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Terminology > [Q - R]
Video Surveillance Glossary of Terms [Q - R]
- » QCIF
[top]
This resolution is one quarter of CIF,
with 144 lines and 176 pixels per line.
- » Quad
[top]
Utilizing digital video, this piece of
equipment displays signals from four surveillance cameras on
one monitor.
- » Range finder
[top]
This is a device that determines the
required focal length and the resulting monitor image.
While looking through it, the user can adjust the range
finder to get the optimal image, with numbers on the range
finder displaying the needed focal length.
- » Raster
[top]
A raster is a rectangular scan pattern
of lines that the picture is created upon. It also refers
to an active TV monitor that has no video information
displayed.
- » Real Media
[top]
Real Networks developed an early
multimedia protocol for video and audio (often streaming)
called Real Media.
- » Real time video
[top]
Any picture having 24 or more frames
per second appears continuous, or in real time.
- » Reed switch
[top]
This type of alarm activating device
becomes active when contact is either opened or closed, as
in a door or window being opened or closed. They are also
capable of switcher activation to activate the relevant
security camera.
- » Regulated power supply
[top]
A DC power supply with a minimal ripple
factor is considered to be regulated.
- » Remote head surveillance camera
[top]
For surveillance situations where space
is limited, this type of camera separates the CCD chip from
the camera body by cable, considerably shrinking the overall
camera size.
- » Remote monitoring
[top]
This allows an off site user to monitor
surveillance camera feeds, so a user can survey a site
regardless of their location from it. The transfer of data
from camera to user can be either over the Internet or the
Ethernet, with IP cameras being suited to the task.
- » RF (Radio Frequency)
[top]
In order to be broadcast across a
wireless network, video signals must be modulated into a RF
signal.
- » RG-11
[top]
Having a thick center core, this type
of coaxial cable is used to transmit video signals of up to
550m.
- » RG-59
[top]
More commonly used than RG-11 for CCTV,
this coaxial cable transmits video signals of up to 230m.
- » RGB (Red Green Blue)
[top]
These are the three primary colors of
light. All other colors are derived from their mixture.
- » Ripple factor
[top]
Too little filtering in a DC power
supply creates an amplitude variation called the ripple
factor; with large amounts of it able to damage DC powered
surveillance cameras.
- » ROI (Region of Interest)
[top]
Applied to the field of video
surveillance, ROI stands for Region of Interest, meaning an
area of the frame where motion is detected, in turn
activating the surveillance camera.
- » Router
[top]
A router is a piece of equipment
facilitating the exchange of packets throughout LAN or WAN
networks. It moves packets across a predetermined path to
their destination by storing and forwarding the packets, and
then determining their optimal path along the network. A
router is hardware based, but can also include software.
- » RS232 (or RS-232)
[top]
This is the communication standard that
applies to PC serial communications. RS232 is commonly used
as the mechanism for sending instructions that control PTZ
security camera movement.
- » RTP (Real-time Transport Protocol)
[top]
The Internet Engineering Task Force
(IETF) developed RTPs to specify audio and video signal
management. It standardizes the packet formatting for both
for easy synchronization and Internet delivery. Streaming
media systems and video conferencing systems use RTP, while
DVR systems rely on this protocol in the implementation of
the remote view feature. Since it doesn’t specify how video
surveillance playback is implemented, the data from
different RTP based surveillance systems usually cannot
interoperate.
- » RTSP (Real Time Streaming Protocol)
[top]
This open standard for Internet
streaming of audio and video is popular among DVR makers for
remote viewing of live or stored security camera video over
the Internet. RTSP controls the transmission of the data
stream much the way a television remote controls the
television. Like RTP, interoperability problems exist
between different DVR systems.
About the Author
Ben Davidson is an experienced freelance writer of
technological subjects. His work provides clear and valuable
information about
surveillance cameras,
CCTV systems, and
digital video
recorders for consumers looking to make video security
purchases for their home or business.
Also See:
[
How
IP Based Video Surveillance Works ]
[
History of
Video Surveillance ]
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