CCTV Glossary

AC refers to alternating current electricity. 220 Volts AC is the type of electricity commonly found in our homes though 110 V AC is the standard output voltage in some countries such as the U.S.A.

AC/DC refers to changing between alternating current (AC) and direct current (DC). CCTV cameras normally require a AC/DC power adaptor to convert the 220 Vac to 12 Vdc to operate.

Alarm/Event Operation is a feature found in many DVRs. This allows the user to interface alarm sensors (like a PIR motion detector) with the recording device through an alarm in/out port. The recorder can then be set to automatically start and stop recording when the alarm is triggered. However many DVRs can now activate recording using Video Motion Recording.

Amps (A) are used to measure electrical current consumption. 1 amp (A) = 1000 milliamps (mA). Typical AC/DC power adaptors for the CCTV cameras are rated 1A.

Analogue indicates a particular electrical signal which conveys electronic data (i.e. a video signal or audio signal). Information carried over an analogue signal is a representation of data by continuously varying quantities. An analogue electrical signal has a different value of volts or amperes for electrical representation of the original excitement (light, sound, etc.) within a dynamic range specific to the analogue device.

Antenna Element - Antennas for wireless equipment are constructed of elements which are specifically tuned to a given frequency or range of frequency to improve gain.

Antenna Gain refers to any increase or decrease in the strength of a wireless RF radio frequency signal when considering external antenna equipment. Gain is typically measured in terms of decibels (dB) or a number of times of magnification

Antenna Type refers to the design of a particular antenna. Common antenna types for wireless CCTV are dipole whip antenna (the most common), yagi, flat panel, omni-directional, parabolic dish, and heliophase.

Aperture of a lens on a video camera controls the amount of light which is allowed to reach the image sensor. Aperture is listed in terms of an F-stop number. As F-stop number increases (i.e. F/1.4, F/1.8, F/2.8), the amount of light permitted to reach the image sensor decreases.

Aspect Ratio is a specification for monitors. This term refers to the ratio between the width and height of a video image. Typically, CCTV cameras produce an aspect ratio of 4:3 (the vertical size of the picture is 75% of the horizontal width). This is the same ratio for compatibility with standard consumer televisions and video equipment as well as security-industry monitors and video recorders. Wide screen televisions, on the other hand, have a 16:9 aspect ratio

Audio indicates sound. When audio is listed as a feature of some video product, this usually means one of a few things: a device for monitoring sound (microphone), a wireless transmitter's ability to broadcast sound, or a video recorder's ability to record audio.

Automatic Light Control ( ALC ) indicates the image sensor's ability to automatically adjust in diverse lighting conditions to yield the most vivid video image possible.

Auto-Iris Lens is a lens with a built-in method of automatically controlling the lens aperture for the best video quality under diverse and changing lighting conditions. Auto-iris lenses can be especially helpful under very low light and bright direct forward light.

BNC is the type of connector plug commonly found on CCTV devices for video and audio input / output connections.

Back Lighting Compensation ( BLC ) indicates the image sensor's ability to automatically adjust in conditions where lighting is from behind the camera to deliver the sharpest and highest quality video image possible.

Bullet Camera - A bullet design refers to a camera with a cylindrical shape using an inline video imaging chip (rather than a board design). These cameras are sometimes also called "lipstick cameras" or "inline CCD cameras."

C/CS-Mount Lenses and Cameras - The security industry has agreed upon a standard size lens mounting thread and coupling diameter with C and CS mount lenses. Cameras built with this type of lens mount can easily be configured with any of a large variety of C and CS mount lenses available for CCTV. Although C and CS are not exactly the same size, most cameras designed for this type of lens can accept either configuration using a simple plastic adapter. These lenses are standardized and will always thread properly, but exchanging C and CS mount lenses does require back focusing. This process requires the user / installer to slowly find the exact right thread position of the lens to ensure a clear video image.

