| Word |
Description |
| A.L.C. (Automatic Level Control) |
On AI lenses, also known as the peak/average control. Adjusting this control allows the auto iris circuitry to either take bright spots more into consideration (peak), bringing out detail in bright areas, or less into consideration (average) bringing out |
| Active pixel sensor |
An active-pixel sensor (APS), also commonly written active pixel sensor, is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web cameras and in some DSLRs. Such an image sensor is produced by a CMOS process (and is hence also known as a CMOS sensor), and has emerged as an alternative to charge-coupled device (CCD) imager sensors. CMOS image sensor The term active pixel sensor is also used to refer to the individual pixel sensor itself, as opposed to the image sensor; in that case the image sensor is sometimes called an active pixel sensor imager, active-pixel image sensor, or active-pixel-sensor (APS) imager. |
| Activity Detection |
A feature of the Generation 3 video multiplexer range that uses video motion detection techniques to improve the camera update times. It also gives a relay closure. |
| Alarming |
The ability of CCTV equipment to respond to an input signal, normally a simple switch closure. The response varies depending on equipment type, most common is for switcher to hold on the camera corresponding to the alarm input. |
| Algorithms |
Complex mathematical formula or rules used to solve problems. In CCTV (closed circuit television), they are used to achieve digital compression of a video picture. |
| Alkaline Battery |
Type of DC power source with a longer life compared to a standard battery. It cannot be recharged. |
| Amplitude |
Refers to the strength of the video signal at a point and is measured in volts. |
| Analog |
A signal in which any level is represented by a directly proportional voltage; not digital. |
| Angle of refraction |
The angle of bending of light when it travels from one medium into another. |
| Angle of view |
Represents the area of the scene (maximum horizontal and vertical angle) that can be seen through a lens. It is measured in degrees. |
| Aperture |
The lens opening that controls the amount of light reaching the pickup device (imager). |
| Aspect ratio |
The ratio between the horizontal and the vertical lengths of the video picture. The aspect ratio for NTSC and PAL systems is 4:3. |
| Aspherical Lens |
A lens designed with a non spherical shape so that it refracts the light passing through it to either lower the lens aperture so that it passes more light or decreases barrel distortion on wide angle lenses. |
| Attenuation |
A reduction or loss in the strength of light or an electrical signal and is usually measured in decibels. |
| Audible detector |
A device which detects sound. In cctv (closed circuit television), it can be interfaced with a switcher so that a nominated surveillance camera is switched on when the detector is activated. |
| Audio file format |
Container format for storing audio data on a computer system. The general approach towards storing digital audio is to sample the audio voltage which, on playback, would correspond to a certain position of the membrane in a speaker of the individual channels with a certain resolution the number of bits per sample in regular intervals (forming the sample rate). This data can then be stored uncompressed, or compressed to reduce the file size. |
| Auto balance |
system of detecting and automatically correcting errors in the amplitude of color signals. |
| Auto iris |
A diaphragm which is inbuilt in a lens to automatically control the amount of light falling on the chip. The tiny motors in the lens open or close the diaphragm, depending upon the amplitude of the video signal. |
| Auto White Balance |
Feature on color cameras whereby the camera constantly monitors the light and adjusts its color to maintain white areas. |
| Auto-Terminating |
Feature whereby the equipment automatically selects the correct termination depending on whether the video output BNC is connected. |
| Automatic Frequency Control (AFC) |
An electronic circuit used whereby the frequency of an oscillator is automatically maintained within specified limits. |
| Automatic Gain Control (AGC) |
An electronic circuit used by which the gain of a signal is automatically adjusted as a function of its input or other specified parameter. |
| Automatic Iris Lens |
A lens in which the aperture automatically opens or closes to maintain proper light levels on the camera's pickup device. |
| Automatic pan |
A feature of a pan/tilt or pan only head which allows the head to continuously move (pan) left and right between two fixed points. These fixed points can be set by adjusting the limit switches in the head. |
| Average video signal |
Represents the average light level of the whole picture used to open or close the automatic iris in the lens. |
| B.L.C. (Back Light Compensation) |
A feature of modern CCD cameras which electronically compensates for high background lighting to give detail which would normally be silhouetted. |
| Back Focus |
The mechanical aligning of the imaging device with the focal point of the lens. Most important on zoom lenses to ensure the image stays in focus throughout the zoom range. |
| Balanced cable |
A type of cable in which the signal is divided over a pair of cables and travels in opposing polarity. This reduces interference allowing transmission over longer distances. |
| Balanced Signal |
Method of transmitting video, usually over twisted pair cable, that consists of two equal but opposite signals being sent down two conductors. |
| Band Width |
The frequency range of a signal. The span that the information-bearing signal occupies or requires or the difference between the lowest and highest frequency of a band. |
| Bandwidth |
The range of frequencies that pass through an electrical/electronic amplifying, processing or transmission unit without attenuation or loss. |
| Barrel distortion |
A distortion in the monitor due to non uniform scanning which causes the image to bulge outwards like a barrel. |
| Base-Band Video |
Unmodulated video signal suitable for display on a monitor but not a domestic TV. |
| Beam angle |
The angular beam width of a conical beam of light and is measured in degrees. |
| Black Level |
The level of the video signal that corresponds to the maximum limits of the black areas of the picture. |
| Blanking (Field And Line Flyback Blanking) |
The operation of turning off the monitor display, or pick-up device, during sync pulses to avoid thin white lines appearing on the picture. |
| Blanking pulse |
A black pulse added during the fly back period to make the video signal invisible on the screen. |
| Blooming |
The halation and defocusing effect that occurs around the bright areas of the picture (highlight) whenever there is an increase in the brightness intensity. |
| BNC |
Video connector, the most commonly used in CCTV. |
| BNC connector |
A type of connector used to interconnect two coaxial cables or connect a cable with other cctv (closed circuit television) components |
| Bridging |
A term indicating that a high impedance video line is paralleled, usually through a switch, to a source of video. A separate overall video output. |
| Bridging switcher |
A type of sequential switcher which has two outputs. The sequencing output sequences all the surveillance camera inputs whereas the other output is a spot output where any surveillance camera can be called up for extended viewing. |
| Brightness |
Represents the intensity of illumination of the reproduced picture. |
| Brightness Control |
A control in the monitor which does not change the amplitude of the video signal but increases or decreases the illumination of the phosphors on the screen. |
| Broadcast camera |
A high quality camera using three CCD chips. It is used extensively in the professional broadcasting industry. |
| C Mount / CS Mount |
The two industry standards for mounting a lens on a camera. The C-Mount lens has a 17.5mm flange back distance. The CS-Mount lens has a 12.5mm flange back distance. |
| C-mount |
A lens mount with 17.526 mm back flange. Back flange is the distance between the lens mounting surface and the CCD chip. |
| C.C.I.R. |
The European TV standard 625 lines 50 fields. |
| Cable compensated amplifier |
High frequency video signals are attenuated when transmitted through cables. A cable compensated amplifier boosts the high frequency signals depending upon the cable distance. This ensures minimum video loss. |
| Cable core |
The central part of the cable which actually carries the video , control or power signals. It can be made up of a single conductor (solid core) or a number of electrical wires. |
| Cable jacket |
The outer protective coating which covers the core of the cable. |
| Cable tray |
A long tray installed in many sites which allows cables to be economically laid out. |
| Camera |
A device that translates light into a video image and transmits that image to a monitor for viewing. It contains the image sensor and other electronic circuitry to create a video signal. |
| Candela |
A new unit which replaces the candle and is a measurement of luminous intensity. |
| Card Reader (SD) |
A device for reading a card containing a code or signal; an intelligent reader that compares data on a card against preprogrammed parameters. Entry or exit is granted or denied by the card reader at the reader location. |
| Cathode ray tube (CRT) |
A tube in the monitor containing a heated cathode which emits a beam of electrons focused on a phosphor coated surface. The surface glows depending upon the intensity of the beam. The deflection circuitry in the tube controls the movement of the beam. |
| CATV |
Short for Cable Access Television. The method for distributing RF signals via coaxial cable rather than radiated through the air. |
| CCD |
Charged Coupled Device. This is a solid state semiconductor imaging device often referred to as an integrated circuit, chip or "imager." Solid state cameras are sometimes referred to as CCD cameras. |
| CCD Charge Coupled Device |
solid state device in a surveillance camera that converts light falling on it into an electrical signal. |
| CCD iris |
A feature in modern CCD surveillance cameras by which the iris function is performed by the CCD chip itself. This eliminates the need for an auto iris lens. The CCD iris can handle minor light fluctuations only and therefore is not recommended for most outdoor applications. |
| CCIR International Radio Consultative Committee |
Recommends a format of 625 lines per frame and a transmission speed of 25 frames per second. |
| CCTV |
The common abbreviation for Closed Circuit Television. A private or closed television system. |
| CD-RW |
A CD-ROM that can be written, erased, and rewritten by a CD-RW drive. |
| Celsius |
The metric unit for measuring temperature. In this scale, the boiling point of water is 100 degrees. In the USA, the unit used to measure temperature is Fahrenheit. |
| Channel separation |
