Count people in and out of a door

A gate is a counting line that also works as the start or end of a route. Put one across a doorway and CV-Scope separates the people who come in from the people who go out.

The corridor clip has a doorway on the left. This guide counts the people who use it.

Step 1. Draw a gate in front of the door

1. Open Cameras, select Corridor and click Open scene builder. If the camera does not exist yet, add it as in guide 02.
2. Press G, or click Gate in the tool column.
3. Click on the floor at the foot of the back wall, about a sixth of the way in from the left edge. Then click at the bottom edge of the picture, straight below.
4. In the inspector, set Name to Door and keep Person ticked under Object to track.
5. Look at the solid arrow on the gate. It should point left, towards the door and out of the room. If it points into the room, click Flip forward direction.
6. Click Save in the top bar, or press Ctrl+S.

Forward now means out of the room, and reverse means into the room.

Step 2. Name the two directions

Rules turn the two directions into words. The words then appear in the counters during a run and in the exported data.

1. Click New experiment in the top bar. Set Name to Door counts, keep Person, and click Create experiment.
2. Click Edit experiment in the top bar. The experiment page opens.
3. In the Rules panel, click Add rule. Keep Single trigger and set the rule like this:
   • WHEN: Person.
   • CROSSES: Door, and forward in the direction list.
   • COUNT AS: Out.
4. Click Add rule again and set the second rule the same way, with reverse and In.
5. Click Save at the top of the page.

Step 3. Run it

1. Click Start at the top of the experiment page.
2. While it runs, open Live to see the run with its counters, including Out and In.
3. When the run has finished, find it under Runs on the experiment page and click Results.

Step 4. Read the counts

• Line crossings shows Door with Forward for people going out and Reverse for people coming in.
• Events by type shows Rule events, one for each named crossing.
• On the Events tab, the Route / label column shows Out or In for each rule event. The CSV export has the same labels.

With the recommended detector the sample shows 4 crossings, all forward. Four people left through the door during the clip and nobody came in.

Set up a real door

• Camera position. Mount the camera high and looking down at the doorway. Seen from above, people do not hide each other while they pass.
• Gate position. Draw the gate across the floor just inside the door, where everyone has to pass. Make it a little wider than the doorway.
• Frame rate. A person must be seen on both sides of the gate. On the experiment page, under Advanced settings, keep Processing FPS at 10 or more for a door that people walk through quickly.
• People inside. Since the start of the run, the people inside are In minus Out, if the room was empty at the start. To count the people in a room directly, use a zone, as in guide 09.
• Live runs. A run on a live camera continues until you click Stop.

A door the camera cannot see through

Often the camera sees only one side of the door: a hall or landing with the doors of the rooms around it. Someone walking into a room is hidden by the door frame before their feet reach a line drawn at the door, and nobody is ever seen on the far side. A plain line then counts nobody.

1. Draw the line along the door frame on the floor, as far as the feet go before the person disappears. Make it a little longer than the opening.
2. Point the solid arrow into the room (Flip forward direction if not).
3. In the inspector, under Doorway, tick The camera cannot see past this line. The line’s label on the canvas now ends in (doorway).

A person who walks up to the line and disappears there now counts as a forward crossing, and a person who appears there and walks away counts as a reverse crossing. The crossing is counted when the tracker gives the person up, a few seconds after they vanished, and is dated when they were last seen. On the Events tab its direction reads forward (doorway).

Where people come into view right next to a line (for example out of a room under the camera), their first boxes can be only an arm or a torso. Raise Minimum track age under Advanced on that line to 4 so those first boxes cannot cross it.

Next

Guide 06 watches a pet instead of people. Guide 07 counts people, bicycles and cars separately.