CCD stands for charged coupled device. This is a solid-state semiconductor element which uses hundreds of thousands of tiny pixel elements to accept light and translate that information into a vivid, visible picture image. A CCD is one type of camera image sensor. CCDs produce MUCH higher tvres, lower light sensitivity, and better overall video quality than CMOS images (also commonly found in CCTV industry cameras).

CCIR is the standard monochrome video format used in most of Europe , Israel , and some other places in the world. CCIR products are also generally referred to as PAL because all PAL products can also handle black and white CCIR video.

CCTV stands for closed circuit television: a video system which will only be monitored in a closed environment (as opposed to public broadcast).

CMOS stands for charged metal oxide semiconductor. This is one type of camera image sensor which uses a charged metal surface to detect light and create a video image.

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 refers to an internal computer component which processes analogue information (like a video or audio signal) into a digital format such as MJPEG, MPEG-4, Wavelet, etc. for electronic storage on digital recording media. Without a codec in place to compress and digitize video, digital video recording to a hard disk drive would not be possible.

Colour Camera - Cameras are available with either colour or monochrome image sensors. Colour cameras produce video images bearing the entire visible spectrum of colour. And because colour CCD cameras have come a long way in recent years, the colour of objects appear vivid, crisp, and distinguished on monitoring and playback of video.

Composite Video is the standard type of analogue video signal utilized by most CCTV video cameras. This signal is plug and play compatible with most consumer television.

Compression Method refers to the computer software technique the codec in a DVR video recorder (or DVR card) uses to convert the video signal to digital information so it can be compressed and stored on digital media like a hard disk drive. MPEG (M-JPEG) and Wavelet are the most common types of compressed digital video.

DC refers to direct current electricity. This is the type of electricity is used to power many small electronic devices. The majority of CCTV equipment are powered by 12 volts DC, which can easily be adapted from standard AC wall outlets using a regulated AC/DC transformer or obtained from a battery source.

Digital indicates information which is encoded into ones and zeros (binary code) by some computer processing element. Digital in this industry, however, can refer to several different things.

Digital Signal Processing (DSP) is a level of image correction or enhancement which takes place within a device using a digital computer element. This digital element encodes the information into digital information for the highest level of detail and quality.

Digital Video (DV) refers to video which has been compressed into digital information for storage onto digital storage media like a hard disk drive, CD, or DVD . The quality of digital video will vary depending on factors such as the camera quality and compression method.

Digital Video Recorder (DVR) - This device is capable of accepting one or more video (and sometimes audio) input signals for recording onto digital storage media. A DVR is basically a computer specifically designed to gather and compress video into a digital video format for storage on a hard disk drive or other form of digital media. DVRs are quickly replacing VCR video recorders for security and surveillance purposes without the need for changing tapes. Key differences between DVR and VCR recorders come to available features. Advanced DVRs are capable of accepting multiple video without the need for bulky and expensive multiplexers or video quads. As well, most DVRs offer built-in motion detection recording (without costly and conspicuous PIR motion sensors), and many can be remotely viewed and played back over the internet. Some models may easily be backed up onto external media for long term archival. These backup methods may include CDs, DVDs, flash media cards, or via USB to a computer or other storage device.

DVR Card - A DVR card is a device for installation in a home PC computer which converts that PC into a DVR digital video recorder by gathering video and compressing it into digital information onto a computer's hard disk drive. When all works well, this allows a home PC to record up to several surveillance cameras.

Electronic Shutter is the speed at which light is captured in fields of video by the CCD image sensor. Automatic electronic shutter determines the amount of light available and helps deliver the best quality video by dynamically adjusting for the current lighting conditions by toning down light levels in very bright situations and boosting brightness in low lighting situations.

Ethernet/Modem indicates a network communication device for computer-type devices. Most DVR video recorders come standard with built-in Ethernet LAN connection (with 'RJ-45' plug) to enable remote internet viewing and/or network operation.