When signals are multiplexed at different frequencies for transmission, then the separation between these frequencies is called channel separation. Poor separation can lead to cross talk. |
| Chromatic aberration |
An error in lenses which causes the focal point to be scattered. This occurs because different wavelengths of light bend differently through a lens. A combination of lenses are required to minimize this error. |
| Chrominance (C) |
The part of the video signal corresponding to the color information. |
| Chrominance signal |
That part of the video signal which contains the color information. In S-VHS, this signal is transmitted along a separate cable. In a composite video signal, the chrominance signal is multiplexed at a higher frequency and sent along the same cable. |
| Closed Circuit Television (CCTV) |
A television installation in which the signal is transmitted to a defined number of receivers. |
| Coaxial Cable |
A type of shielded cable capable of carrying a wide range of frequencies with very low signal loss. |
| Codec |
A codec is computer program capable of encoding and/or decoding a digitaldata stream or signal. The word codec is a portmanteau of 'compressor-decompressor' or, most commonly, 'coder-decoder'. Short for compression/decompression, a codec is an algorithm or special computer program that reduces the number of bytes consumed by large files. ...Codec stands for Coder/Decoder. Basically it is a piece of software or a driver that adds a support for certain video/audio formats for your audio or video products |
| Color stripe filter |
A type of filter placed in front of a color CCD chip. It breaks up light into the basic colors - red, green and blue which are then directed to separate pixels in the CCD chip. |
| Common sync generator |
A device used to synchronize surveillance cameras. It generates synchronizing pulses that are sent to all surveillance cameras connected to it by coaxial cable. |
| Composite video |
A standard signal format in cctv (closed circuit television) which contains the video signal, the horizontal and vertical sync pulses and the blanking pulses. The sync pulses are 0.3 volts and the video signal is 0.7 volts. |
| Computer Security |
A general term relating to measures designed to protect computer assets in all configurations. |
| Conduit |
A plastic or metallic tube which is used to conceal, protect or secure cables. |
| Connector |
A device used to interconnect cables or connect cables to various equipment. |
| Contrast |
The difference in the intensity between the black parts and white parts of the picture on the monitor. |
| Contrast Control |
A control in the monitor which changes the contrast by increasing or decreasing the amplitude of the video signal. |
| Covert |
A mode of cctv (closed circuit television) surveillance in which the surveillance camera and lens are hidden and cannot be seen.
Secrecy: Secrecy or furtiveness is the practice of sharing information among a group of people, which can be as small as one person, while hiding it from all others. That which is kept hidden is known as the secret. Secrecy is often controversial, depending on the content of the secret, the group or people keeping the secret, and the motivation for secrecy. Secrecy by government entities is often decried as excessive or in promotion of poor operation; excessive revelation of information on individuals can conflict with virtues of privacy and confidentiality. |
| Crimping |
A process of connecting a cable to a connector without screwing or soldering using a special tool. In crimping a BNC connector, the center pin of the connector is uniformly pressed against the cable core. To ensure a proper connection, a good crimping tool is needed. |
| Crosstalk |
An undesired signal that interferes with the desired signal. |
| Db (Decibel) |
A measure of the power ratio of two signals. It is equal to ten times the logarithm of the ratio of the two the iris. |
| DC Type Lens |
An auto-iris lens with internal circuit which receives voltage and a video signal from the camera to adjust signals. |
| Depth of field |
The distance between the nearest and furthermost points of the scene which appear in sharp focus. It depends upon the F-stop and focal length of the lens. |
| Digital |
A signal that levels are represented by binary numbers. These can be kept in a store. |
| Digital Recording |
This is the latest form of recording and is relatively new to the CCTV industry as a result is not the most economical method however it does have several advantages over the VCR analogue tape recorders. First of all it enables quick access to the desired |
| Digital Video Recorder (DVR) |
A digital video recorder (DVR) or personal video recorder (PVR) is a device that records video in a digital format to a disk drive or other memory medium within a device. The term includes stand-alone set-top boxes, portable media players (PMP) and software for personal computers which enables video capture and playback to and from disk. Some consumer electronic manufacturers have started to offer televisions with DVR hardware and software built in to the television itself; LG was first to launch one in 2007.A digital camcorder combines a camera and a digital video recorder. Also, mobile phones often have a camera as well as some digital video recording capability.
DIGITAL RECORDING Technology that enables images from a camera to be stored on a hard drive. A digital recorder provides clearer images than videotape and faster access to them Digital video recorder (DVR). A special computer that converts analog computer images to digital images, compresses the images, and then stores them for later viewing. A DVR replaces the time-lapse VCR, multiplexor and switch found in analog CCTV surveillance systems.
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| Display Resolution "Common Display Resolutions" |
The display resolution of a digital television or display typically refers to the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube (CRT) and flat panel or projection displays using fixed picture-element (pixel) arrays. One use of the term "display resolution" applies to fixed-pixel-array displays such as plasma display panels (PDPs), liquid crystal displays (LCDs), digital light processing (DLP) projectors, or similar technologies, and is simply the physical number of columns and rows of pixels creating the display (e.g., 1280 X1024). A consequence of having a fixed grid display is that for multiformat video inputs all displays need a "scaling-engine" (a digital video processor that includes a memory array) to match the incoming picture format to the display. Note that the use of the word resolution here is misleading. The term "display resolution" is usually used to mean pixel dimensions (e.g., 1280x1024), which does not tell anything about the resolution of the display on which the image is actually formed (which would typically be given in pixels per inch (digital) or number of lines measured horizontally, per picture (analog) |
| Distribution Amplifier |
A device that accepts a video signal and sends it out over a number of independent outputs. |
| Dome |
A type of surveillance camera housing made of smoked or tinted plastic. It is excellent for discreet surveillance and is also available with in built pan/tilt heads. |
| DSP chip |
Digital Signal Processing chip is a solid state device which converts an analogue video signal into a digital video signal. It is used in digital surveillance cameras and also in computers to digitizes video images. |
| Duplex |
A system which can handle simultaneously two channels of video, audio or data signals. |
| Duplex (Multiplexer) |
A multiplexer with two frame stores allowing it to show multi-screen pictures while performing time multiplex recording. |
| Dwell Time |
The length of time a switcher displays one camera before sequencing to the next. Usually a variable setting. |
| Dynamic IP Address |
A Dynamic IP address is a type of account from an ISP (internet service provider) where your computer or network is assigned an IP address that constantly changing and never remains the same. Also see IP Address and Static IP. |
| E.I. (Electronic Iris) Shutter |
Electronic Iris shuttering is the ability of the camera to compensate for moderate light changes in indoor applications without the use of auto iris lenses. |
| E.I.A. (Electronic Industry Association) |
US TV standard 525 lines 60 fields. |
| Electronic shutter speed |
See Shutter speed |
| Equalization |
The process of correcting losses of certain components in a signal. |
| Ext. Sync (External Sync) |
The ability of CCTV equipment, normally cameras, to accept one or more of the standard sync formats so as to align itself to the rest of the system. |
| F-Stop |
A term used to indicate the speed of a lens. The smaller the f-number, the greater is the amount of light passing through the lens. |
| Facial Capture |
Corner mounted cameras are very effective at capturing overview scene surveillance. In order to obtain facial capture surveillance for positive identification purposes, cameras should be mounted at vertical height conducive for facial capture (for example, in light switches). Lenses selected should produce identification level imaging, ie no less than 120% vertical image of the person. |
| Fast lens |
A lens which can gather and transmit more light to the surveillance camera. A fast lens has a larger iris opening and therefore a smaller F-stop. |
| Fast scan video |
A method of sending video images over the telephone network to any part of the world. The update rate presently is not real-time but is improving continuously. |
| Fiber Optic |
The process of transmitting light through a long, flexible fiber such as glass or plastic, for the purpose of transmitting video, audio, or data over long distances. |
| Fiber optics |
A method of modulating video, audio or data with a light beam and transmitting it along a glass core. |
| Field |
One half of a frame and consists of 312.5 (PAL) and 262.5 (NTSC) lines. Odd and even fields are combined to form a single frame. |
| Field of view |
The and width of the view that can be seen through a lens. The maximum angle of view that can be seen through a lens or optical instrument. The image area produced by any camera and lens combination (See focal length) . |
| Fish Eye |
(See Wide angle lens) |
| Fixed lens |
A lens with a fixed focal length. A wide range of fixed lens are available to suit different applications e.g. 2.6mm, 4.8mm, 8mm, 16mm, 25mm, 75mm etc. |
| Flange Back |
The distance from the flange of the lens (beginning of the lens mount) to the focal plane. C-mount lenses have a flange back distance of 17.526mm vs. 12.5mm for CS-mount. |
| Flash memory |
Also associated with Internal Memory Flash memory is a non-volatilecomputer memory that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives for general storage and transfer of data between computers and other digital products. It is a specific type of EEPROM (Electrically Erasable Programmable Read-Only Memory) that is erased and programmed in large blocks; in early flash the entire chip had to be erased at once.
