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Home > How IP-based video surveillance works -- way beyond analog CCTV
March 23, 2005
By: Lori Wilkerson
When you’re shopping around for an IP-based video
surveillance system, you will need to be particularly
cautious about what exactly you’re looking at and what the
individual terms mean. How IP-based video surveillance works
is open to interpretation as far as some video surveillance
and security salespeople are concerned -- not because they
are trying to confuse the issues, but because there is no
genuine consensus on what the term “IP-based” or related
ones such as “networked” or “web-based” means.
Originally video surveillance was done based on analog
technology -- closed circuit television (CCTV) and recording
on video tapes. This was fine for recording what was going
on, but it didn’t broadcast actual live information, so it
wasn’t practical for monitoring stores, for instance, from a
remote location. It simply provided what happened after the
fact. The picture quality wasn’t great and it relied on
human reliability as well -- someone had to remember to
change the tapes regularly, etc.
Digital revolutionizes video surveillance
With the Internet revolution and the ever-increasing
presence of Local Area Networks, technology took great
strides in video surveillance in the 1990’s. Analog camera
tubes were replaced with CCD (Charged Coupled Devices) and
digital cameras became affordable for most people.
This combination meant that video surveillance could do
two things: go live over the Internet or a closed network
for surveillance and provide clearer, crisper images that
could be tracked and manipulated easily. For law
enforcement, digital surveillance meant it was much easier
to zoom in on images, track particular scenes and enhance
features.
The basics of IP-based surveillance
A digital camera “views” the scene in front of it,
broadcasts the video images as a digitized signal over a LAN
line (Local Area Network) where it’s then transmitted to a
computer or server. The server in turn manages all of this
information. Depending upon the software used to manage the
digital images, it can record, display or retransmit the
images to anywhere in the world.
The software package can easily be upgraded to allow for
analyzing data, selecting specific “flagged” items to watch
for and a host of other functions, making it a truly
customizable security tool.
True IP-based digital surveillance uses CCD cameras that
use signal processing that send packetized video streams
over the LAN through a Cat 5 cable rather than a coax cable
network, utilizing greater bandwidth and standard TCP/IP
communication.
It also provides more intelligent data mining and
information retrieval. If security is an issue, full digital
surveillance also offers the added advantage of data
encryption opportunities to protect against image tampering
-- something not possible with analog recording.
Recently, a few companies such as D-Link and Linksys have
also developed fully digital cameras that actually have
completely integrated, built-in web servers so that no
external computers are needed for operating them. The signal
is transmitted directly to the terminal location for storage
or play-back.
Halfway there…
The “middle of the road” of video surveillance is
upgrading video surveillance by utilizing a Digital Video
Recorder (DVR). A DVR system is not really fully IP-based,
but is step toward the more advanced IP technology. In
actuality, a DVR system uses the same camera and structures
for cabling as the older CCTV analog systems, but the old
VCRs have been replaced with DVR for storage of the data.
The data is converted to digital so that it can be stored on
hard disks, but the quality of the images captured remains
analog since this is how it originated.
When shopping for a system, be sure to ask if the system
is digital based on the recording (DVR) or on the camera,
since many manufacturers consider a system digital by virtue
of the DVR storage system even if the camera recording the
images is still analog.
Going all the way
Some people will move to the hybrid models of a CCTV/DVR
system when they first move beyond an analog system because
it seems like the next practical evolutionary step in video
surveillance. However, shifting to this method largely
ignores how IP-based video surveillance works.
With CCTV/DVR surveillance you have actually simply
delayed the inevitable by adding on a relatively new
technology (hard disk, digital storage) to an old technology
(analog video over coaxial transmission lines). Rather than
moving forward into something new, you have prolonged the
demise of the old.
Advantages of IP-based video surveillance
The leap into completely IP-based technology is the best
bang for your buck both monetarily and in terms of security
by far. Digital surveillance can be done over a LAN network,
of course, but TCP/IP transmittal of surveillance makes
sense for remote monitoring of multiple locations and for
remote recording of data onto back-up servers and hard disks
for long-term storage.
With IP-based video surveillance, you can connect your
surveillance camera or cameras to any network or wireless
adapter, and you are extremely flexible in your placement of
the camera itself. A typical PC-attached video camera, while
providing digital picture image quality, still has to be
within approximately ten feet of the computer itself.
Set-up of an IP-based video system is easy -- once you’ve
set up an IP address, you’re up and running and it’s
extremely stable and reliable. Because this is the
technology of the future, it is also upgradeable. You won’t
be outgrowing an IP-based video surveillance system any time
soon because new developments are based on improving this
market. Therefore, you will be able to add on and improve
this system for years to come while older, CCTV+DVR hybrids
will dead-end and become obsolete.
Comparing analog and IP-based video surveillance
A better way to understand the differences between analog
and IP-based video surveillance may be to compare the two
and how they work:
Analog or CCTV+DVR video surveillance
- Easy to use -- operates like a VCR
- Changing cassettes and rewinding regularly means human
error frequently interferes with effectiveness
- Image quality is poor
- Storage tapes wear out over time
- Broadcasting images live isn’t practical
- Storage is bulky
- Uses analog recording, recording in low-grade picture
quality and inability to search and track easily
- Adding DVR systems must be done in ‘blocks’ of 16
channels
IP-based video surveillance
- IP-based recording means instant transmittal of images
anywhere in the world
- Can monitor multiple cameras from one remote location
- No decrease in recording quality over time or with
repeated replays
- Digital picture quality far superior to analog
- IP-base recording is highly compressed for easier
storage and can be transported over a variety of media
- Digital images can be encrypted for security purposes
- Updates and add-ons are relatively inexpensive through
software packages and Internet computer networking
- Adjustable frame rates
- Remote or shared viewing may be done over the Internet
or a wireless connection
- Standard IP video compression techniques are used
- IP surveillance cameras may be added individually or
in groups according to your needs
If you are contemplating increased or upgrading video
surveillance for your company or home, understanding how
IP-based video surveillance works will make your decision
easier. It is the future of video surveillance and, although
in the short term may be a bit more expensive, is obviously
an investment in superior quality and flexibility.
About the Author
Lori Wilkerson is a full-time freelance writer who loves her
job because it gives her the opportunity to learn more about
the world every day. Right now, she knows a little bit about
almost everything, and a lot about how to implement
video
security under low light conditions using a
night vision
security camera or
infrared camera. She has two dogs who are spoiled and
one teenager who is not.
Also See:
[ Effectiveness of
CCTV Security Systems in Crime Prevention ]
[ CCTV
Surveillance Systems Used for Crime Fighting & Prevention ]
[ History of
Public Video Surveillance ]
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