Focal Length indicates the distance between the optical center of a lens and a video camera's image sensor device. For practical purposes, lens focal length refers to a camera's angle of view. Lenses with a higher focal length number have narrower, telephoto fields of view. A very low number focal length indicates a very wide field of view.

Field of View refers to the angle at which a camera is able to produce a visible image. This angle can be described in terms of diagonal, horizontal, or vertical degrees. A camera's field of view is determined by its lens configuration. Fixed lenses have set fields of view, while cameras with varifocal or power zoom lenses have adjustable fields of view.

Fixed Lens - A fixed focus lens has one set focal length with a specific field of view which cannot be changed. Any camera without a varifocal or power zoom has a fixed focus lens. This means that although the user cannot manipulate the field of view, everything in the picture beyond a few inches will be clear and in focus. Objects simply get smaller as they move further away from the camera.

Frame - a full frame of video is the combination of two image fields interlaced together. A frame is one basic screen capture taken by a camera. 30 frames are displayed in one second of real time video for NTSC format. PAL format is phased at a rate of 25 frames per second for real time.

Frames per Second (FPS) describes the number of full video frames displayed or recorded within one second. True real time video consists of 30 frames / sec for NTSC format and 25 frames / sec for PAL format.

FPS Display Rate indicates the number of frames per second a VCR or DVR recorder will display on a monitor for simultaneous viewing. The rate at which each camera is displayed is often NOT the same as the number of frames per second the recorder captures for playback.

FPS Record Rate describes exactly how many frames per second a video recorder can actually capture.

Gamma Correction refers to the correction of linear response of a video camera image sensor in order to compensate for the monitor phosphor screen nonlinear response. Without gamma correction set to the inverse (exact opposite corresponding value) of the monitor's gamma, a video camera would not be able to provide a complete video image for a unified display. Gamma correction is measured with the exponential value of the curve describing the non-linearity.

Hard Disk Drive ( HDD ) is a magnetic media storage device for recording digital information (like that used by computers or digital DVR video recorders).

HDD Capacity indicates the amount of information which can be stored on hard disk drive.

Image Sensor indicates the type of semiconductor which handles video processing inside of a camera. CMOS and CCD image sensors are the most widely available for security cameras in today's market. CCD cameras provide by far the highest quality video of any type of image sensor.

Lens - A lens is an optical device which bends light, focusing it on onto an image sensor to create a distinct, visible image. All video cameras (and still cameras) need lenses in order to obtain a clear picture. Lenses come in a variety of focal lengths. The focal length of a lens, in combination with the size of the imager, will determine its field of view.

Low Light (or low lux) Sensitivity refers to a camera's performance under low lighting conditions. The Sony 1/3 " Ex-View and SuperHAD CCD chip sets have the best low light performance.

Lux is a measure of light in terms of candle power (measured in foot candles). Lux is often given as a technical specification for cameras to describe the lowest level of light required for the camera to produce any kind of an image.

Manual Iris Lens is a lens with a built-in method of manually adjusting lens aperture for the best video quality for a specific lighting condition. Iris control on such a lens is set by hand to a particular fixed aperture, allowing for the best possible (often better than auto-iris lenses) brightness and contrast for a specific camera angle / shot.

Maximum Recording Time indicates the longest continuous duration of time which could be recorded onto storage media using a VCR or DVR video recorder. Maximum recording time for ALL recorders will depend on the user setting for time-lapse or real time recording and the amount of storage media capacity.

Monitor Screen Size indicates the actual physical size of a monitor's viewing screen. However, this measurement is often different than the actual part of the monitor which produces a picture. The monitor viewing size spec describes the size of the picture on a monitor.

Monitor Viewing Size indicates the size of a monitor's actual visible picture.

Multiplexer (mux) 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 real time 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 close up 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 .

NTSC is the standard colour video format used in North America , Japan , and some other places in the world.