Example applications include PDAs (personal digital assistants), laptop computers, digital audio players, digital cameras and mobile phones. Flash memory is non-volatile, which means that no power is needed to maintain the information stored in the chip. These characteristics explain the popularity of flash memory in portable devices. Another feature of flash memory is that when packaged in a "memory card," it is enormously durable, being able to withstand intense pressure, extremes of temperature, and even immersion in water. |
| Fluorescent lamp |
type of artificial light source in which the mercury vapor generated by a low wattage arc strikes the phosphor material to emit light. It is popularly used in indoor applications. |
| Focal length |
The distance between the optical center of a lens and the point of focus. It is usually measured in mm or inches. |
| Focus |
The focal point. An adjustment to the lens optics to improve the clarity of the picture. |
| Focus ring |
A ring on a lens which is rotated to obtain correct focus. It is available only in manual iris lenses. |
| Foot Candle (FC) |
A measurement of light. 1 lumen per square foot. |
| Format |
The size of the camera's pickup device (imager). Current standard formats are 1/4", 1/3" and 1/2". Format(2) To delete or purge data from a hard disk or drive. |
| Frame |
The basic unit of a moving picture. A frame contains 625 lines (PAL) or 525 lines (NTSC). |
| Frame store |
An electronic device used to capture and digitally store a video image. It can be an independent unit or in built in other equipment like fast scan video transmitters or video motion detectors. |
| Gamma correction |
A correction built into the surveillance camera to adjust for the brightness characteristic of the monitor. The gamma value ranges from 0.6 to 1.0. |
| Gen. Lock (See Ext. Sync) |
To synchronize one piece of equipment to the sync pulses of another. |
| Ghost |
A shadowy or weak image in the received picture, offset to either the right or to the left of the primary image. |
| GHz may refer Gigahertz (units of frequency). MHz (MegaHertZ) |
One million cycles per second. It is used to measure the transmission speed of electronic devices, including channels, buses and the computer's internal clock. A one-megahertz clock (1 MHz) means some number of bits (16, 32, 64, etc.) are manipulated one million times per second. A one-gigahertz clock (1 GHz) means one billion times. MHz and GHz are used to measure the speed of the CPU. For example, a 1.6 GHz computer processes data internally (calculates, compares, etc.) twice as fast as an 800 MHz machine. However, the doubled clock speed of the CPU does not mean twice as much finished work gets done in the same time frame. Internal cache design, bus speed, disk speed, network speed and software design all contribute to the computer's overall processing speed and performance (overall throughput). MHz and GHz Are the Heartbeat when referencing CPU speed, the megahertz and gigahertz ratings are really the heartbeat of the computer, providing the raw, steady pulses that energize the circuits. If you know German, it's easy to remember this. The word "Herz," pronounced "hayrtz," means heart. This was a coincidence, because in 1883, Heinrich Hertz identified electromagnetic waves. |
| Gigabyte (GB) |
1,024 megabytes or 1 billion characters of information. Also see Megabyte. |
| Gotcha Spy |
Call us toll free at (877)-GOTCHA2 |
| Gray Scale |
The number of variations from white to gray to black. |
| Ground |
An electrical connection point that is common to either a metal chassis, a terminal, or a ground bus. |
| Ground Loop |
Effects video pictures in the form of a black shadow bar across the screen or as tearing in the top corner of a picture. Caused by different earth potentials in a system. |
| GUI Graphical User Interface |
Interfaces the computer with the matrix switcher. Hot areas on the computer screen can be programmed to activate a matrix switcher, VCR etc. It helps in making the cctv (closed circuit television) system more user friendly. |
| H.264 |
(See video file formats) |
| Hardwired |
Method of controlling camera points using multi-core cable. |
| Hertz |
A unit of measuring frequency. 1 Hertz = 1 cycle per second. |
| Hidden Camera |
A hidden camera is a still or video camera used to film people without their knowledge. The camera is "hidden" because it is either not visible to the subject being filmed, or is disguised as another object. Hidden cameras have become popular for household surveillance, and can be built into common household objects such as smoke detectors, clock radios, motion detectors, ball caps, plants, and cellphones. Hidden cameras may also be used commercially or industrially as security cameras. A hidden camera can be wired or wireless. The former will be connected to a TV, VCR, or DVR, whereas a wireless hidden camera can be used to transmit a video signal to a receiver within a small radius (up to a few hundred feet).
