UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
4-15.4.1 On-site and hard-wired cameras
4-15.4.2 Off-site image transmission cameras.
4-15.5
Bandwidth is not as big an issue for on-site cameras because generally the
cameras are hardwired (copper or fiber) and the distances are shorter. It is relatively
easy to increase bandwidth by adding conductors. Off-site cameras, on the other hand,
are more costly to add because the camera images have to be transmitted over
conductors (typically leased) that cross property lines.
4-15.5.1 One technique for conserving bandwidth from off-site remote cameras to a
Dispatch Center is to locate the DVR(s) at the remote facility. Information can be
downloaded to a DVR local to the remote location at a high resolution and frame rate. If
a video motion or other alarm event occurs (such as a door contact alarm), information
can be transmitted to the Dispatch Center for review. This technique of only transmitting
video images back to the Dispatch Center when an alarm occurs conserves bandwidth
and relieves the Dispatch Center personnel of continually watching monitors.
4-15.5.2 Another advantage of placing the DVR at the remote site is that if
communications are lost between the remote site and the Dispatch Center, camera
image archives are still available at the DVR at the remote site. The downside to this
configuration is that constant non-alarm camera images are not available at the
Dispatch Center.
4-16
WHITE BALANCE
4-16.1
White balance is the ratio of black to white on a CCTV camera image. Most
cameras (80%) are supplied with automatic white balance. Auto white balance ought to
be used when the camera background image is changing. While it is possible to procure
cameras with manual black-white balance, this should only be done in a very stable
black-white image environment.
4-17
CCTV CAMERA EMPLOYMENT FOR INTRUSION DETECTION
4-17.1
Background. Originally, cameras were employed for intrusion detection by
allowing an operator to continually view images on display screens. Intrusion detection
occurred by human recognition of an intrusion event. Issues of operator fatigue,
distractions and number of monitors that can be effectively observed left a lot of room
for missing an intrusion event. While camera technology has not changed significantly in
the last decade, the introduction of digital images and software programming capability
has improved significantly. So while the camera housing, the lens, focal length and
associated image are basically the same, the ability to digitally process the digital image
in a manner that allows automated intrusion detection has seen a tremendous increase
in technology in the last ten years. Programming trip wires can allow automated alarm
notification with no prior human involvement. Methods for detecting intruders by CCTV
systems include video motion detection, video content analysis, and motion path
analysis.
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