objects moving between zones

[turboc1208]

I know this is an old question sorry for rehashing it. I read a post from back in 2004 that said the entering zones is a chronological array of the zones the object passed through. And that the logic should be to look for the desired source zone in the before entered zones and then look for the next zone in the after entering zone. before and after entering zones are both arrays and at least in some cases identical arrays? I think I am probably seeing posts related to an older version of frigate. Can you please re-explain how to track objects from one zone to the next. My use case it the typical street - > driveway ( arrival ) test. I do not care about departures ( driveway -> street ) at this time.

[inkeep-ai-assistant[bot]]

You're correct that zone tracking has evolved. Here's how to track objects moving between zones in current versions of Frigate:

Zone Presence Basics

Zones evaluate object presence based on the bottom center of the bounding box(1). An object is considered present in a zone when this point falls within the zone coordinates(1).

Tracking Movement Between Zones

For your street → driveway arrival scenario, the recommended approach uses MQTT events to check zone transitions(2)(3):

Check these conditions:

• before.entered_zones should NOT contain "driveway"
• after.current_zones should contain "driveway"(2)

This logic detects when an object first enters the driveway zone, regardless of which zone it came from(2)(3).

Understanding Zone Fields

The MQTT event payload includes(4):

• entered_zones - tracks which zones the object has entered during its lifecycle
• current_zones - shows which zone(s) the object is currently in

Important note: With stationary object detection, entered_zones reflects the original order from when the object was first detected and doesn't update dynamically when the object moves again(2). The current_zones field updates in real-time(2).

Avoiding Multiple Triggers

To prevent repeated notifications while the object remains in the zone, check that before.entered_zones doesn't already include your target zone(3). This ensures you only trigger once when the object first enters(3).

Zone Inertia

By default, an object must be present in a zone for 3 consecutive frames before being considered in that zone(1)(5). You can adjust this with the inertia setting if needed(1)(5).

For your arrival detection, focus on monitoring current_zones changes rather than relying solely on entered_zones ordering(2)(3).

📚 Sources:

1. Zones
2. Tracking crossing zone with stationary objects detection
3. [Support]: After upgrading to Frigate 0.13 "new" MQTT events do not have zones
4. MQTT
5. Full Reference Config

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