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| Historical GPS |
or one of our GPS products known as the "GPS Historical Logger A Historical GPS Logger will STORE the tracking / mapping infromation internally until the GPS unit is retrived and downloaded to a computer and reviewed as a computer file. Informations such as time, dates, addresses, full map route and speed can all be viewed upon downloading the GPS device. Historical means past tense, an event that has happend yesterday, or a few moments ago. www.gotchaspy.com |
| Horizontal Resolution |
he number of vertical lines which can be resolved in a picture. It depends upon the number of pixels in a chip. |
| Hz (Hertz) |
Cycles per second. |
| 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. |
| I.S.D.N. (Integrated Services Digital Network) |
Digital phone lines from which allow transmission of video signals via fastscan at speeds of 128Kb/second; used with terminal adapters. |
| Illuminance |
The amount of luminous flux falling on a surface area and is measured in lux or foot candle. |
| 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 Device (Imager) |
The detector in the camera, either a tube or a CCD solid state device. |
| Image Resolution |
Image resolution describes the detail an image holds. The term applies equally to digital images, film images, and other types of images. Higher resolution means more image detail. Image resolution can be measured in various ways. Basically, resolution quantifies how close lines can be to each other and still be visibly resolved. Resolution units can be tied to physical sizes (e.g. lines per mm, lines per inch) or to the overall size of a picture (lines per picture , also known simply as lines, or TV lines). Furthermore, line pairs are often used instead of lines. A line pair is a pair of adjacent dark and light lines, while lines counts both dark lines and light lines. A resolution of 10 lines per millimeter means 5 dark lines alternating with 5 light lines, or 5 line pairs per millimeter. Photographic lens and film resolution are most often quoted in line pairs per millimeter. |
| Impedance |
The input and output characteristic of any electrical system and is measured in ohms. For maximum signal transfer, the input and output impedance should be the same. cctv (closed circuit television) systems have a 75 ohm impedance. |
| Index Of Refraction |
ratio between the angle of incidence to the angle of refraction of light. It depends upon the density of a medium. A denser medium will have a higher index of refraction and will also bend the light more. |
| Infrared Illumination |
When a low light view 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. |
| Infrared Illuminator |
A type of light source which emits light in the infrared frequency range. |
| Infrared link |
A type of transmission medium in which video, data or audio are modulated with infrared light and then transmitted into air to a receiver in a remote location. |
| Infrared Radiation |
Electromagnetic radiation with a wavelength of more than 750 nanometers. It is not visible to the human eye. |
| Insertion Loss |
The signal strength loss that occurs when a piece of equipment is inserted into a line. |
| Intensifier |
An electronic device that creates an output image brighter than the input (original) image. Optical amplifier. |
| Interference |
xternal energy which interferes with an electrical signal causing picture distortions. |
| Interlace |
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. |
| Interlacing |
The process of combining even and odd fields to form a frame. |
| Internal Sync (Crystal Controlled) |
A camera that generates its sync pulses without reference to any other source. Normally using a crystal controlled oscillator. |
| IP - Internet protocal |
IP is the usual abbreviation for Internet Protocol. It is also a common abbreviation for different things in different fields.The Internet Protocol (IP) is a protocol used for communicating data across a packet-switchedinternetwork using the Internet Protocol Suite, also referred to as TCP/IP. IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering distinguished protocol datagrams (packets) from the source host to the destination host solely based on their addresses. For this purpose the Internet Protocol defines addressing methods and structures for datagram encapsulation. The first major version of addressing structure, now referred to as Internet Protocol Version 4 (IPv4) is still the dominant protocol of the Internet, although the successor, Internet Protocol Version 6 (IPv6) is being deployed actively worldwide. |
| IP Address |
The Internet Protocol address; a unique numeric address such as 123.231.32.2 Also see Static IP and Dynamic IP. |
| IP Camera |
IP Video Surveillance Camera, IP cam IP cameras are Closed-circuit television (CCTV) cameras that utilize Internet Protocol, a network to transmit image data and control signals over a Fast Ethernet link. As such, IP cameras are also commonly referred to as network cameras. IP cameras are primarily used for surveillance in the same manner as analog closed-circuit television. A number of IP cameras are normally deployed together with a digital video recorder (DVR) or a network video recorder (NVR) to form a video surveillance system. The terms IP camera and network camera are most commonly used to refer to surveillance cameras with a Fast Ethernet interface. In this context, the term IP camera does not include GigE vision camera, which is a machine vision camera with a Gigabit Ethernet interface. |
| Iris |
A part of a lens that can be adjusted to vary the amount of light passing through the lens and falling on the CCD chip. |
| ISDN Integrated Services Digital Network |
A type of telephone network which accepts digital signals. |
| Jpeg |
In computing, JPEG (pronounced JAY-peg) is a commonly used method of compression for photographic images. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality. JPEG compression is used in a number of image file formats. JPEG/Exif is the most common image format used by digital cameras and other photographic image capture devices; along with JPEG/JFIF, it is the most common format for storing and transmitting photographic images on the World Wide Web. These format variations are often not distinguished, and are simply called JPEG. |
| Key Stroke Logger |
An hardware or software device that catalogues any and all input that a user enters during the coarse of a computer session. Offers a complete and thorough trace of activity so that no questions can arise about computer related conduct or circumstance. Keystroke logging "key-loggers" Keystroke logging "Keylogger" (often called keylogging) is a method of capturing and recording user keystrokes. The technique and name came from before the era of the graphical user interface; loggers nowadays would expect to capture mouse operations and screenshots. Keylogging can be useful to determine sources of errors in computer systems, to study how users interact and access with systems, and is sometimes used to measure employee productivity on certain clerical tasks. Such systems are also highly useful for both law enforcement and law - breaking - for instance, providing a means to obtain passwords or encryption keys and thus bypassing other security measures. Keyloggers are widely available on the Internet. There are currently two types of keylogging methods, hardware and software based. |
| LAN - ( Local Area Network) |
Connects different computers so that they can communicate with each other. Different connection protocols are possible. |
| LCD |
Liquid Crystal Display Products that are generaly flat screen TV's, computer monitors or small "flat" screen monitors
A liquid crystal display (LCD) is an electronically-modulated optical device shaped into a thin, flat panel made up of any number of color or monochromepixels filled with liquid crystals and arrayed in front of a light source (backlight) or reflector. It is often utilized in battery-powered electronic devices because it uses very small amounts of electric power. A comprehensive classification of the various types and electro-optical modes of LCDs is provided in the article LCD classification. |
| Lead Acid Battery |
A type of DC power source which is similar to a car battery. It is generally used in temporary installations with DC surveillance cameras. |
| Lens |
(Lens can refer to) In optics Lens (optics), an optical element which converges or diverges light |
| Lens calculator |
A calculator provided by many lens manufacturers to help calculate the focal length of the lens that will provide the required scene. |
| 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. |
| 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. |
| Light |
Electromagnetic radiation between 400 nm and 750 nm which is detectable by the human eye. |
| Light Sensor |
A device which is activated by a pre-set amount of light falling on it. It can be used to switch infrared illuminators On / Off. |
| Light-Emitting Diode ( LED ) |
