UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
4-6.3.7 Always use sturdy mounting equipment to avoid vibrations caused by strong
wind. This is especially important with a long focal length lens. These lenses amplify
even the smallest movement of the mount. Building mounts are generally more stable
than pole mounts. When in extremely windy conditions for a critical camera, consider
using a gyro-stabilized mount lens to avoid vibration caused by wind. The gyro-
stabilized lens has a cost premium and is not appropriate for general applications.
4-6.4
Fixed Position Cameras. Fixed position cameras are mounted in a fixed
position and cannot rotate or pan. A good application for fixed cameras is detection
surveillance, because video motion detection can be more readily applied to the static
field-of-view. The installation and cost of fixed cameras is lower because there is no
associated motor/control wiring. Fixed cameras are good for review of pre-alarm
conditions because there is a static view of the alarm area. Pre-alarm allows the review
of video information for the time period (typically ten to fifteen seconds) immediately
before the alarm occurred. Due to the static view, fixed cameras are not as well suited
for tracking a dynamic event.
4-6.5
Pan/Tilt/Zoom (PTZ) Cameras. PTZ camera mounts allow the camera to
rotate, pan, tilt, and zoom. Because of the drive motor, housing, and wiring for controls,
PTZ cameras are typically three to four times more expensive than fixed cameras.
However, the operator gets a much better view of the overall area than with a fixed
camera. PTZ cameras are often used for assessment surveillance applications to view
and assess alarm conditions. PTZ cameras are not well-suited for pre-alarm
assessment because they may not be focused on the alarm area at all times. When
designing CCTV surveillance, consideration needs to be given to lost coverage within
the camera sweep field-of-view when the camera zooms to a fixed location. Refer to
Figure 4-8.
4-6.5.1
There are three modes in which PTZ cameras can be employed:
4-6.5.1.1 Default at home and zoom to alarm.
4-6.5.1.2 Continually sweep
4-6.5.1.3 Manual control
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