Ampere (amp)The unit of measure for the rate of electrical current flow characterized by the symbols l (in Ohm's law formulas) and A. One ampere is the current flowing through one ohm of resistance at one volt potential.
Aperture:The (Camera) lens opening that controls the amount of light that reaches the image sensor. Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture).
Auto Iris:A device in the camera lens that self-adjusts to light level changes. The Iris opens and closes to control the amount of light passing through the lens to reach the image sensor.
AGC (Automatic Gain Control):A feature of cameras that enhances videos of low lights to maintain the output video signal strength.
AWB (Automatic White Balance):A feature of cameras that automatically adjusts to varying light conditions to maintain the correct white balance on the image. Proper camera white balance has to take into account the "color temperature" of a light source, which refers to the relative warmth or coolness of white light. For more detail, click here
AWG (American Wire Gauge):AWG is the U.S. standard measuring gauge for certain conductors, including copper. The higher the AWG number the thinner the wire. This measure stems from the fact that the original measurement represented the number of times the wire was run through a wire machine which thus reduced the diameter of the wire.
Baud (Baud Rate):The rate at which data is transferred. Named after Maurice Emile Baud. The Baud rate is equivalent to bits per second in cases where each data event represents exactly 1 bit. To communicate, the baud rates of the equipment must be set the same. Note the baud rate and bit rate in a system can be different.
Bit Rate:The term bit rate is a synonym for data transfer rate. Bps = Bytes per second, bps = bits per second. The digital equivalent of bandwidth, bit rate is measured in bits per second. It is used to express the rate at which the compressed bit stream is transmitted. The higher the bit rate, the more information that can be carried.
BLC (Back Light Compensation):Cameras with BLC feature will adjust the brightness level of the image to compensate for the bright background so that more detail of the dark objects can be seen. For an example, when a camera is directed toward a door, the bright light from outside will normally make the overall image too bright to show detail on a subject backing to the door. BLC will compensate for the bright background so foreground objects are not silhouetted.
BNC Connector:BNC connector is a type of RF connector used for terminating coaxial cable. It is used for professional video connections. It is an alternative to the RCA connector. See also RCA Connector
C/CS Mount:Cine mount. The first standard for CCTV lens screw mounting. It is defined with the thread of 1''(25.4 mm) in diameter and 32 threads/inch, and the back flange-to-CCD distance of 17.526 mm (0.69''). The C-mount description applies to both lenses and cameras.
CS Mount (Cine Short Mount) is the newer standard for camera lens mounting. It uses the same physical thread as the C-mount, but the back flange-to-CCD distance is reduced to 12.5 mm.
C-mount lenses can be put on both, C-mount and CS-mount cameras, but must use a C-moun adaptor when used on a CS-mount camera.
CCD (Charge-Coupled Device):CCD and CMOS are two main types of technology in current security cameras. CCDs containing grids of pixels are used in Digital camera, Image scanner and video cameras as light-sensing devices.
CCDs boast higher sensitivity, and higher dynamic range than CMOS sensors while CMOS offers lower product cost and lower power consumption.
CCIR:Committée Consultatif International des Radiocommuniqué, which is the European standardization body that has set the standards for television in Europe. It was initially monochrome; therefore, today the term CCIR is usually used to refer to monochrome cameras that are used in PAL countries.
CCTV (Closed Circuit Television):A system in which the circuit is closed and all the elements are directly connected. The most widely applications of CCTV are in the security industry.
CIF (Common Intermediate Format):CIF is part of the ITU H.261videoconferencing standard. It specifies a data rate of 30 frames per second (fps), with each frame containing 288 lines and 352 pixels per line. A related standard, QCIF (Quarter CIF), transfers one fourth the amount of data.
CMOS:Complementary-symmetry/Metal-Oxide Semiconductor. CMOS image sensors which use the ASP (Active Pixel Sensor) technology, are one of the two major types of image sensors used in security cameras. The other is CCD image sensors
Comparing to CCDs, CMOS sensors are cheaper to make and consume less power, but they are more prone to noise.
Coaxial Cable:Coaxial cable is the most common type of cable used for transmitting a video signal through copper wire. This type of wiring has a coaxial cross-section where an outer shielding protects the actual interior signal conductor from electromagnetic interference. In the CCTV industry, the term "coax" usually refers to RG-59 cable with BNC-type plug ends.
CODEC (COder/DECoder):A CODEC is a device or software that compresses and/or decompresses digital signals. It is used for converting audio/video signals from analog to digital and vise vesa during the process of data transmission and storage. Each data format such MP4, AVI, etc. needs its own CODEC.
DVR (Digital Video Recorder):A device that records video/audio signals onto hard drive-based digital storage medium. In the CCTV security field, there are generally two types of DVRs, PC-based DVRs and Embedded DVRs. DVRs are replacing the traditionally widely used VCRs.
Gamma Correction:A correction of the linear response of a camera in order to compensate for the monitor phosphor screen non-linear response. It is measured with the exponential value of the curve describing the non-linearity. A typical monochrome monitor's gamma is 2.2, and a camera needs to be set to the inverse value of 2.2(which is 0.45) for the overall system to respond linearly (i.e., unity). All ICR's cameras have a gamma correction of 0.45.
HUE (color):One of the three characteristics of video picture, the other two are saturation and luminance. Hue defines color on the basis of its position in the spectrum.
