Xtralis ADPRO Presidium, Installation And User Manual

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Installation and User Manual ADPRO Presidium by Xtralis
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2. Camera Field of View (FOV)
Setting the correct horizontal FOV of the camera is critical for reliable detection. The horizontal
FOV determines the lens required on the camera. The following guidelines are important:
• Ensure there is adequate detection area. The minimum detection area requirement is 6m
(19ft) width, i.e. if there is only a 2m (6ft) gap between a building and a fence, then reliable
detection will not be possible.
• Ensure that the horizontal FOV at the maximum detection range does not exceed the
recommended maximum of 25m (82ft).
• The tilt of the camera should be such that the FOV does not include large areas of the sky,
thereby reducing the detection area of the Presidium
system.
• Ensure the FOV is clear, with minimum views of foliage and obstructions that provide cover
for intruders.
• Presidium uses perspective compensation for its motion detection algorithms, hence it is
important that the FOV is not obtuse, i.e. a target in the background on the left edge of the
FOV must be the same size as a target on the right edge of the FOV.
• When designing cameras to look along a fenceline, the majority of the horizontal FOV of the
camera should be on the monitored side of the fence.
3. Camera and Lens Selection
The maximum horizontal field of view and the likely target size to be detected, determines the
required camera and lens configuration. The absolute maximum horizontal field of view where
detection occurs should not be more than 30m (98ft).
Presidium functions most effectively when the camera is not mounted too high. The perspective
characteristics used in the detection algorithms will not function as expected when the camera is
mounted too high. When looking directly down on a cat or a person, their relative sizes are quite
similar, the true sizes can be judged only when viewing at an angle. Place the camera at a height
that it is out of reach of intruders. This should be between 3 - 6 metres (9.8 - 19.7ft). The ideal
height is 4.2m (14ft), as this allows the detection algorithms to function and is high enough to
prevent tampering with the camera.
Analysis of the site plans and information from the site survey determine the FOV of the camera
to ensure coverage of all areas requiring protection. Always ensure that the maximum horizontal
FOV is no greater than 25m (82ft), to avoid compromising detection of small targets.
The tables in Appendix E show the approximate maximum distance between the camera and the
target for reliable detection, at a maximum horizontal field of view of 20m (66ft), 22m (75ft) and
25m (82ft) respectively. The approximate dead zone beneath the camera is also shown, for a
camera mounted at 4.2m (14ft), although this will vary depending upon the final angle at which
the camera is set. These figures should be used for guidance only. Other considerations, such as
lighting and external environmental aspects, may dictate the use of different camera/lens
combinations.
The formula for determining the distance from camera to target based upon the maximum
horizontal FOV is as follows:
(Lens focal length) x (Maximum horizontal field of view)
Distance between camera and target = ____________________________________________
(Camera format width)
Where: Distance between the camera and target is in metres.
Maximum horizontal field of view is in metres
Lens focal length is in millimetres
Camera format in millimetres =
8.8 mm for a 2/3" camera.
6.4 mm for a 1/2" camera.
4.4 mm for a 1/3" camera.
3.2 mm for a 1/4" camera.