- the opening of the cctv lens. the size of which is controlled by the iris and is measured in f numbers. generally, the lower the f number, the larger the aperture is and consequently more light ...
|dvr (digital video recorder)|
A digital video recorder is a generic term for a device that is similar to a vcr but records television data in digital on a hard drive as opposed to a vcr tape. a dvr looks like a vcr and has all...
|osd (on screen display)|
- A method of displaying set-up information and/or instructions on a display monitor.
- Информация наложенная на изображение на экране, например дата, время, меню и т.д.
A quality brand of dvr cards made for windows based computers. a complete line of geovision dvr cards can be seen here: geovision dvr cards.
A type of cable typically used in cctv installations that has a central conductor, surrounded by a shield sharing the same axis. the shield can be made from a variety of materials including, braid...
|wdr security cameras|
A wdr security camera (wide dynamic range) is used for capturing clear images of objects surrounded by a strong back light, while still keeping the background visible.
- Bnc is a connector for coaxial cable that is most commonly used for cctv installations.
- Разъем bnc
|ccd charge coupled device|
Charge coupled device, ccd, is one of the two main types of image sensors used in security cameras. when a video is recorded, the ccd is struck by light coming through the camera`s lens. each of t...
|ip waterproof rating|
Ip waterproof ratings are a bsi standard measurement for how waterproof something is. many security cameras or camera housings are designed for outdoor use need to be waterproof. the ip rating num...
Security cameras with auto iris, have the ability to compensate for large variations in light levels. this is useful for security cameras that need to adjust for changes from bright sunlight to da...
|lcd (liquid crystal display)|
- Technology used for flat screen displays.
- Lcd screens, usually found on the rear of digital cameras, allow you to preview and review photographs you are about to take or have taken....
|dwell time programming|
The length of time a switcher or cctv multiplexer displays one camera before sequencing to the next. multiplexers with dwell time programming capability allow you control this length of time.
|c mount lens & cs mount lens|
There are two main types of lenses used in security cameras. the c mount lens has a flange back distance of 17.5mm. the cs mount lens has a flange back distance of 12.5mm. c mount lenses therefore...
|back light compensation|
This is a feature of security cameras that automatically adjusts the image to compensate for bright light to give more detail on the darker areas of the image. for example, use is to focus on the ...
|television lines (tvl)|
This is a measure of the resolution of a video device. the higher the number, the higher the resolution is. 380 tvl is considered medium resolution. 480 tvl or greater is considered high resolutio...
|signal to noise ratio (s/n ratio)|
This is the ratio between the signal strength and the noise levels on an audio or video signal.
This refers to a camera that is designed to record pictures and transmit them directly over a computer network or internet connection. network cameras normally do not have any analogue video outpu...
This refers to a type of lens that has the capability to change the focal length. this allows adjustment of the magnification and field of view of the security camera.
|auto light range|
The range of light, e.g., sunlight to moonlight, over which a tv camera is capable of automatically operating at specified output.
An arrangement whereby the frequency of an oscillator is automatically maintained within specified limits. afc;
|automatic iris lens|
A lens that automatically adjusts the amount of light reaching the imager.
señal de vídeo .;
- That portion of the composite picture signal which lies between the trailing edge of the horizontal sync pulse and the trailing edge of the corresponding blanking pulse.
- 1. the port...
|bar test pattern|
Special test pattern for adjusting color tv receivers or color encoders. the upper portion consists of vertical bars of saturated colors and white. the power horizontal bars have black and white a...
bloom, 4. blow 1.; выпотевание; вуаль; дефект из-за переэкспонирования светлых участков при сканировании;; просветление;
- The defocusing of regions of the picture where the brightness is at an excessive level, due to enlargement of spot size and halation of the fluorescent screen of the cathode-ray picture tube. ...
Also called burn. an image which persists in a fixed position in the output signal of a camera tube after the camera has been turned to a different scene or, on a monitor screen.
A television camera lens mount of the 16 mm format, 1 inch in diameter with 32 threads per inch.
- A control of color television receiver that regulates the saturation (vividness) of colors in a color picture.
- Регулятор цветности
Detects the absence of chrominance information in a color encoder input. the chroma detector automatically deletes the color burst from the color encoder output when the absence of chrominance is ...
cromaticidad; cromatismo; хроматичность; цветность качественная характеристика цвета;
- The color quality of light which is defined by the wavelength (hue) and saturation. chromaticity defines all the qualities of color except its brightness.
- The color quality of light...
- The process that established a fixed level for the picture level at the beginning of each scanning line.
- Applying a cross-head, or stirrup-piece, in a socket. фиксация; зажим;; зажатия; фиксирование; ставляющей; зажим; закрепление;; ограничение; фиксирование;; схема восстановления постоянной составляющей;
- That portion of the composite color signal, comprising a few cycles of a sine wave of chrominance sub carrier frequency, which is used to establish a reference for demodulating the chrominance...
Extraneous colors appearing at the edges of colored objects, and differing from the true colors in the object.
A device which produces an ntsc color signal from separate r, g, and b video inputs.
Spurious colors introduced into the picture by the change in position of the televised object from field to field.
