Measure room occupancy with a crowding alert

Cover a floor with a zone, read how many people were inside at once and for how long, and record an event whenever the area gets crowded.

Time: 15 minutes
You need: The corridor sample video
Pages of the app: Scene Builder, Experiments, Data
Topics: Occupancy and dwell

What you will be able to do

Draw a zone that follows the floor
Read occupancy, visits and occupied time
Flag crowding with an occupancy limit
Find flagged moments in the event list

A zone counts the objects inside it at every moment. That gives the occupancy of a room, a shop floor or a platform. With Flag occupancy above, CV-Scope also records an event each time the area gets more crowded than you allow.

Step 1. Draw the floor zone

Open the Scene Builder of the Corridor camera. If it does not exist yet, add it as in guide 02.
Click New experiment, name it Floor occupancy, keep Person and click Create experiment.
Press Z. Click the four corners of the wooden floor:
- where the back wall meets the floor at the far left,
- the same at the far right,
- the bottom-right corner of the picture,
- the bottom-left corner of the picture.
Double-click the last corner to finish.
In the inspector, set these fields:
- Name: Floor.
- Measure: keep all four boxes ticked.
- Ignore visits shorter than: 1 second. A person found for a moment is then not counted.
- Flag occupancy above: 2. A third person on the floor creates an Occupancy exceeded event.
Click Save in the top bar, or press Ctrl+S.

Step 2. Run it

Click Start. During the run, the bottom bar counts Floor entries and Floor exits.
When the clip has finished, click Results at the bottom of the Scene Builder.

Step 3. Read the occupancy

The Zones (occupancy and dwell) panel shows these values for Floor:

Column	Meaning	Sample result
Occupied time	Time with at least one person on the floor	about 19 s
Total time, all objects	All visits added up	about 34 s
Visits	Completed visits	7
Mean visit	Average time a person stayed	about 4.8 s
Longest visit	The longest stay	about 5.8 s
Max occupancy	Most people on the floor at the same time	3

Occupied time is shorter than total time because people overlapped. At about 00:30, three people cross the floor together.

Step 4. Find the crowded moments

Open the Events tab of the results.
Set Event type to Occupancy exceeded.
Each row is a moment when more people than the limit were inside. Click a row and then Jump to video to see it.

The sample has one such event, at about 00:30, when the three people arrive together. A new event is recorded only after the occupancy has dropped back to the limit.

For a real room

See the whole floor. People outside the zone are not counted, so the camera must see all of it. A camera high in a corner works well.
Count people only once. A zone counts each tracked person. If people are hidden behind each other, the occupancy is too low. Mount the camera higher.
Long recordings. For a live camera, occupied time is also split by clock hour below the zones table.

Guide 10 measures how long each person waits in an area, with a rule for long waits.