Setting the Camera Height and Lens Size in Software
The VT Setup software assumes that you have a 3.6 mm lens and the camera is mounted at a height of 3 m above the floor. If this is not correct then you need to change this setting in VT Setup. Do this before altering anything else like the counting zone size and position. This is because changing the lens or camera height alters the size of the counting zone and the size of a person in the picture.
- If you haven't yet done so, in the VT Setup software connect to a site in the Unit Select tab.
- Go to the Logger Setup tab and choose the controlling Logger from the Unit Address list.
- Select the VT setup tab. More tabs appear.
- Identify the VT unit that is connected to the camera, and choose its address in the Select VT tab. (To check you have the correct VT module, click the "Flash Up/Down on this VT" button. The module's count lights will flash three times.)
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Click the Tune button. The software reads the VT module's settings, which might take a few moments. When you do this the selected VT unit stops counting and its count lights flash.
- Enter the correct lens size and the height of the camera above the floor. VT Setup changes its other settings - counting zone position, people size, and so on - to suit the new camera entries. Some of the new settings are shown in the Suggested grid. You can edit these here if you wish.
- Click the Apply to VT button.
Note: You can also set the camera height and lens size in the Camera/Video Out tab.
If you find that people are not being counted you could change the camera setting to a greater distance, which will in effect increase the sensitivity. Double-counting indicates that a nearer setting would be better. See also the Fault Finding section.
This table shows the default zone widths for different lenses and camera heights. You can change these zone widths by up to 25% using the VT Setup software.
| Focal Length > | 2.9 mm | 3.6 mm | 4.6 mm | 6.0 mm | 8.0 mm |
| Height | |||||
| 2 m | 1.66 m | ||||
| 2.5 m | 2.07 m | 1.67 m | |||
| 3 m | 2.48 m | 2.00 m | 1.57 m | ||
| 3.5 m | 2.90 m | 2.33 m | 1.83 m | ||
| 4 m | 2.67 m | 2.09 m | 1.60 m | ||
| 4.5 m | 3.00 m | 2.35 m | 1.80 m | ||
| 5 m | 2.61 m | 2.00 m | 1.50 m | ||
| 5.5 m | 2.20 m | 1.65 m | |||
| 6 m | 2.40 m | 1.80 m | |||
| 6.5 m | 2.60 m | 1.95 m | |||
| 7 m | 2.10 m | ||||
| 7.5 m | 2.25 m | ||||
| 8 m | 2.40 m |