| 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. |
| Ident |
Number or title super-imposed on a video signal. |
| Image Sensor Format |
Size of the CCD element in the camera. |
| Impedance |
The effective resistance of an electronic circuit to an A.C. signal. |
Interlace (2:1
interlace) |
The accurate combining of two fields, one odd one even, into a single frame. |
| Interleaving |
Method used with alarms or activity detection which allows extra frames of video from alarmed cameras to be added to a time multiplexed sequence whilst a state of alarm exists. |
Interline Transfer
CCD |
Type of CCD chip in which the photosensors acquire and store an electric charge according to the intensity of light falling on them. The charges are first transferred to a vertical shift register and then a horizontal shift register. This is controlled by an external pulse timing system. |
Internal Sync
(crystal
controlled) |
A camera that generates its sync pulses without reference to any other source. Normally using a crystal controlled oscillator. |
| Internet |
1) Any large network made up of several smaller networks.
2) A group of networks that are interconnected so that they appear to be one continuous large network and can be addressed seamlessly at the OSI Network layer through routers.
3) The industry name for the Worldwide interconnected network. Based upon the original ARPANET network, it’s used as a reference resource, a way of sending e-mail and an online chat room for users around the world. |
| Intranet |
A network connecting a related set of standard Internet protocols and files in HTML format with employees using Internet browsers in an organisation’s network and within the corporate firewalls. |
IP (Internet
Protocol) |
The protocol used in gateways to connect networks at the OSI Network Layer (Layer 3) and above. IP routes a message across networks. |
Iris (Iris
diaphragm) |
Adjustable diaphragm that regulates the amount of light passing through a lens. |
ISDN (Integrated
Services Digital
Network) |
A digital switched network used to transmit voice, data, images or video. Also see BRI |
