Axis 206 User Manual page 35

pictures (known as fields) per second, of which every 2
consecutive fields (at half height) are then combined into 1
frame. Interlacing was developed many years ago for the
analog TV world and is still used widely today. It provides
good results when viewing motion in standard TV pictures,
although there is always some degree of distortion in the
image.
To view interlaced video on e.g. a computer monitor, the
video must first be de-interlaced, to produce progressive
video, which consists of complete images, one after the
other, at 25 frames per second. See also Progressive scan.
IP (Internet Protocol) - The Internet Protocol is a method
transmitting data over a network. Data to be sent is divided
into individual and completely independent "packets." Each
computer (or host) on the Internet has at least one address
that uniquely identifies it from all others, and each data
packet contains both the sender's address and the receiver's
address.
The Internet Protocol ensures that the data packets all arrive
at the intended address. As IP is a connectionless protocol,
which means that there is no established connection
between the communication end-points, packets can be sent
via different routes and do not need to arrive at the
destination in the correct order.
Once the data packets have arrived at the correct
destination, another protocol - Transmission Control
Protocol (TCP) - puts them in the right order.
See also TCP.
IP address - An IP address is simply an address on an IP
network used by a computer/device connected to that
network. IP addresses allow all the connected
computers/devices to find each other and to pass data back
and forth.
To avoid conflicts, each IP address on any given network
must be unique. An IP address can be assigned as fixed, so
that it does not change, or it can be assigned dynamically
(and automatically) by DHCP.
An IP address consists of four groups (or quads) of decimal
digits separated by periods, e.g. 130.5.5.25. Different parts
of the address represent different things. Some part will
represent the network number or address, and some other
part will represent the local machine address. See also IP
(Internet Protocol).
Infrared (IR) - Infrared radiation is radiation at a longer
wavelength than visible light, which means it cannot be
seen by the naked human eye. As infrared radiation can be
detected as heat, this can be shown on a screen or captured
by a digital camera, with hotter objects showing up brighter
against colder surroundings (e.g. a human body against a
colder background).
As color cameras can "see" infrared radiation as well as
visible light, these cameras are equipped with an IR-cut
filter, to prevent distortion of the colors the human eye can
see. To use the camera in very dark locations or at night,
this filter can be removed, to allow infrared radiation to hit
the image sensor and thus produce images. An infrared
lamp can be used for improved illumination for night
surveillance, whilst not producing any extra visible light.
Inputs/Outputs (I/O's) - The digital I/Os on, for example, a
network camera can be used to connect any device that can
toggle between an open and a closed circuit.
For example, if a door switch is used as an input device,
opening the door could trigger the upload of video images
and the sending of notification messages.
An output might, for example, be used to automatically
start a siren when there is a motion detection trigger.
ISMA (Internet Streaming Media Alliance) - ISMA's goal
is: "To accelerate the adoption and deployment of open
standards for streaming rich media content such as video,
audio, and associated data, over Internet protocols."
AXIS 206 - Glossary
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