Red, green and blue LEDs of the 5mm type A light-emitting diode (LED), is an electronic light source. The LED was invented in the early 20th century, and introduced as a practical electronic component in 1962. All early devices emitted low-intensity red light, but modern LEDs are available across the visible, ultraviolet and infra red wavelengths, with very high brightness. LEDs are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. The LED is usually small in area (less than 1 mm2) with integrated optical components to shape its radiation pattern and assist in reflection. LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise current and heat management than traditional light sources. Applications of LEDs are diverse. They are used as low-energy replacements for traditional light sources in well-established applications such as indicators and automotive lighting. The compact size of LEDs has allowed new text and video displays and sensors to be developed. |
| Line |
he basic unit of a frame or field containing the charge which is proportional to the light falling at various points on the scanning line. |
| 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). |
| Lithium-ion polymer battery |
Lithium-ion polymer batteries, polymer lithium ion, or more commonly lithium polymer batteries (abbreviated Li-poly, Li-Pol, LiPo, LIP, PLI or LiP) are rechargeable batteries which have technologically evolved from lithium-ion batteries. Ultimately, the lithium-salt electrolyte is not held in an organic solvent as in the lithium-ion design, but in a solid polymer composite such as polyethylene oxide or polyacrylonitrile. The advantages of Li-poly over the lithium-ion design include lower cost manufacturing and being more robust to physical damage. Lithium-ion polymer batteries started appearing in consumer electronics around 1996. |
| Looping |
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. |
| Lumen |
A measurement of light which indicates the amount of light radiated by a one candela light source. |
| Luminance (Y) |
The part of a video signal that consists of the monochrome data. |
| Luminance signal |
hat part of the video signal which contains the information on the brightness of the picture. |
| Luminous flux |
The rate of flow of light. |
| Lux |
An international unit of illumination. It is the amount of uniform light falling on an area of 1 square meter and is measured in lumen per sq. meter. A unit measuring the intensity of light. The light of a full moon is about 0.1 lux, while bright sunlight is about 100,000 lux. Basically, the lower the rating the better the camera performs at night. 1.0 lux in video means light level of a candle light. l Lux approximately equals to 10 foot-candles (1 Lux = 10.764 fc). International System (Sl) unit of illumination in which the meter is the unit of length. One lux equals one lumen per square meter. |
| Manual Iris Lens |
A lens with a manual adjustment to set the iris opening (F stop) in a fixed position. Generally used for fixed lighting applications. |
| Matrix Switcher |
A switcher able to route any of its camera inputs to any of its monitor outputs; a name usually reserved for large systems, that often includes telemetry control. |
| MATV |
Short for Multiple Access Television. The method for distributing RF TV signals by broadcasting them through the air. |
| Mechanical Focus (Back-Focus, Racking) |
The mechanical aligning of the imaging device with the focal point of the lens; most important on zoom lenses to ensure the image stays in focus throughout the zoom range. |
| Megabyte (MB) |
1,048,576 bytes or 1,024 kilobytes. Used to measure computer memory. Sometimes used to mean 1 million bytes or 1,024,000 bytes (1,000 kilobytes). Also see Gigabyte. |
| Microwave |
Radio frequencies between 1 - 30 GHz used for video transmission over medium/long distance. |
| Minimum Object Distance (M.O.D.) |
The closest distance a given lens will be able to focus upon an object. This is measured from the vertex (front) of the lens to the object. Wide angle lenses generally have a smaller M.O.D. than large focal length lenses. |
| Minimum Scene illumination |
A specification shown in most surveillance camera data sheets and indicates the minimum light required at the scene to provide a reasonable picture on the monitor. |
| Modem |
Derived from the term 'modulator -demodulator' and is used to convert a digital signal into an analogue signal so that it can be transmitted via the PSTN telephone network |
| Modulate |
To change or vary some parameter such as varying the amplitude of a signal for amplitude modulation or the frequency of a signal for frequency modulation. A modulator is the circuit that modulates the signal. |
| MONITOR |
A unit of equipment that displays on the face of a picture tube the images detected and transmitted by a television camera. |
| Monochrome |
Having only one color. In television it is black and white. |
| Motion detection |
Motion detection is the action of sensing physical movement in a given area. Motion can be detected by measuring change in speed or vector of an object or objects in the field of view. This can be achieved either by mechanical devices that physically interact with the field or by electronic devices that quantifies and measures changes in the given environment. When motion detection is accomplished by natural organisms, it is called motion perception. |
| MPEG |
MPEG is a video compression method commonly used in digital recording. MPEG-1 is a standard for CD-ROM video and audio. MPEG-2 is a standard for full-screen, broadcast quality video.MPEG-4 is a standard for video telephony. |
| Multiplex (Time Multiplex) |
Using one carrier to send more than one signal |
| MUX |
A multiplexer. |
| N/D (Neutral Density) |
A filter that attenuates light equally over the whole visible spectrum. |
| Nanny cam |
A hidden video camera that has been covertly or secretly installed within a common household object. A nanny cam is usually used to secretly monitor and record the activities of home caregivers, hence the name "Nanny Cam" although it can be also be used to clandestinely record any activity and work as a security device. The receiver can be located at the VCR or DVR recording device, can be a portable receiver-screen or can be an internet broadband connection. It can be connected to a VCR or DVR, either with:
A cable
Or by a wireless transmitter, located in the nanny cam, and a wireless receiver.
There have been many news stories centered around a hidden camera that has recorded a nanny in the act of abusing a child. They can also be used to prove the innocence of a suspected abuser. A nanny cam can be purchased in many forms. The camera can be hidden inside a child's teddy bear, a wall clock, a clock radio, or even a plant or tissue box. For convenience, most nanny cams use built-in transmitters to transmit their video and sound to a recording device located in another room or floor. |
| Neutral density filter |
A type of filter used with lenses which reduces light of all wavelengths equally. |
| Night Vision |
A device that has the ability to see in a dark environment. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range. |
| Noise |
An unwanted signal generated by every electronic component. The noise in a video signal causes a grainy or snowy effect on the image. |
| NTSC |
Color TV system used in the USA. CCTV (National Television Standards Committee. See E.I.A.) |
| NTSC National Television System Committee |
A color television system and the standard used in the USA and Japan. NTSC has 525 horizontal scanning lines and 60 fields per sec. |
| Ohms |
A unit for measuring resistance or impedance of any electrical device. |
| Omni directional transmitter |
A transmitter which sends the signal in all directions. |
| Optical Filter |
A type of filter used in optics which selectively allows light of different frequencies to pass through. |
| Oscilloscope |
A device which visually displays the wave form of any electrical signal on a screen. In cctv (closed circuit television), it is used trouble shooting and making adjustments of various components. |
| PAL |
Color TV system used in the UK (Phase Alternate Line. See CCIR) |
| PAL - Phase Alternating Line |
A color television system and the standard used in Western Europe, Australia, parts of Africa and Asia. PAL has 625 horizontal scanning lines and 50 fields per sec. USA standard is NTSC |
| Pan |
ide-to-side movement of a camera (on a horizontal axis). |
| Passive |
A non powered element of a system. |
| Peak-To-Peak |
The amplitude difference between the most positive and the most negative excursions of a signal. |
| Peripheral |
An optional device that can enhance a CCTV system, for example, a multiplexer, VCR, photo printer, etc. |
| Persistency of vision |
The retina of the human eye retains an image for 40ms. This characteristic is called persistency of vision and is used to make a picture appear continuous by flashing images on the retina at a rate faster than 24 images per sec. |
| Phase Adjustable (See Line Lock) |
The ability to delay the line locking process, so as to align cameras fed from A.C. voltages on different phases. |
| Phase adjustment |
A surveillance camera adjustment used to synchronize all the surveillance cameras in the system by altering the phase of the power supply. |
| Phase angle |
The angle at any point of the sine wave of an AC power supply and varies between 0 to 360 degrees over a cycle. |
| Phosphor |
A material which is capable of emitting light. It is used in fluorescent lamps, monitors etc. The duration of the emission depends on the type of phosphor. |
| Photocell |
Automatically switches on the infra-red lights when light levels fall to a preset level. |
| Photon |
The basic unit of light. |
| PI |
Private Investigator |
| Picture tearing |
ccurs when the horizontal sync pulses are distorted or lost and the monitor is unable to latch on to them causing the horizontal lines to be displaced in a random manner. This is seen as a tearing of the picture on the monitor. |
