Line & Zone Placement

Most of the register types will have a corresponding virtual count line or zone that must be configured within the available field of view.

The key consideration when positioning and shaping lines and zones is that people who you want to count will definitely cross the line, or enter that zone. Do not worry too much about people who you do not want to count crossing that line or entering that zone at this stage, as additional configuration options are available to stop unwanted counts. 

 

Lines

The below example illustrates the golden rules for all line types that should be followed.

Firstly, no part of the line should be outside the active part of the field of view. Remember that the video view is larger than the time of flight view.

This is incorrect:

Here, the problem is that the lines stretch well outside the active time of flight field of view.

By switching to Edit Mode the time of flight field of view can be more clearly seen:

Remember that the video view is larger so that users can see what gong on more easily.

In Edit Mode, Lines can now be moved to their correct position. The line can be clicked and dragged.

The larger circles are pivot points and can also be dragged individually, while the smaller circles can be clicked to create a new pivot point. Double clicking a pivot point removes that point.

Flip back and forth between Edit and Video view mode in order to fine tune the line positions:

Note that the ends of the lines meet the edges of the door, but importantly, at the floor level.

Line ends should be positioned in positions within the field of view corresponding to the edges of the doorway.

Importantly no one should be able to walk around the ends of the lines and hence not be counted.
Importantly lines must be placed on the ground.

Moving on from this, it is also very important that the Vector has enough time to recognise a person and start tracking them (indicated by a yellow or red target being overlaid in a position corresponding roughly to the persons feet).

Essentially a person must be seen as a person and a target generated before they cross the line.

If a person is recognised as a person and assigned a target only after they have already crossed the count line then it is too late and a corresponding count increment will not be given. This is an under count and implies that the lines are not positioned optimally.

Importantly lines need to be positioned away from the edge of the field of view that a person will enter fromm so as to allow enough time for a target to be assigned and seen crossing the line. 

Again switching to Edit mode allows additional 'pivot points' to be added. These can then be moved to create a larger distance from the door whilst leaving the ends in the same position at the door sides to prevent circumnavigation.

Whenever you are wanting to do any kind of height filtering on targets - to separate adults from children, or to ignore trollies, baggage or some other non human item - it is important to remember that the centre part of the field of view shows where height measurement is possible.

Because of the angles involved and simple trigonometry, when anyone walks at the edges of the field of view, only the lower part of their body (feet upwards) will be seen in the field of view. As they get closer to the centre of the field of view more of the person is seen until their head is well inside and height measurement can be accomplished.

This means it is important for the count lines to intersect the height measurement area in the centre of the field of view when using height filtering (by Global Height Filtering, or by Register based filtering).

 

Alignment Tools

To ensure that lines and zones are placed correctly there are a number of alignment functions provided when in Edit mode.

Two extra buttons will be shown. The first one allows you to position a line or zone in exactly the same place as another line or zone. It does not change any of the associated underlying settings (height filtering for example), just the position within the field of view.

This is typically used to ensure that an IN and an OUT line are set the same with only their direction being different/opposite. But it can be used to position multiple IN and OUT lines with (for example) different height filtering enabled (adult and child counting) all in exactly the same place.

The second button allows you to flip the direction of a line. This will typically be required after positioning an OUT line to the same location as an IN line using the first button. Copying settings in that way will mean both lines will be counting in the same direction so flipping one of them will leave both lines in the same place but with opposite direction counting.

For further guidance on how to align lines and zones see here.