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Terminology > [P]
Video Surveillance Glossary of Terms [P]
- » PAL (Phase Alternating Line)
[top]
Europe’s television video signal
standard is known as PAL. PAL uses 625 picture lines and a
50Hz field frequency, and is incompatible with NTSC.
- » Passive
[top]
If a system component is non-powered,
it is considered passive.
- » PCMCIA Card (Personal Computer Memory Card International Association)
[top]
These storage devices resemble a credit
card and are typically used to expand the hardware
functionality of portable devices such as laptops. In video
surveillance application, PCMCIA cards can be used with
portable PCs to add real-time full motion video capture of
live security video. When used with digital cameras, they
provide portable storage and a method for saving and
transferring photos between digital cameras and PCs.
- » Pelco-D
[top]
This Pelco created protocol is used to
control PTZ security camera movement.
- » Photon
[top]
A photon is the basic unit of light.
- » Pinhole Camera
[top]
Perfect for covert surveillance, this
quarter sized camera is nearly impossible to detect. With
it’s small size comes limited abilities though, primarily a
small lens and limited zoom capabilities.
- » Pixel (Picture Element)
[top]
Pixels are the smallest possible
display unit of visual information available for building a
graphical image. It is also the basic unit of a CCD chip,
with most CCD chips being comprised of over 300,000 pixels.
- » PoE (Power over Ethernet)
[top]
This abbreviation refers to a method of
supplying power to an IP camera using Category 5 Ethernet
cables over a physically wired LAN network.
- » Polarizer
[top]
This filter eliminates light reflected
from glass, water, and other surfaces, thereby minimizing
unwanted visual glare affects from glass and other
non-metallic surfaces.
- » Post-Record
[top]
Sometimes referred to as post-record
time, this is a DVR's ability to record after a motion
detection event has occurred. It records for a specified
amount of time after the event has been triggered, even
though the motion may have ceased.
- » Potentiometer
[top]
This device measures voltage or a
potential voltage difference by comparing it with a standard
voltage. It can also change resistance by moving the
contact point, and is used to record pre-set positions in
both zoom lenses and pan tilt heads.
- » Power supply
[top]
Most security cameras utilize 24V AC or
12V DC power supplies. A power supply is usually plugged
into a regular electrical outlet or part of a centralized
power supply.
- » PPP (Point-to-Point Protocol)
[top]
Point-to-point Protocol is the primary
method used in establishing a direct connection between two
devices on a network (usually a computer and the Internet).
It is a communication protocol between computers using one
of several methods: usually TCP/IP, telephone lines, or
ISDN.
- » Pre-Record
[top]
This DVR capability will record video
prior to motion being detected, then send to the disk as
much prior video as memory allows and video of the motion
itself.
- » Pressure mat
[top]
Placed before doorways, gates, and
other entrances, this device responds to pressure (usually
being walked or stood upon) to either open doors or activate
the surveillance camera trained on that area.
- » Progressive
[top]
Since it scans all lines onscreen at
once, 60 times per second, this type of scanning is used by
computer monitors to minimize flickering. It is also better
able to show movement, offering more detail and less
ghosting than interlaced scanning.
- » Protocol
[top]
Protocols are standard procedures used
for regulating data transmission between computers.
Protocols exist to minimize errors during the exchange of
data.
- » PTZ Camera
[top]
PTZ stands for Pan, Tilt, and Zoom.
These cameras are usually remotely controlled by software or
a joystick. PTZ cameras are used when active real time
monitoring with the ability to point the camera’s viewing
area to a specific action or event is desired.
- » PTZ controller
[top]
The controller used to control PTZ
camera movement, usually software or a joystick.
About the Author
Ben Davidson is an experienced freelance writer of
technological subjects. His work provides clear and valuable
information about
CCTV
systems,
surveillance
equipment, and
wireless home
security products for consumers looking to make purchases
to secure
their home or business.
Also See:
[
How
IP Based Video Surveillance Works ]
[
History of
Video Surveillance ]
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