Glossary I-L

Index | A-D | E-H | I-L | M-P | Q-T | U-Z


IEEE 1394 aka FireWire

Networking standard for PCs. Combined with 5C copy protection, is used as a two-way connection to transfer the MPEG-compressed digital bitstreams between consumer electronics items, including HDTV tuners and displays, D-VHS recorders, DVD players, and DBS receivers. Also called FireWire, iLink, …


See IEEE 1394

I.R. (Infra Red)

A range of frequencies lower than visible red light used for covert surveillance or as a low cost wireless video link.

Image Burn (Retained Image)

A change produced in or on the target of the pickup device which remains after the removal of a previously stationary light image.

Image Capture System

A hardware and software system used to obtain and save personal data and cardholder photographic images.


The effective resistance of an electronic circuit to an A.C. signal.

Infrared Illumination

When a scene is subject to dark conditions, active infrared illumination must be applied for best results. Active infrared illumination is a new surveillance technology that is so effective that the images produced are often mistaken for regular daytime monochrome images. Active infrared illumination is a cost-effective technology for enabling truly effective 24/7 surveillance in any lighting conditions including total darkness.

Insertion Loss

The signal strength loss that occurs when a piece of equipment is inserted into a line.


An electronic device that creates an output image brighter than the input (original) image. Optical amplifier.


A scanning process where every other horizontal line is scanned in one field while the alternate lines are scanned in the next field to produce a complete picture frame.

IP Address

The Internet Protocol address; a unique numeric address such as Also see Static IP and Dynamic IP.


The adjustable opening (mechanical diaphragm) through which light can pass and be regulated.

ISO Magnetic Stripe Encoder

International Standards Organization specification for magnetic stripe encoding. The encoder supports dual high/low coercivity and tracks 1, 2 and 3.



A digital image format commonly used in digital recording, for storing high-quality color and grayscale photographs in compressed bitmap form.



One of the basic physical units of measurement for temperature. The scale is the same as the Celsius, but the 0ºK starts from -273ºC. Also the unit of measurement of the temperature of light is expressed in Kelvin’s or K. In color recording, light temperature affects the color values of the lights and the scene that they illuminate.


Kilohertz. Thousand Hertz.


1024 bytes



Local Area Network. A short distance data communications network (typically within a building or campus) used to link computers and peripheral devices.


A transparent optical component that converges light rays to form a two dimensional image of that object.

Level Control

Main iris control. Used to set the auto-iris circuit to a video level desired by the user. After set-up, the circuit will adjust the iris to maintain this video level in changing lighting conditions. Turning the control towards High will open the iris, to

License Plate Reading

License plate reading requires specialized equipment in order to successfully overcome the challenges related to speed, lighting, reflectivity and headlight glare. Cameras chosen should be designed specifically for license plate reading as most conventional cameras will not work on a consistent basis. Infrared lighting is typically required for performance during both day and night.

Line Amplifier (Video Line Corrector)

A device to make good the loss of signal strength and quality due to long cable runs.

Line Lock

To synchronize the field sync pulses, of an AC powered camera, to the frequency of the voltage input (line voltage).


Range refers to the ideal broadcast range of wireless audio/video link (transmitter and receiver) systems. Line-of-sight means the range when there is a visible pathway between the transmitter antenna and the receiver antenna.

Liquid crystal display (LCD)

A screen for displaying video/text/graphics based on a technology called liquid
crystal, where minute currents change the reflectiveness or transparency of the screen. The advantages of LCD screens are very small power consumption (can be easily battery driven) and low price of mass-produced units.


Abbreviation for Low Coercivity. Easier to encode and slightly less expensive than HiCo magnetic stripe cards.


A term indicating that a high impedance device has been permanently connected in a parallel to a video source. Individual balanced video outputs for each video input.

Low Light (or low lux)

Sensitivity refers to a camera's performance under low lighting conditions. Specifications list the absolute lowest light level at which some pixels will be altered.

Lumen [lm]

A light intensity produced by the luminosity of 1 candela in one radian of a solid angle.


Refers to the video signal information about the scene brightness. The measurable, luminous intensity of a video signal. Differentiated from brightness in that the latter is non-measurable and sensory. The color video picture information contains two components, luminance (brightness and contrast) and chrominance (hue and saturation).

Luminance (Y)

The part of a video signal that consists of the monochrome data.


A unit measuring the intensity of light. It is defined as the illumination of a surface when luminous flux of 1 lumen falls on an area of 1 m2. It is also known as lumen per square meter, or meter-candelas.One foot-candle = 10 lux.

Index | A-D | E-H | I-L | M-P | Q-T | U-Z