The degree to which a color is free of white or any other color. in reference to the operation of a tri-color picture tube it refers to the production of pure red, green or blue illumination of th...
- The degree to which a color is free of white light.
- Насыщенность цвета
|color sync signal|
A signal used to establish and to maintain the same color relationships that are transmitted.
- The transmission of a signal which represents both the brightness values and the color values in a picture.
- A method of transmitting color television signals which can reproduce the...
|composite video signal|
- The combined picture signal, including vertical and horizontal blanking and synchronizing signals.
- A signal in which the luminance and chrominance information has been
- A ...
The ratio between the whitest and blackest portions of television image.
|depth of focus|
profundidad de foco .; глубина резкости объектива;
- The range of sensor-to-lens distance for which the image formed by the lens is clearly focused.
- The distance over which the focused laser spot has a constant diameter and thus const...
The signal used for the synchronizing of scanning specified in eia standards rs-170, rs-330, rs-343, or subsequent issues.
Also called f number and f system. refers to the speed or ability of a lens to pass light. it is calculated by dividing the focal length of the lens by its diameter.
See lumen/ft 2.
|foot lambert (fl)|
A unit of luminance equal to 1/candela per square foot or to the uniform luminance at a perfectly diffusing surface emitting or reflecting light at the rate of one lumen per square foot. a lumen p...
The number of times per second that the frame is scanned. the u.s. standard is 30 frames per second.
The method by which color and black and white sideband signals are interwoven within the same channel bandwidth.
fr; частотная характеристика; respuesta en frecuencia .;
- The range of band of frequencies to which a unit of electronic equipment will offer essentially the same characteristics.
- Частотная характеристика
- The portion of a composite picture signal which lies between the leading edge of the horizontal blanking pulse and the leading edge of the corresponding sync pulse.
- The blanking sig...
- A device used to lock the frequency of an internal sync generator to an external source.
- Circuitry that synchronizes one video signal to another video signal. there are three types ...
|impedance (input or output)|
- The input or output characteristic of a system component that determines the type of transmission cable to be used. the cable used must have the same characteristic impedance as the component....
- The light that falls directly on an object.
- A ray of light that falls on the surface of a lens or any other object. the "angle of incidence" is the angle made by the ray w...
- A scanning process for reducing image flicker in which the distance from center to center of successively scanned lines is two or more times the nominal line width, and in which the adjacent l...
An amplifier with input circuitry and output circuitry designed to eliminate the effects of changes made at either upon the other.
|lens preset positioning|
Follower pots are installed on lens that allows feedback to the controller information relevant to zoom and focus positioning allowing the controller to quickly adjust to a pre-selected scene and ...
Also called looping. the method of feeding a series of high impedance circuits (such as multiple monitor/displays in parallel) from a pulse or video source with a coax transmission line in such a ...
Distortion effects which occur at low frequencies. in television, generally considered as any frequency below the 15.75-khz line frequency.
The unit of luminous flux. it is equal to the flux through a unit solid angle (steradian) from a uniform point source of one candela or to the flux on a unit surface of which all points are at a u... unidad de flujo luminoso .;
A unit of incident light. it is the illumination on a surface one square foot in area on which a flux of one lumen is uniformly distributed, or the illumination at a surface all points of which ar...
- That portion of the ntsc color television signal which contains the luminance or brightness information.
- That portion of the television signal which conveys the luminance or brightn...
In monochrome television, a signal wave for controlling the brightness values in the picture. in color television, that part of the signal wave which has major control of the brightness values of ...
The transmission of a signal wave which represents the brightness values in the picture, but not the color (chrominance) values.
- A filter that attenuates light evenly over the visible light spectrum. it reduces the light entering a lens, thus forcing the iris to open to its maximum.
- Stands for neutral density...
A video signal containing all information except sync.
|pan and tilt|
A device upon which a camera can be mounted that allows movement in both the azimuth (pan) and in the vertical plane (tilt).
|pan/tilt preset positioning|
Follower pots are installed on pan/tilt unit to allow feedback to the controller and provides information relevant to horizontal and vertical positioning, allowing the controller to quickly adjust...
|peak pulse amplitude|
The maximum absolute peak value of a pulse, excluding those portions considered to be unwanted, such as spikes.
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 dist...
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 ...
The details that can be distinguished on the television screen. vertical resolution refers to the number of horizontal black and white lines that can be resolved in the picture height. horizontal ...
Also called image burn. a change produced in or on the target which remains for a large number of frames after the removal of a previously stationary light image and which yields a spurious electr...
|rf (radio frequency)|
A frequency at which coherent electromagnetic radiation of energy is useful for communication purposes. also, the entire range of such frequencies.
scan; сканирование; сканирования; развертки;
- The process of moving the electron beam of a pickup tube or a picture tube across the target or screen area of a tube.
- The process of breaking down an image ...
|standard minimum signal|
1000 micro-volts at 75 ohms (0db mv) in rf systems; 0.7-vpp non-composite, 1-vpp composite in video systems.
synchronization; synchronizer control;
- A contraction of "synchronous" or "synchronize".
- Synchronizer control
A device for generating a synchronizing signal.
The level of the peaks of the synchronizing signal.