Network Operation is a feature of many DVR digital video recorders. This allows the user to connect the DVR system to another computer or computer network for dynamic recording control and playback on other computers. Network operation is also interconnected with remote viewing capability for record and playback features over the internet. Connecting a DVR recorder to a PC network may require additional hardware such as a WAN or LAN router in addition to some prior networking knowledge and experience.

Operating Temperature indicates the temperature at which a device can safely and effectively works.

Output Voltage indicates the type of electrical current (AC or DC) and the voltage a device will emit to safely and effectively power another device.

PAL is the standard colour video format used in most of Europe , Asia , Israel , and many other places in the world.

PIR Motion Sensor refers to a motion detector with passive infrared technology. These alarm sensors are often used with alarm/event VCR and DVR video recorders to trigger recording upon the detection of physical movement. However, PIR motion sensors are bulky and expensive. As advanced video motion detection software continues to improve, motion detectors are quickly being replaced with the built-in features of high quality DVR recorders.

Pan refers to horizontal (side to side) dynamic motion of a camera. Any equipment capable of panning can rotate back and forth along a horizontal axis. Some equipment, indicated as " PTZ ," has the ability to pan as well as and zoom.

Pan/Tilt/Zoom ( PTZ ) indicates equipment 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.

Pinhole Camera indicates a video camera with a tiny pinhole lens built-in standard with the camera.

Pinhole Lens is only 1/16th of one inch in diameter, so cameras with tiny pinhole lenses can easily be hidden for covert video surveillance applications. Cameras with this type of standard lens are typically referred to as pinhole cameras.

Pixel - A camera's image sensor consists of thousands of tiny sensor elements known as pixels. These sensors detect information about light and colours and translate that information into a viewable video image through digital signal processing. Of the total pixels on a CCD imager, some are constantly dormant while others are effective and actively work to create an image.

Power Consumption refers to the amount of electrical current an electrical devices requires for operation, usually measured in amps (A) per hour (often seen in mA milliamps, 1 amp = 1000 milliamps). For example, a miniature video camera which draws 100 mA per hour will consume 1 ampere hour for every ten hours of continuous operation.

Power Zoom indicates the ability to adjust a camera's field of view by remote control. Power zoom may also be described as remote zoom.

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).

Quality Differences - There are literally hundreds of different cameras available in the CCTV industry which on the outside appear very similar. However, inside these cameras (the crucial part) are so many different image sensors, each with different levels of performance, that it becomes quite confusing to even the experienced camera shopper.

RCA is a common connector plug for standard consumer video and audio equipment. RCA jacks are found on all VCRs and televisions equipped to handle a composite video input. In most cases, RCA jacks are colour coded yellow, white, and red. BNC plugs are easily adapted to standard consumer RCA connectors using a simple one-piece plug adapter.

Real time (or real time) refers to video recorded at the same speed as action occurs (so it may be played back at the speed of real time without drag). Real time video is phased at 30 frames per second (60 fields per second) for NTSC video and 25 frames per second (50 fields per second) for PAL format equipment. Basically all VCR recorders record real time video, but MOST digital DVR recorders do not.

Recording Media refers to the magnetic storage device used to store recorded video. For many analogue recorders this is a tape cassette, but DVR recorders use HDD hard disk drives. CDs and DVDs can also be types of media used to record digital video.

Remote Control is a device used to control the features of a piece of equipment without physically adjusting anything on the equipment. Some products feature a wired remote control. This allows a user to control many functions remotely, but this controller must be plugged directly into the device. Other products can be used with a wireless remote control. These types of controllers allow the user to adjust functions remotely. The information is "beamed" wirelessly to the device using an IR infrared signal from the controller.

Remote Playback is a feature of many DVR video recorders. This allows users to play back recorded video over the internet from virtually any computer in the world.