| Pincushion distortion |
A type of distortion caused due to non uniform scanning in the monitor which makes the picture to bulge inwards. |
| Pinhole Camera |
A small lens with a diameter of 1.5mm to 9.5mm used for covert surveillance. |
| Pinhole Lens |
Lens used for applications where the camera/lens must be hidden. Front of lens has a small opening to allow the lens to view an entire room through a small hole in a wall. |
| Pip |
Picture in picture. |
| PIR Passive infrared sensor |
Passive InfraRed sensor (PIR sensor) is an electronic device that measures infrared (IR) light radiating from objects in its field of view. PIR sensors are often used in the construction of PIR-based motion detectors. Apparent motion is detected when an infrared source with one temperature, such as a human, passes in front of an infrared source with another temperature, such as a wall. |
| Pixel |
icture element. The smallest cell or area of a CCD chip capable of displaying detail on a screen. The greater the number of pixels, the higher the resolution. |
| Pixel (picture element) |
he basic unit of a CCD chip which accumulates charge depending upon the amount of light falling upon it. A typical CCD chip has over 300,000 pixels. |
| Polarizer |
A type of filter which reduces glare by intercepting reflected light from surfaces like water , glass. etc. |
| Polycarbonate glass |
A type of toughened glass which can be used in housings for use in high vandal areas. |
| Polyethylene |
A type of plastic used to make outer jackets for cables. |
| Potentiometer |
An electronic component in which the resistance can be changed by a movable contact point. It is used in pan/tilt heads and zoom lenses to record pre-set positions. |
| Power line interference |
type of interference caused by main power lines and usually seen as horizontal bands on the monitor. |
| Pre set |
Term used in cctv (closed circuit television) to define pre determined positions of a pan/tilt head and zoom lens. |
| Preamplifier (Preamp) |
A Type of amplifier used to increase the output of a low level source allowing the signal to be processed by other devices. |
| Presets |
The pre-positioning of pan, tilt and zoom cameras by the use of potentiometers in the moving parts of the camera head. These allow the control equipment to store and move to a set reference point when the controller dictates or when an alarm exists. |
| Pressure mat |
A device which is activated by the application of pressure and is used to open doors, gates etc. It can also activate the switcher to bring the nominated surveillance camera up for extended viewing. |
| Primary Color |
A basic color which cannot be obtained by mixing other colors. Red, green and blue are the three primary colors which can be mixed to produce other colors. |
| PSTN |
Standard phone lines used to transmit fastscan pictures via modems. (Public Switched Telephone Network) |
| PSTN Public Switched Telephone Network |
A type of analogue telephone network currently in use all over the world. |
| PTZ controller |
A device used to control the movement of the pan/tilt head and zoom lens from a remote location. |
| Quad |
A device which uses digital video to display pictures from 4 surveillance cameras on a single monitor. |
| Rack Mount |
An industrial standard housing 19" wide, its height is measured in units of 1.75". |
| Radio frequency |
Radio frequency (RF) is a frequency or rate of oscillation within the range of about 3 Hz to 300 GHz. This range corresponds to frequency of alternating currentelectrical signals used to produce and detect radio waves. Since most of this range is beyond the vibration rate that most mechanical systems can respond to, RF usually refers to oscillations in electrical circuits. |
| Radio Frequency (R.F.) |
Signals with a repetition rate above audible range, but below the frequencies associated 4 With heat and light. |
| Radio-frequency identification (RFID) |
Radio-frequency identification (RFID) is the use of an object (typically referred to as an RFID tag) applied to or incorporated into a product, animal, or person for the purpose of identification and tracking using radio waves. Some tags can be read from several meters away and beyond the line of sight of the reader. |
| RAID |
edundant Arrays of Independent Disks. The use of two or more disk drives instead of one disk, which provides better disk performance, error recovery, and fault tolerance, and includes interleaved storage techniques and mirroring of important data. |
| Random Interlace |
A scanning technique commonly used in CCTV systems in which there is no external control over the scanning process. That is, there is no fixed relationship between adjacent lines and successive fields. |
| Range Finder |
Used to determine the focal length needed and what the picture will look like on the monitor. The user looks through the device and adjusts the range finder to the desired picture. Numbers on the outside of the range finder indicate the focal length needed. |
| Raster |
The rectangular pattern of scanning lines upon which the picture is produced. The illuminated face of the TV monitor without the video information present. |
| Read out time |
The time taken to read the charge from the pixels in a CCD chip. |
| Real time video |
A picture with more than 24 frames per sec and therefore looks continuous. |
| Real-time recording |
For digital video, 30 frames-per-second per camera allows smooth video without choppy or delayed images while reviewing video. |
| Receiver driver |
A part of the matrix switcher placed at the surveillance camera point and connected to the main switcher by a twisted pair cable. It is used to decode the incoming control signals for the Pan Tilt Zoom functions. |
| Rechargeable battery |
A rechargeable lithium polymer battery. A rechargeable battery, also known as a storage battery, is technically a group of two or more secondary cells, such as laptop batteries containing six individual cells. However, they are often used to refer to a single cell, such as a NiMH AA battery. These batteries can be restored to full charge by the application of electrical energy, such as through a battery charger. In other words, they are batteries in which the electrochemicalreaction that releases energy is readily rechargeable. They come in many different designs using different chemicals. Commonly used secondary cell ("rechargeable battery") chemistries are lead acid, nickel cadmium (NiCd), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer). Rechargeable batteries can offer economic and environmental benefits compared to disposable batteries. Some rechargeable battery types are available in the same sizes as disposable types (eg. AA, AAA, CR123A). While the rechargeable cells have a higher initial cost, rechargeable batteries can be recharged many times. Proper selection of a rechargeable battery system can reduce toxic materials sent to landfills compared to an equivalent series of disposable batteries. For example, some manufacturers of NiMH rechargeable batteries claim a service life of 100-1000 charge cycles for their batteries. |
| Reed switch |
type of alarm activated when the contact is opened or closed . It is widely used with doors, windows, roller shutters etc. and can also activate a switcher to bring the nominated surveillance camera up for extended viewing. |
| Reflected Light |
The scene brightness or the light being reflected from a scene. |
| Regulated power supply |
A type of DC power supply in which the ripple factor is minimal. |
| Remote head surveillance camera |
A type of surveillance camera in which the CCD chip is separated from the surveillance camera body by cable. It is used in applications where the amount of space is limited. |
| Remote surveillance |
The ability to view a camera image that is located remotely, where the video image is transmitted over a phone line, the Internet or wireless. |
| Resolution |
A measure of picture definition and clarity and is represented by number of lines. Greater the number of lines, higher the resolution. |
| RESOLUTION (HORIZONTAL) |
The amount of resolvable detail in the horizontal direction in a picture. It is usually expressed as the number of distinct vertical lines, alternately black and white, which can be seen in a distance equal to picture . A measure of the ability of the camera or monitor to reproduce detail. The higher the resolution the clearer the image. |
| Resolution (VERTICAL) |
The amount of resolvable detail in the vertical direction in a picture. It is usually expressed as the number of distinct horizontal lines, alternately black and white, which can theoretically be seen in a picture. A measure of the ability of the camera or monitor to reproduce detail. The higher the resolution the clearer the image. |
| RG-11 |
A type of coaxial cable with a thicker center core and used for transmission of video signals up to 550m. |
| RG-59 |
A type of coaxial cable used for transmission of video signals up to 230m. It is the most popular cable used in cctv (closed circuit television). |
| Ripple factor |
The amplitude variation present in a DC power supply due to insufficient filtering . A large variation can damage a DC surveillance camera. |
| Roll |
A loss of vertical sync which causes the picture to move up or down on the TV screen. |
| RS-232 |
A communication protocol used for communication between microprocessor based devices.
