Positioning Cameras Over Single Doors
For an entrance the width of a single door, consider these factors when siting the camera.
Does the door open into the zone detected by the Video Turnstile
counters? If so it is important that the door does not completely cross
the counting zone. You should therefore mount the camera some
distance inside from the door frame: typically 0.5 to
1 metre.
Note: to see the counting zone markers, conect the Video Turnstile counter module to a TV monitor, a hand-held PC or a frame grabber.- The counting zone should be reasonably
well illuminated so that a good video
picture can be provided by the camera. You
should also consider the lighting changes when:
- The door opens. This may mean additional illumination from outside areas, or changes in reflected light according to door position.
- A person enters or leaves through the door. The person may block out sources of normal illumination, or reflect additional light back to the camera. A shadow may also be associated with the person crossing the zone. The detection unit will normally cope with changes to ambient light levels associated with people crossing the zone. However shadows preceding, following or to the side of people, may cause additional counts.
- If you haven't already done so, check your lens focal length and measure the distance between the camera and the floor.
- Use the VT Setup software to fine tune the system.