Associated Hardware
Visualizers rely on other pieces of hardware to complete their purpose and are listed below. Other items of hardware can be enhanced by the addition of a visualizer and these are also discussed below:
- Control System
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The inclusion of RS-232 in a number of visualizers has now enabled room automation control systems to communicate with the visualizer and control it from within a fully integrated system such as Crestron or AMX. There a quite a number of automated room control products on the market now which are capable of controlling via RS-232 or infrared.
Back to the Top - CRT Projector / CRT Projection TV / Monitor
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A CRT projector is a video projector that uses a small, high-brightness CRT (or picture tube) as the image generating element. The image is then focused and enlarged onto a screen using a lens kept in front of the CRT face. Most modern CRT projectors are colour and have three separate CRTs (instead of a single, colour CRT), and their own lenses to achieve colour images. The red, green and blue portions of the incoming video signal are processed and sent to the respective CRTs whose images are focused by their lenses to achieve the overall picture on the screen.
Back to the Top - CRT Television / Monitor
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The cathode ray tube (CRT), invented by German physicist Karl Ferdinand Braun in 1897, is an evacuated glass envelope containing an electron gun (a source of electrons) and a fluorescent screen, usually with internal or external means to accelerate and deflect the electrons. When electrons strike the fluorescent screen, light is emitted.
Back to the Top - DLP Projector
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Digital Light Processing (DLP) is a technology used in projectors and video projectors. It was originally developed at Texas Instruments, in 1987 by Dr. Larry Hornbeck.
One application is DLP front projectors (small standalone projection units). DLP, along with LCD and LCoS are the current display technologies behind rear-projection television, having supplanted CRT projectors. These rear-projection technologies compete against LCD and Plasma flat panel displays in the HDTV market.
Back to the Top - Interactive Whiteboard
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Probably the most important item of hardware to be associated with the visualizer in recent years.
The visualizer is highly complimentary to the purpose of an Interactive Whiteboard and arguably is not complete unless used in conjunction.
visualizers enable the inclusion of live or saved images into the whiteboard presentation, making the combination exceptionally powerful.
An Interactive Whiteboard is device that interprets a projected two-dimensional surface that interacts with a computer's desktop. A typical use is as an electronic whiteboard but it is generally an interactive type of computer screen.
Interactive Whiteboards typically require a computer to generate the display via a projector. Typical software mimics the computer's mouse and keyboard. However, some models have basic whiteboarding functionality present within the physical whiteboard.
Back to the Top - LCD Display
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A liquid crystal display (commonly abbreviated LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very small amounts of electric power, and is therefore suitable for use in battery-powered electronic devices.
Back to the Top - LCD Projector
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An LCD projector is a type of video projector utilized for displaying video, images or computer data on a screen or other flat projection surface. It is the modern equivalent to the slide projector and Overhead Projector used in the past.
Back to the Top - LCOS Projector
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Liquid crystal on silicon (LCOS or LCoS) is a "micro-projection" or "micro-display" technology typically applied in projection televisions. It is a reflective technology similar to DLP projectors; however, it uses liquid crystals instead of individual mirrors. By way of comparison, LCD projectors use transmissive LCD chips, allowing light to pass through the liquid crystal. In LCoS, liquid crystals are applied directly to the surface of a silicon chip coated with an aluminized layer, with some type of passivation layer, which is highly reflective.
Back to the Top - Light Box Accessory
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As several models of visualizer are not equipped with their own light boxes, manufacturers will supply them as accessories. They are extremely useful for viewing transparencies and any other material which requires a backlight.
Back to the Top - Microscope
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visualizers provide audience viewing of images from a microscope with the aid of a microscope adaptor. As there are several common sizes of microscope eyepieces, manufacturers offer a range of adaptor sizes and some are included with the visualizer as standard.
Back to the Top - Plasma Display
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A plasma display panel (PDP) is a type of flat panel display now commonly used for large TV displays (typically above 32"). Many tiny cells located between two panels of glass hold an inert mixture of noble gases (neon and xenon). The gas in the cells is electrically turned into a plasma which then excites phosphors to emit light. It is often used in the home environment and is becoming increasingly popular in modern cultures.
Back to the Top - Projection Screen
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Often overlooked, the projection screen is a crucial part of any projection display and should be selected wisely. It is most unprofessional to display an image onto a blank wall. The characteristics of normal wall paint are not conducive to the correct display of images from a projector. Not using the correct screen is like putting cross-ply tyres on a Ferrari!
Back to the Top - Video Conferencing
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The core technology used in a videoconference (VC) system is the digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream is transmitted through a digital network (usually ISDN or IP).
The other components of a VC system include:
- Video input:
- video camera or webcam
- Video output:
- computer monitor, CRT television, Flat Screen or projector
- Audio input:
- microphones
- Audio output:
- usually loudspeakers associated with the display device or telephone
- Data transfer:
- analog or digital telephone network, LAN or Internet
There are basically two kinds of VC systems:
Dedicated systems have all the required components packaged into a single piece of equipment, usually a console with a high quality remote controlled video camera. These cameras can be controlled at a distance to pan left and right, tilt up and down, and zoom and have become known as PTZ cameras. The console contains all electrical interfaces, the control computer, and the software or hardware-based codec.
Omni directional microphones are connected to the console, as well as a display with loudspeakers and/ or a video projector. There are several types of dedicated VC devices:
Large group VC are non-portable, large, more expensive devices used for large rooms and auditoria.
Small group VC are non-portable or portable, smaller, less expensive devices used for small meeting rooms.
Individual VC are usually portable devices, meant for single users, have fixed cameras, microphones and loudspeakers integrated into the console.
Desktop systems are add-ons (hardware boards, usually) to normal PC's, transforming them into VC devices. A range of different cameras and microphones can be used with the board, which contains the necessary codec and transmission interfaces. Most of the desktops systems work with the H.323 standard. Video conferences carried out via dispersed PCs are also known as e-meetings.
For example, see www.lifesize.com.
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