Remote Viewing is a feature of many DVR video recorders. This allows users to monitor CCTV cameras over the internet from virtually any computer in the world.

Remote Zoom indicates the ability to adjust a camera's field of view by remote control. Remote zoom may also be described as powered zoom.

Resolution (TV lines) refers to the maximum number of vertical lines / pixel elements (horizontal tvres) a video camera is capable of displaying on a monitor or registering with a video recording device. Horizontal tvres indicates the number of pixel elements placed horizontally across each scanning line of tvres (vertical tvres). Horizontal tvres varies based on the abilities of each different camera and each different monitor. Although the number of TV lines of horizontal tvres is generally considered a measure of a camera's level of detail and sharpness, this specification does not always indicate true end video quality.

S/N (Signal-to-Noise) Ratio indicates the ratio of noise to actual total signal (in a video or audio signal generally speaking). 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).

Simplex, Duplex, and Triplex concern the operation of video recorders and multiple camera video processors like quads and multiplexers. Simplex, duplex, or triplex capability reveals the number of device capacities which 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 for a certain close up view. Triplex devices are capable of three tasks at the same time (usually record, playback, and zoom or other display functions).

Storage Temperature indicates the highest and lowest possible temperature at which a device can safely and effectively be stored or shipped.

Tilt refers to vertical motion of a camera. Any equipment capable of tilting can move up and down along a vertical axis. Some equipment, indicated as " PTZ ," has the ability to tilt as well as pan and zoom.

Time-lapse is a feature of most CCTV-industry VCR and DVR video recorders. Time-lapse refers to recording one still video image (frame) at fewer than 30 frames per second. The speed of this recording can usually be adjusted. Time-lapse video is therefore slower than real time recording and has a drag when the video is played back. One advantage of time-lapse recording is the ability to increase maximum recording time so longer periods of time can be captured on a video tape or digital hard disk drive media. However, a major disadvantage of time-lapse recording is missing many frames of video and missing much of what happens during a given period of time. There is no way to recover these missed frames on playback. For the ultimate in surveillance, real time video recorders deliver the most complete and accurate video information of what occurred.

Uninterruptible Power Supply ( UPS ) is a special type of power supply commonly found in the security industry. This power supply is used to back up the system for ten minutes or more in the event of a main power failure. The time duration of this available emergency power depends on the size of the UPS and the current power consumption of the equipment in use.

VCR stands for video cassette recorder. This is an analogue device capable of accepting a video (and usually audio) input signal for recording onto magnetic tape media. These tapes can then be played back using the same VCR .

Varifocal Lens allows the user / installer to manually adjust the camera's field of view. Varifocal lenses can therefore be changed to provide wider viewing angles or narrower telephoto viewing angles. Because of their adjustability, varifocal lenses are great when a camera will serve more than one purpose or to ensure proper focus without first determining an exact fixed lens focal length. Varifocal lenses are also typically referred to as zoom lenses.

Video Motion Detection is a feature of all DVR digital video recorders. This is an advanced software feature which can detect motion in a camera's field of view and begin recording based on this motion detection. This type of detection can in most cases be adjusted in sensitivity. As well, a user can select and deselect areas in each camera's view for motion detection function. Advanced video motion detection erases the need for bulky and expensive PIR motion sensors.

Video Quality is of course always subjective. However, when most users describe high quality video they are referring to a sharp and clear video image without distortion.

Weatherproof equipment has been specifically designed for safe use in most outdoor weather conditions. However, weatherproof equipment should not be considered waterproof because it is never intended for submersion under water.

White Balance Control (WBC) - This term refers an electronic process used to retain crisp, vivid colour saturation in the truest possible hues. The technology balances the image colours against a light colour object in the camera's view.

Zero Lux Operation refers to video imaging in pitch black (0.0 lux) lighting conditions. Monochrome CCD cameras can use IR Infrared lighting to yield crisp and distinguishable video images when absolutely no visible light is available.
 

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