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Cameras
Closed-circuit television (CCTV) is the use
of video cameras to transmit a signal to a specific place, on a limited set of
monitors.
It differs from broadcast television in that the signal is not openly
transmitted, though it may employ point to point (P2P), point to multipoint, or
mesh wireless links. Though almost all video cameras fit this definition, the
term is most often applied to those used for surveillance in areas that may need
monitoring such as banks, casinos, airports, military installations, and
convenience stores. Video telephony is seldom called "CCTV" but the use of video
in distance education, where it is an important tool, is often so called.
In industrial plants, CCTV equipment may be used to observe parts of a process
from a central control room, for example when the environment is not suitable
for humans. CCTV systems may operate continuously or only as required to monitor
a particular event. A more advanced form of CCTV, utilizing Digital Video
Recorders (DVRs), provides recording for possibly many years, with a variety of
quality and performance options and extra features (such as motion-detection and
email alerts). More recently, decentralized IP-based CCTV cameras, some equipped
with mega pixel sensors, support recording directly to network-attached storage
devices, or internal flash for completely stand-alone operation.
Surveillance of the public using CCTV is particularly common in the United
Kingdom, where there are reportedly more cameras per person than in any other
country in the world. There and elsewhere, its increasing use has triggered a
debate about security versus privacy.
A growing branch in CCTV is internet
protocol cameras (IP cameras). IP cameras use the Internet Protocol (IP) used by
most Local Area Networks (LANs) to transmit video across data networks in
digital form. IP can optionally be transmitted across the public internet,
allowing users to view their camera's through any internet connection available
through a computer or a 3G phone. For professional or public infrastructure
security applications. IP video is restricted to within a private network or
VPN.
Many consumers are turning to wireless
security cameras for home surveillance also. Wireless cameras do not require a
video cable for video/audio transmission, simply a cable for power. Wireless
cameras are also easy and inexpensive to install. Previous generations of
wireless security cameras relied on analog technology; modern wireless cameras
use digital technology which delivers crisper audio, sharper video, and a secure
and interference-free signal.
Unless physically protected, CCTV cameras have been found to be vulnerable
against a variety of (mostly illegal) tactics.
Some people will deliberately destroy cameras. Some cameras can come with
Dust-Tight, Pressurized, Explosion proof, and bullet-resistant housings.
Spraying substances over the lens can make the image too blurry to be read.
Lasers can blind or damage them. However, since most lasers are monochromatic,
color filters can reduce the effect of laser pointers. However, filters will
also impair image quality and overall light sensitivity of cameras (see laser
safety article for details on issues with filters). Also, complete protection
from infrared, red, green, blue and UV lasers would require use of completely
black filters, rendering the camera useless.
Key Benefits
- Benefit 1: Crime prevention
- Benefit 2: Traffic monitoring
- Benefit 3: Industrial processes
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JESCO
ELECTRIC CO
