UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
4-10.3.6 A number of illuminator manufacturers each produce a variety of beam
patterns. For example 10 and 30 spot (precise) illuminators and 60 flood illuminators.
4-10.4
Thermal Imagers. Thermal imagers use a special technology that senses
heat signatures rather than visual information. These cameras operate under complete
darkness. Thermal imagers are best used in long-range detection and surveillance
applications. Thermal imagers detect and display images based on infrared light
emitted from objects rather than visible light reflected off objects. The most common
technology is Forward Looking Infrared (FLIR). Thermal cameras work on a
temperature differential between the object and the background. In desert
environments, the background is white and people are black. In cooler environments,
the background is black and people are shown as white images. A key advantage of
long-range thermal imagers is that they are less susceptible to environmental influences
from rain and fog. The disadvantage of thermal-imagers is the high cost. Typically
thermal imagers are classified as medium or long wavelength as illustrated in Table 4-4.
Table 4-4. Characteristics of Thermal Imagers
Classification
Cooling
Cost
Recommended
Service Period
3- 5 micron
Cryogenically
0K
7500 hours
Medium
meters
cooled.
7-14 micron
Uncooled
K
30,000 hours
Long
meters
4-11
POWER
4-11.1
Options for CCTV power include 12 Vdc, 24 Vdc, 24 VAC, and 120 VAC. As
with any power system, it is important to understand voltage drop limitations, current
draw issues, grounding, and battery or uninterruptable power supply (UPS) backup.
Exterior camera are typically powered by 120 VAC because additional power is needed
for heating and controls (pan, tilt, zoom). 12 Vdc and 24 Vdc cameras are easier to
provide backup power with through batteries. Power systems are further described in
Chapter 9, "General Requirements and Cross-Discipline Coordination."
4-12
CAMERA FIELDS-OF-VIEW
4-12.1
An important consideration when designing a camera system is determining
the field-of-view for each camera. The camera field-of-view affects the lens, zoom level,
and number of cameras needed.
4-12.2
For cameras used to detect an intruder (with the capability to determine the
presence of an intruder but not necessarily classify the intruder as a human, animal or
object), the area of interest should occupy a minimum of 10 percent of the field-of-view,
with a maximum field-of-view of 300 feet in length or less.
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