Bosch VG4-200 User Manual page 106

VG4 Modular Camera System
Global change
You can set how large the global change in the video image must be for an alarm to be
triggered. This setting is independent of the sensor fields selected under Select Area. Set a
high value if fewer sensor fields need to change to trigger an alarm. With a low value, it is
necessary for changes to occur simultaneously in a large number of sensor fields to trigger an
alarm.
This option allows you to detect, independently of motion alarms, manipulation of the
orientation or location of a camera resulting from turning the camera mount bracket, for
instance.
Global change
Activate this function if the global change, as set with the Global change slide control, should
trigger an alarm.
Scene too bright
Activate this function if tampering associated with exposure to extreme light (for instance,
shining a flashlight directly on the lens) should trigger an alarm. The average brightness of the
scene provides a basis for recognition.
Scene too dark
Activate this function if tampering associated with covering the lens (for instance, by spraying
paint on it) should trigger an alarm. The average brightness of the scene provides a basis for
recognition.
Scene too noisy
Activate this function if tampering associated with EMC interference (noisy scene as the result
of a strong interference signal in the vicinity of the video lines), as an example, should trigger
an alarm.
Reference check
You can save a reference image that is continuously compared with the current video image. If
the current video image in the marked areas differs from the reference image, an alarm is
triggered. This allows you to detect tampering that would otherwise not be detected, for
example if the camera is turned.
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Disappearing edges
The area selected in the reference image should contain a prominent structure. If this
structure is concealed or moved, the reference check triggers an alarm. If the selected area is
too homogenous, so that concealing and moving the structure would not trigger an alarm,
then an alarm is triggered immediately to indicate the inadequate reference image.
Appearing edges
Select this option if the selected area of the reference image includes a largely homogenous
surface. If structures appear in this area, then an alarm is triggered.
Bosch Security Systems, Inc.
Click Reference to save the currently visible video image as a reference.
Click Select Area and select the areas in the reference image that are to be monitored.
Check the box Reference check to activate on-going matching. The stored reference
image is displayed in black and white below the current video image, and the selected
areas are marked in yellow.
Select the Disappearing edges or Appearing edges option to specify the reference check
once again.
User's Manual
Configuring the IP AutoDome | en 105
F.01U.133.268 | 6.0 | 2010.03