LevelOne FCS-7111 - Manual (Page 70)

70 - User's Manual
A green bar indicates that even though motions have been detected, the event has not been triggered
because the image variations still fall under the defi ned threshold.
NOTE
► How does motion detection work?
There are two motion detection parameters: Sensitivity and Percentage. In the illustration above,
frame A and frame B are two sequential images. Pixel differences between the two frames are
detected and highlighted in gray (frame C) and will be compared with the sensitivity setting. Sensitivity
is a value that expresses the sensitivity to moving objects. Higher sensitivity settings are expected to
detect slight movements while smaller sensitivity settings will neglect them. When the sensitivity is set
to 70%, the video server defi nes the pixels in the purple areas as “alerted pixels” (frame D).
Percentage is a value that expresses the proportion of “alerted pixels” to all pixels in the motion
detection window. In this case, 50% of pixels are identifi ed as “alerted pixels”. When the percentage is
set to 30%, the motions are judged to exceed the defi ned threshold; therefore, the motion window will
be outlined in red.
For applications that require a high level of security management, it is suggested to use higher
sensitivity settings and smaller percentage values.