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SCENE MANAGEMENT
Areas Where Movement is Permitted
Areas within a scene where movement may legitimately occur
must he free of Detection Zones to prevent the DuoTect-C
from alarming unnecessarily. Remove branches of trees and
other plant material close to the camera. If the camera is
mounted in a particularly inaccessible position (such as high
on a roof), ensure that a plant or tree cannot grow into the
picture. This could happen over a period of several months
and will result in nuisance alarms.
Avoid scenes which include:
wind.
can reflect images of clouds, cars, or other moving objects
normally outside of the target area.
scenes.
Some camera types cannot produce a stable video output. This
will be particularly evident at a high contrast black and white
edge in a scene. If this effect is noticed, then the cells sending
this edge are best removed.
Reflections:
Window glass, car body surfaces, and other
reflective surfaces may cause problems by reflecting the
puddles of water. The fitting of polarizing filters on the
camera helps prevent this from occurring. Alternatively,
remove the cells from the scene. If car headlights are a
nuisance, fence off the area of concern with opaque fencing.
Detection Zone Pattern
A full Detection Zone pattern contains 896 (AD1562 NTSC
model) or 1024 (AD1562X PAL model) detection cells. These
are intended to cover the usable portion of the video image
(see below). However, most monitors tend to overscan to
some degree, and this tends to push cells outside of the viewed
area. This can be the cause of apparently inexplicable alarms.
F i l l e d D e t e c t i o n Z o n e
The full Detection Zone pattern, set by AD1562 system
default, covers only the usable portion of the monitor video
image. This does not cover the complete scan area of the
monitor. since the edges of the scan area arc not usable for
detecting motion. The illustration above shows the relation of
the default Detection Zone (the white area) as compared with
the monitor scan area (the grey area outside of the white).
(The white and grey relationship indicated above is reversed
during certain zone editing functions, see pages 9 and 11.)
Monitor Setup:
Since monitors may not view all of the
detection areas, due to overscan as stated above, use a full
Detection Zone pattern (set by the system defaults) to adjust
the monitor vertical and horizontal size so that all cells are
viewed on the monitor screen. A full Detection Zone pattern
displays all detection cells that cover the usable video image.
Use the horizontal and vertical hold adjustments of the monitor
to ascertain that all cells are removed from outside of the
desired viewing area.
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