliance against the camera’s stream and maintains a presence timeline for the post.

The timeline is as useful as the alarm. Every occupied and vacant period is recorded, so end-of-shift reviews become checkable facts rather than recollections, and a contractor’s claim of coverage can be verified against the record. Grace periods absorb legitimate movement – a washroom trip, a handover walk-through – and the vacancy timer cancels the moment someone re-enters the zone.

How It Works on the Edge

The rule builds on object detection and runs entirely on the edge appliance beside the cameras. Presence logic needs dwell reasoning – the same principle used throughout video analytics – because a person briefly stepping behind a cabinet or leaning out of frame must not register as a departure. The vacancy timer starts only after the grace period expires and the zone remains empty, which is what keeps false alarms at a level operators will tolerate.

Because the analytics run locally, the rule keeps working through network outages – precisely the condition under which an unwatched post is most exposed. Alerts queue on the appliance and deliver when the link returns, with the local record intact.

How It Differs from the Related Rules

Three neighbouring rules cover the other failure modes, and drawing the boundaries clearly prevents over-buying. Workstation abandonment detection targets a specific workstation – typically a single desk and its monitor – and flags when the equipment is left unattended; person leaving detection is broader, covering any zone where a person must stay, including posts without a defined workstation. Under-staffing detection answers the count question – how many people a post requires, minimum two or none – while person leaving detection answers the transition question: someone was there and is now gone. Sleeping on duty detection covers presence in body but not in function. Sites commonly run them together on the same cameras, since one appliance carries all three.

Where Sites Use It

Manufacturing lines use it on safety-critical stations – a press station, a chemical dosing point, a crane cab – where a line that keeps running with nobody at the controls is a reportable event, not just a productivity loss. The same cameras usually carry fall detection in the areas where lone work is riskiest.

Security operations use it on gatehouses and control rooms during contracted hours, where the post record doubles as contract-compliance evidence. Care facilities apply it to nurse stations and monitoring posts, pairing it with the resident-side view described in elderly fall detection. Retail back-of-house uses it on cash-office doors during counting windows, alongside AI cameras in retail stores on the sales floor. Perimeter posts extend the value into night hours, where the same camera feeds intrusion detection on the fence line and loitering detection at the approach – an empty gatehouse and a person circling the gate is the combination worth waking someone for.

For the background on how this works, see virtual fence system.

For the wider context around this, see how face detection works.

Frequently Asked Questions

How long away counts as leaving?

That is your grace period, set per zone. Three minutes may be acceptable for a gatehouse attendant during a quiet shift, while a control-room console during operations might allow none. The timer only starts when the zone is fully empty, and it cancels the instant someone returns – a walk-through does not count as a departure.

Can it tell a shift change from an actual departure?

Yes, by scheduling. You set the hours each occupancy policy is active and add a handover window around shift changes, when two people briefly overlap or the post is deliberately vacated. Outside the policy’s active hours, the rule stays quiet.

Does one camera cover several posts?

Yes, if the angle supports it. Each post is its own zone with its own policy and grace period, so a single camera overlooking two desks can enforce different absence rules for each. Where an angle cannot clearly see a post, we flag it during evaluation rather than after the first missed alert.

What if the person is temporarily out of frame?

Brief occlusion is handled by the dwell logic – a person crouching behind a desk or stepping out of frame for a few seconds does not trigger the timer. The vacancy clock starts only after the grace period with the zone genuinely empty, which is the setting that tunes sensitivity to your site’s reality.

Next Step

Send us the post layout and the occupancy policy each position requires. From the 198+ algorithm library this is configuration, not development – the first demo takes about 7 days where the detection already exists in the library. Start with a Starter Kit at USD 999, or tell us your scenario for a custom build quoted per site.