Swann 8 Channel DVR H.264 - Manual (Page 30)

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How Motion Detection Works
The way that the DVR looks for motion is quite straight forward - it’s a process where
it compares one frame (that is, a single image taken approximately a 25th/30th of
a second from the previous image) with the next. A certain amount of “difference”
between these two “frames” is interpreted as motion.
As a result, the DVR is able to detect when there is a change in the picture. However,
this does not necessarily need to be something moving in the frame. For example, a
light being turned on or off, a lightning flash or even the sun coming out momentarily
on a cloudy day might be enough to trigger the motion detection on the DVR.
However, as these events last only a moment (and are relatively rare) they will only
create a few very short redundant clips, which will not take up too much space or
pose a problem with scanning through footage.
This method of motion detection can, however, become problematic when using
wireless cameras. As wireless technology is susceptible to interference, the static and
image distortion common to wireless systems is often enough to trigger the motion
detection inadvertently.
As a result, we strongly advise against using wireless cameras with any of
our motion sensitive recording equipment, and advise the use of hard wired
cameras. If you simply must use wireless technology, we advise using digital wireless
technology as this technology is much more resistant to interference from other
wireless equipment and environmental causes. However, any wireless technology,
digital or otherwise, has serious limitations when combined with motion detection.
For a similar reason, don’t use PTZ systems and motion detection simultaneously.
The DVR will interpret the camera moving as ‘motion’ and record. This is particularly
true when using Cruise Mode - as the camera is moving almost continually, so too is
the DVR recording almost continually!
Notes
• Wireless cameras are not recommended for use with the motion detection.
• Motion detection is not recommended for use with PTZ systems. Avoid enabling
motion detection on a channel which has a PTZ system attached to it - especially
when the PTZ system is set to Cruise Mode.
• Setting the motion detection at high sensitivity levels (5 or higher) increases the
frequency of false alarms. On the other hand, low sensitivity levels (4 or lower)
increase the risk that a significant motion event (such as an intruder) will not trigger
the motion detection to record.
• Check the Motion Detection settings both during the day and at night. In low-
light conditions (or when your cameras are using infrared night vision) the DVR may
be more or less sensitive to motion, depending on your unique circumstances. The
difference might be very dramatic!
About Motion Detection