Internet:The Internet is the worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked Web pages and other documents of the World Wide Web.
Contrary to some common usage, the Internet and the World Wide Web are not synonymous: the Internet is a collection of interconnected computer networks, linked by copper wires, fiber-optic cables, wireless connections, etc.; the Web is a collection of interconnected documents, linked by hyperlinks and URLs. The World Wide Web is accessible via the Internet, along with many other services including e-mail, file sharing and others See also Internet, LAN
LAN (Local Area Network):A Local Area Network (LAN) is a computer network covering a small local area, like a home, office, or small group of buildings such as a home, office, or college.
The mostly widely used term "Internet" refers to the global network that consists of all small computer networks, of which LAN is one type of them. LANs are connected together by WANs (Wide Area Networks).
The defining characteristics of LANs in contrast to WANs (wide area networks) are: their much higher data rates; smaller geographic range; and that they do not require leased telecommunication lines. See also Internet, WAN.
Luminance:Luminance defines the luminous intensity of a video signal: brightness and contrast. A color video picture contains two components, luminance - Y (brightness and contrast) and Chrominance - C (hue and saturation). It is normally measured by LUX.
LUX:Measurement unit of 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 m 2; It is also known as lumens per square metre. One lux is equal to approximately 0.09290 foot candle. Minimum illumination is an important specification of a CCTV camera. It reveals the minimum lighting needed for the camera to produce visible image.
Multiplexer (Mux):Multiplexer is a video switching device that accepts video input from multiple cameras and converts them to all display on one monitor and / or video recorder, similar to a quad video processor. However, a multiplexer is far more advanced than a simple quad processor. Video multiplexers use time division multiplexing, meaning that a full frame of video from each camera is recorded every few seconds. While multiplexed video does not achieve true realtime display or recording (there is a slight drag to the images on playback), multiplexers do offer the capability to change between a view of several cameras and a solid closeup view of only a single camera's view on playback of recorded video. When using multiple cameras, quads and multiplexers help to cut down on the amount of additional equipment needed for a dedicated surveillance system. However, DVR digital video recorders with multiple video inputs are quickly replacing quads and multiplexers. DVRs are now capable of doing what required a processor and VCR in the past (plus a whole lot more).
NTSC (National Television System Committee):NTSC is the analog television system in use in Canada, Japan, South Korea, the United States, and some other places, mostly in the America. It is named for the National Television System Committee, the industry-wide standardization body that created it.
PAL (Phase Alternation Aine):PAL is another major analog television system in use in large part of the world, mainly Europe, China, and other places. PAL system denotes 625 Lines and 50Hz comparing to NTSC system's 525 Lines and 60Hz.
PTZ (Pan/Tilt/Zoom):PTZ stands for equipment (mostly cameras) with the ability to pan, tilt, and zoom, usually by remote user control. Much of PTZ equipment is completely integrated, meaning there is only one controller necessary to operate all three features.
See ICRealtime's PTZ camera.
Quad Processor:Quad Processor is a video switching device that accepts video input from four cameras and converts them to all display on one monitor and / or video recorder.When using multiple cameras, quads and multiplexers help to cut down on the amount of additional equipment needed for a dedicated surveillance system. However, DVR digital video recorders with multiple video inputs are quickly replacing quads and multiplexers. DVRs are now capable of doing what required a processor and VCR in the past (plus a whole lot more).
Click here for info on ICR's quad processor.
RCA Connector:RCA connector is a common connector plug for standard consumer video and audio equipment. This type of connector plug may also be described as a "phono" plug. RCA jacks are found on all VCRs and televisions equipped to handle a composite video input. In most cases, RCA jacks are color coded yellow, white, and red. BNC plugs are easily adapted to standard consumer RCA connectors using a simple one-piece plug adapter.
Saturation (Color) :A color's saturation is the intensity of the color in the active picture. It is based on the color's purity; a highly saturated hue has a vivid, intense color, while a less saturated hue appears more muted and grey.
Simplex, Duplex, Triplex, Pentaplex:These terms concern the operation of video recorders (VCR, DVR) and multiple camera video processors like quads and multiplexers. They indicate the number of device's capacities that can be used simultaneously. For instance, a simplex device is only capable of performing one type of task at a time, whether that be recording or playback. A duplex device can perform two simultaneous functions like record and configure the monitor display. Triplex devices are capable of three tasks at the same time (usually record, playback, and zoom or other display functions). Pentaplex devices can perform six different tasks at the same time. ICRealtime's DVRs are all Pentaplex devices which can record, playback, liveview, remote liveview, remote search, and remote configuration change simultaneously More Detail on DVRs.
S/N Ratio (Signal to Noise Ratio):Signal to Noise Ratio indicates the ratio of noise to actual total signal (in a video or audio signal). The S/N number measures how much higher the signal level is to the level of background electronic noise, so a higher number means a clearer and crisper picture. Signal-to-noise ratio is expressed in decibels (dB). More Detail
Uninterruptible Power Supply (UPS):UPS sometimes called an uninterruptible power source, is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source when utility power is not available.
WAN (Wide Area Network):A wide area network or WAN is a computer network covering a wide geographical area, involving a vast array of computers. This is different from local area networks (LANs) that are usually limited to a room, building or campus. The most well-known example of a WAN is the Internet.
WANs are used to connect local area networks (LANs) together, so that users and computers in one location can communicate with users and computers in other locations.