|
| Rs232 |
A commonly used computer serial interface. |
| S-VHS Super VHS |
A type of video format in which the illuminance and chrominance signals are sent separately resulting in improved picture quality. |
| S.E.C.A.M. (See CCIR) |
New format high resolution VHS video recorders, capable of giving greatly improved picture if all features are used. VHS compatible. |
| S.V.H.S. (Super Video Home System) |
New format high resolution VHS video recorders, capable of giving greatly improved picture if all features are used. VHS compatible. |
| S/N Ratio (Signal To Noise Ratio) |
Measure of noise levels of a video signal; the higher the number the better. |
| Salvo switching |
A feature in matrix switchers. On command from the matrix switcher or an alarm event. a group of surveillance cameras can be switched simultaneously onto a group of monitors. |
| Saturation (Color) |
The vividness of a color. It is directly related to the amplitude of the chrominance signal. |
| Scanner |
A pan only unit. |
| Scanning |
The rapid movement of the election beam in a pickup device of a camera or in the CRT of a television receiver. It is formatted in a line-for-line manner across the photo sensitive surface which produces or reproduces the video picture. |
| Screenshot |
A screenshot, screen capture, or screen dump is an image taken by the computer to record the visible items displayed on the monitor or another visual output device. Usually this is a digital image taken by the host operating system or software running on the computer device, but it can also be a capture made by a camera or a device intercepting the video output of the computer. Screenshots, screen dumps, or screen captures can be used to demonstrate a program, a particular problem a user might be having or generally when computer output needs to be shown to others or archived, or to simply show off what you do on your computer to others. All three terms are often used interchangeably; however, some people distinguish between them as follows: Screenshot
Outputting the entire screen in a common bitmap image format such as BMP, PNG, or JPEG. Screen dump
The display system dumps what it is using internally upon request, such as XWD X Window Dump image data in the case of X11 or PNG in the case of Mac OS X. Screen capture (screencaps) Capturing the screen over an extended period of time to form a video file. |
| SCSI |
Small Computer Systems Interface (Pronounced "scuzzy".) A ultra high-speed interface that can connect to computer devices such as a hard drive or CD-Rom. A SCSI channel can connect up to seven devices. |
| SD Card - "Secure Digital card" Secure Digital (SD) |
A non-volatilememory card format developed by Matsushita, SanDisk, and Toshiba for use in portable devices. Today it is widely used in digital cameras, handheld computers, PDAs, Media Players, mobile phones, GPS receivers, and video game consoles. Standard SD card capacities range from 4 MB to 2 GB, and for high capacity SDHC cards from 4 GB to 32 GB as of 2008. The SDXC (eXtended Capacity), a new specification announced at the 2009 CES, will allow for 2 TB capacity cards. The format has proven to be very popular. A change in the format, however, while allowing capacities greater than 4 GB (SDHC), has created compatibility issues with older devices that cannot read the new format. The fact that SDHC format cards have the same physical shape and form factor as the older format has caused considerable confusion for consumers.SDHC cards require SDHC-capable device firmware generally not found with older devices. |
| SECAM Sequential Coluleur A'Memorie |
A color television system used in France and a few other countries. |
| Sensitivity |
A camera's ability to reproduce a given scene with a given amount of light. Usually expressed in foot-candles or lux. |
| Sensitivity of a surveillance camera |
The minimum light level required at the CCD chip which will generate a usable video picture. It is measured in lux. |
| Sensor |
A device that indicates a change of state in response to an event or stimulus. See Image Device. |
| Sequential switcher |
A type of switcher that allows multiple surveillance cameras to be displayed or recorded one at a time. |
| Sequential Switchers |
Are commonly used devices in small to medium sized CCTV systems. The sequential switcher alternates the displayed video image from one camera to the next. However, with sequential switching not all cameras can be viewed simultaneously. |
| Shield |
A copper braid which covers the dielectric and center core of a coaxial cable. It protects the video signal from EMI. |
| Shutter speed |
The speed at which the charge is read out from the CCD chip. The factory setting is 1/50 sec (PAL) or 1/60 sec (NTSC) and can be increased up to 1/100,000 sec depending upon the surveillance camera brand. It can be changed by using dip switches or in some cases by the in built menu in the surveillance camera. |
| Signal loss |
A reduction in signal strength expressed in decibels. |
| Signal to noise ratio |
It is the ratio between the signal voltage and the noise voltage generated by an electronic circuit. It is measured in decibels (dB). |
| Silicon wafer |
A semiconductor material on which the CCD chips are etched. |
| Simplex |
A system which can handle only one channel of video, audio or data signal. |
| Simplex (Multiplexer) |
A multiplexer with 1 frame store that can either time multiplex records or show multi-screen pictures in live or play back. It cannot record the multiplexer pictures whilst showing multi-screen pictures. |
| Single mode cable |
An expensive type of fiber optic cable with a narrow glass core which allows only a single path for signal transmission. |
| SMS |
xting text messaging Received SMS on a Motorola RAZR mobile phone E.161, the most common mobile keypad alphabet layout Short Message Service (SMS) is a communication service standardized in the GSM mobile communication system, using standardized communications protocols allowing the interchange of short text messages between mobile telephone devices. SMS text messaging is the most widely used data application on the planet, with 2.4 billion active users, or 74% of all mobile phone subscribers sending and receiving text messages on their phones.[citation needed] The SMS technology has facilitated the development and growth of text messaging. The connection between the phenomenon of text messaging and the underlying technology is so great that in parts of the world the term "SMS" is used as a synonym for a text message or the act of sending a text message, even when a different protocol is being used. SMS as used on modern handsets was originally defined as part of the GSM series of standards in 1985 as a means of sending messages of up to 160 characters (including spaces), to and from GSM mobile handsets. Since then, support for the service has expanded to include alternative mobile standards such as ANSI CDMA networks and Digital AMPS, as well as satellite and landline networks.[citation needed] Most SMS messages are mobile-to-mobile text messages, though the standard supports other types of broadcast messaging as well. |
| Snow |
A fault in the picture, appearing as small dots on the monitor and is caused by heavy noise in the video signal. |
| Sodium vapor lamp |
type of artificial light source which is very efficient and uses sodium vapor to produce a yellow-orange light. |
| Solving Focus Shift |
Filtering techniques can be applied to solve the problem of focus shift under active infrared lighting. Cameras behave differently under visible light and infrared light, with one of the chief differences being focal properties. Day-night mechanical filters solve this problem by blocking IR light from during the day and optimizing IR response during the night. The result is a sharply focused image in day and dark conditions. |
| Spectral response |
The sensitivity of a device to different light frequencies. |
| Spot Filter |
A small insert used in a lens to increase the f-stop range of the lens. |
| SPY - Espionage "Spy" and "Secret agent" |
spionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, as the legitimate holder of the information may change plans or take other countermeasures once it is known that the information is in unauthorized hands. See clandestine HUMINT for the basic concepts of such information collection, and subordinate articles such as clandestine HUMINT operational techniques and clandestine HUMINT asset recruiting for discussions of the "tradecraft" used to collect this information. |
| Standard angle lens |
A type of lens which provides a view having the same proportions as seen by the human eye. It has a magnification ratio of 1. |
| Static IP Address |
A Static or Dedicated IP address is a type of account from an ISP where your computer or network is assigned the same constant IP Address at all times. Also see IP Address and Dynamic IP. |
| Step down transformer |
A transformer used in power supplies to step down or lower the main line voltage. The ratio between the number of turns of the primary coil to the secondary coil determines the step down voltage. |
| Stranded cable |
A type of cable in which a number of wires enclosed in an outer jacket are used to transmit the electrical signal. |
| Sunshield |
A movable accessory placed on top of outdoor housings to prevent direct light falling on the surveillance camera. |
| Surveillance camera |
An electronic device which converts light into an electrical signal. |
| Surveillance camera controller |
Controls the different functions of the pan/tilt head and the zoom lens. It is also known as the PTZ controller. |
| Surveillance System |
A mechanical or electronic system or device that enables continuous or periodic video recording, observing or monitoring of personal information about individuals in open, public spaces (including streets, highways, parks), public buildings (including provincial and local government buildings, libraries, health care facilities, public housing and educational institutions) or public transportation, including school and municipal transit buses or other similar vehicles. |
| Switcher |
A device used to switch the video signals from two or more cameras on a monitor. |
| Sync |
Abbreviation for synchronization. Electronic pulses that are inserted in to video signal for the purpose of assembling the picture information in the correct position. |
| Sync generator |
A device which generates sync pulses which are then used to synchronize surveillance cameras. |
| Synchronization |
A process which ensures that the formation of frames in a multi surveillance camera system start at the same time. There are different ways to achieve surveillance camera synchronization. |
| Tearing |
A picture condition in which horizontal lines are displaced in an irregular manner. |
| Telemetry |
A system utilizing control code transmitters and receivers. These use the video cable or a simple twisted pair cable to send their information. |
| Telephoto |
A lens used to produce a larger image of a distant object. |
| Telephoto lens |
A type of lens used to view far away objects. It has a magnification ratio > 1. |
| Terminal strip |
A clamp used to secure the cables firmly to the housing base. |
| Terminated (75 Ohm Terminated) |
Video input of a piece of CCTV equipment, wired to be the last in a particular video line. |
| Test pattern generator |
