Bosch VIDEOJET X20 - Manual (Page 67)

VideoJet X20 Configuration Using a Web Browser | en 67
Bosch Security Systems Installation and Operating Manual V3.5 | 2007.12
5.23.9 Trigger delay (s)
You can set delayed alarm triggering. The alarm is only triggered after a set time interval in
seconds has elapsed and then only if the triggering condition still exists. If the original
condition has been restored before this time interval elapses, the alarm is not triggered. This
allows you to avoid false alarms triggered by short-term changes, for example cleaning
activities in the direct field of vision of the camera.
5.23.10 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.
5.23.11 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.
5.23.12 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.
5.23.13 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.
5.23.14 Global change
Activate this function if the global change, as set with the Global change slide control, should
trigger an alarm.
5.23.15 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.
1. Click Reference to save the currently visible video image as a reference.
2. Click Select area and select the areas in the reference image that are to be monitored.
3. Check the Reference check box 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.