A device which generates a test pattern to be used to adjust and test the monitor. |
| Thermal paper |
A special type of paper used in video printers. |
| Tilt |
The up and down tilting movement of a camera. To elevate or depress the vertical angle of view. |
| Time and Date Stamp |
A watermarked (embedded) time and date in video or images. |
| Time based switching |
A feature in matrix switchers which allows various programmed surveillance camera sequences to be initiated at various times. |
| Time lapse VCR |
A type of video cassette recorder especially designed for cctv (closed circuit television) requirements. It allows more recording time on a single video tape by not recording all the frames. |
| Time Zone |
Time intervals during which an activity is permitted. |
| Time-Lapse VCR |
Video recorder that can record frames with pauses between them thereby extending the time that a standard length tape will last. |
| Time/date generator |
A device which generates time and a date superimposes it on the video signal. |
| Timebase Corrector (T.B.C.) |
Electronic circuit that aligns unsynchronized video signals before signal processing. Used in multiplexers and quad splitters. |
| Touch screen |
type of modern monitor screen. Action can be initiated by touching the relevant point on the monitor screen. |
| Transmitter-receiver |
An electronic device that transmits and receives communications signals. |
| Trapezoidal distortion |
A type of distortion in the monitor caused due to non uniform scanning which makes the scanning lines look wider at the top than at the bottom of the monitor. |
| Triaxial cable |
A type of co axial cable which has two layers of shield to provide better protection against EMI. |
| Triplex (TM) |
Multiplexer feature that gives you the ability to simultaneously view both playback and live cameras within the same multi-screen, while still encoding. |
| TSC National Television Standards Council |
A video format standard used in North America, Japan, and parts of South America. Abbreviation for National Television Systems Committee. A committee that worked with the FCC in formulating standards for the present day United States color television system. |
| TVL |
The maximum number of changes between light and dark on a picture across 3/4 of the width dictates the resolution of a CCTV product, measured in TVL. (Television Lines - Resolution) |
| Twisted Pair |
A cable, often screened, that consists of two conductors twisted together along their length. |
| Twisted pair cable |
A type of balanced cable in which a pair of cables are twisted and the signal is divided between them. |
| Two speed recorder |
A type of domestic use VCR which has two speeds of recording/playback, standard and long play. The long play mode doubles the recording time of a standard tape. |
| Ultraviolet |
Electromagnetic radiation with a wavelength of less than 400 nm and is not visible to the human eye. |
| Unbalanced cable |
A type of cable in which the ends of the shields are grounded to different equipment with possibly varying ground potential. This unbalanced set up can give rise to ground loop currents and EMI induction. |
| Unterminated (Hi-Z) |
Video input of a piece of CCTV equipment, wired so as to allow the video signal to be fed to further equipment. Does not necessarily include extra sockets for the extra coaxial cables. |
| UPS Uninterruptible Power Supply |
Stores electricity and supplies power to a cctv (closed circuit television) system during a power failure. |
| Usable video |
The minimum video signal specified in the surveillance camera data sheet to generate an acceptable picture on the monitor. It is usually measured as a percentage of the full video. |
| USB - USB PORT - Universal Serial Bus |
A USB Series plug, the most common USB plug The USB trident logo In information technology, Universal Serial Bus (USB) is a serialbus standard to connect devices to a host computer. USB was designed to allow many peripherals to be connected using a single standardized interface socket and to improve plug and play capabilities by allowing hot swapping; that is, by allowing devices to be connected and disconnected without rebooting the computer or turning off the device. Other convenient features include providing power to low-consumption devices, eliminating the need for an external power supply; and allowing many devices to be used without requiring manufacturer-specific device drivers to be installed. USB is intended to replace many varieties of serial and parallel ports. USB can connect computer peripherals such as mice, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, flash drives, and external hard drives. For many of those devices, USB has become the standard connection method. USB was designed for personal computers, but it has become commonplace on other devices such as PDAs and video game consoles, and as a power cord between a device and an AC adapter plugged into a wall plug for charging. As of 2008, there are about 2 billion USB devices sold per year, and about 6 billion total sold to date. The design of USB is standardized by the USB Implementers Forum (USB-IF), an industry standards body incorporating leading companies from the computer and electronics industries. Notable members have included Agere (now merged with LSI Corporation), Apple Inc., Hewlett-Packard, Intel, NEC, and Microsoft. |
| Varifocal |
See Zoom Lens. Usually not motorized (manual). |
| Varifocal lens |
A type of manual zoom lens with a small zoom ratio (ranging between 4mm to 12mm depending on brand). It is used when the focal length of the lens needs to be fine tuned to meet the requirements of the actual scene. |
| VCR |
A device that records video images on tape. |
| Vertical Interval Switching |
Sequential switchers waiting until the current field has finished before they display the next camera, even though the dwell time has elapsed. |
| Vertical resolution |
The number of horizontal lines which can be resolved in a picture. It is limited by the television scanning method - NTSC, PAL etc. |
| Vertical shift register |
A part of the interline transfer CCD chip and is placed in between every column of pixels. At the end of each frame the charge from the pixels are sent to the vertical shift register (VSR) and then row by row to the horizontal shift register. |
| Vertical streaking |
type of picture distortion that occurs due to overloading of the pixels in an interline transfer chip. It appears as vertical streaks above and below the bright part of the picture. |
| Vext |
A multiplexer feature that uses a pulse generated by the VCR so that the multiplexer automatically adjusts to the VCR time lapse speed. |
| VHS Victor Home System |
A type of popular recording format used in video cassette recorders. The other type of formats are betamax, 8mm, system 2000 and U-matix (professional). |
| Vibration sensor |
A type of device which can be activated by vibrations in a pre determined zone and can be interfaced with a switcher to switch the nominated surveillance camera for extended viewing. |
| Video |
For films or movies, see Film. For other uses, see Video (disambiguation). For the use of video in Wikipedia articles, see Wikipedia:Creation and usage of media files. Video is the technology of electronicallycapturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion. |
| Video amplifier |
A type of amplifier used to boost the strength of a video signal. |
| Video cassette recorder |
A device which can record (or playback) video and audio signals on a magnetic tape housed in a cassette. |
| Video compression |
Video compression refers to reducing the quantity of data used to represent digital video images, and is a straightforward combination of image compression and motion compensation. Video compression is an example of the concept of Source coding in Information theory. This article deals with its applications: compressed video can effectively reduce the bandwidth required to transmit video via terrestrial broadcast, via cable TV, or via satellite TV services. |
| Video distribution amplifier |
A type of amplifier used not only to boost the strength but also create multiple outputs of the video signal. |
| Video file formats |
A container format is a computer file format that can contain various types of data, compressed by means of standardized audio/video codecs. Other flexible containers can hold many types of audio and video, as well as other media. The most popular multi-media containers are:
Example: . 3GP (used by many mobile phones)
.AVI (the standard Microsoft Windows container
.MPEG
.wma
H.264 |
| Video head |
An internal part of a VCR which rotates very rapidly and writes the video signal on to the video tape during recording while reading the video signal from the tape during playback. |
| Video intercom |
A door entry system which uses both audio and video to communicate and/or control movement of people. |
| Video monitoring |
A new trend which uses video to monitor remote sites in any part of the world. The video images are transmitted through the telephone network. |
| Video Motion Detection (V.M.D.) |
A system that uses the video signal from a camera to determine if there is any movement in the picture and set of an alarm. |
| Video motion detector |
device which can detect unwanted movement in the picture and then generate an alarm. |
| Video Printer |
A device that prints a hard copy image from a video signal. |
| Video Type Lens |
An auto-iris lens without an internal circuit to control the iris. All iris control voltages come from a circuit located within the camera. |
| Visible Light |
Wavelengths of light visible to the human eye. |
| Wave length |
The distance traveled by an electro magnetic wave during one cycle. |
| Wavelet |
A digital file commonly used in digital recording, which contains a representation of sound waves in digital form; limited in duration and frequency. |
| Weatherproof |
Adjective - able to withstand exposure to weather and adverse outdoor elements without deterioration |
| White Light |
The entire spectrum of visible light. |
| Wide angle lens (Fish Eye) |
A type of lens which gives a wide view of the scene and has a magnification ratio of less than 1. |
| Wireless |
Wireless communication is the transfer of information over a distance without the use of electrical conductors or "wires". The distances involved may be short (a few meters as in television remote control) or long (thousands or millions of kilometers for radio communications). When the context is clear, the term is often shortened to "wireless". Wireless communication is generally considered to be a branch of telecommunications. It encompasses various types of fixed, mobile, and portable two way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of wireless technology include GPS units, garage door openers and or garage doors, wireless computer mice, keyboards and headsets, satellite television and cordless telephones. |
| Y/C |
A method of sending video pictures in 2 separate parts down 2 separate cables. The component parts are Y (the Black and White portion) and C ( the color portion). |
| Zoom |
The ability to change the magnification of a scene. |
| Zoom lens |
A type of lens with a variable focal length ranging from wide angle to telephoto. |
| Zoom ratio |
The ratio between the maximum and minimum focal length of a zoom lens. |
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