A Glossary of visualizer related terms

a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z

A

Aliasing
Jagged edges along the outer edge of objects or text. Anti-aliasing refers to software adjustments that correct the effect which is created by inadequate sampling techniques in computer-produced images.
Active Pixel Sensor (APS)
Active Pixel Sensor, is an image sensor containing pixel sensors with a photo detector which connects to a transistor readout and reset circuit. CMOs and CCDs are typical types of image sensors.
Ambient Light
Is any light that is emitted in the presentation room that is created other than the display or projector.
ANSI
American National Standards Institute (ANSI Lumens)
Active Matrix LCD
Is a solid state device that controls each pixel in a display to deliver a high quality image.
Amp or Amplifier
Is a device that amplifies either a video or audio signal.
Aspect Ratio
Is the term used to describe the height and width of the frame of the screen. For example in a 4:3 aspect ratio the image is 4/3 times the height. The width is always the first number followed by the height.
Audio In
Input audio connection for an electronic device such as a VCR, usually female RCA jacks.
Audio Out
Output audio signal from a device such as a VCR or CD player, usually female RCA jacks.

B

Backlit
A device that is illuminated from behind like a remote.
Bandwidth
Measurement capabilities of data flow.
Barco N.V.
Barco is a display manufacuturer that specializes in CRT displays ranging from LCD and DLP projectors, LED displays, display walls and flat panel tvs. Barco originally stood for Belgian American Radio Corporation.
Baud Rate
Data transmission speed, 28.8K baud is 28,800 bits per second.
Bit Mapped Graphics
Is a graphics format that is defined on a bit-by-bit basis which makes all points on the screen display directly accessible.
BNC
This is the most common type of terminator that is used with coaxial cables receiving R, G, B, H-Sync information, and composite video.
Build Slide
"Build series " slides show audiences where a topic is heading a line at a time. Each new line added appears in a bright colour while previous the line drops back to a darker colour.

C

CCD
This device is also known as a Color-Capture Device. Charge-coupled device (CCD) is an image sensor, consisting of an integrated circuit containing an array of linked, or coupled, light-sensitive capacitors.
CMOS
Complementary metal-oxide-semiconductor (CMOS))is a class of integrated circuits. This technology is commonly found in chips such as microcontroller's microprocessors, static RAM, and other digital logic circuits. CMOS technology can also be used for analog circuits such as data converters, image sensors, and highly integrated transceivers.
Composite Video
This format of video is largely found for analog displays. The composite video is usually a yellow connector which is then couple by red and white audio. It is usually in standard format such as PAL, NTSC and SEECAM.
Compressed Resolution
This is a method used to reduce the resolution of a particular signal to allow it to operate on a lower resolution device. The image quality is reduced when the resolution is compressed.
Confidence Monitor
They are small monitors ranging from 3" to 6" in size. They are typically LCD monitors and their purpose to allow the presenter to view the image before it is displayed on a larger display device. The presenter will want to do this to make sure the appropriate subject is being viewed and is in focus.
Contact Image Sensors
CIS are a very recent technology innovation that are rapidly replacing CCDs in low power portable applications. A CIS typically consists of linear array of detectors, covered by a focusing lens and flanked by red, green, and blue LEDs for illumination. In general CIS devices produce a lower image quality to CCD devices.
Contrast Ratio
This is the ratio between black and white, the higher the contrast ratio the more ability the display device has to showing subtle color details and withstands ambient light. There are two methods used by the projection industry: Full On/Off contrast measures the ratio of light when the light output is all black (off) and all white (on). The second method is the ANSI contrast ratio that is measured with a pattern of 16 alternating black and white rectangles.
CRT
Cathode Ray Tube monitors (tube TVs) are seemingly old technology as they are being replaced by flat panel LCD and plasma screens.

D

DAT
Digital Audio Tape recorder/player
Decibel (db)
A measuring unit used to compare electronic signal levels of sound levels.
DIN

DIN Deutsches Institute fur Normung e.V. (DIN; in English, the German Institute for Standardization) is the German national organization for standardization and is that country's ISO member body.

DIN and mini-DIN connectors, as well as DIN rails are several examples of older DIN standards that are used around the world today. However, there are currently around thirty thousand DIN Standards, covering almost all fields of technology. One of the earliest, and surely the most well-known, is DIN 476, the standard that introduced the A4, etc. paper sizes in 1922. This was later adopted as international standard ISO 216 in 1975.

Desktop Videoconferencing
Videoconferencing via personal computer
DLP / Digital Light Processing

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.

In DLP projectors, the image is created by microscopically small mirrors laid out in a matrix on a semiconductor chip, known as a Digital Micromirror Device (DMD). Each mirror represents one pixel in the projected image. The number of mirrors corresponds to the resolution of the projected image. 800x600, 1024x768.

E

Epidiascope
The epidiascope is often referred to as the opaque projector, and is the predecessor to the overhead projector. It works by displaying opaque materials by emitting a bright light from above, then a series of prisms and mirrors are used to focus the image. In general epidiascopes require brighter bulbs and larger lenses than overhead projectors in order to project the reflected light.
Equalizer
Referred to simply as 'EQ', this is an audio device that contains multiple frequency controls for manipulating sound tone quality.

F

Focal Length
Focal length is the distance from the lens to the focal point. A wider viewing angle must be used for a small focal length.
Front Projection
This is a projection system that displays images by emitting light from the front of the screen onto the display surface. Front projection devices are typically DLP and LCD data projectors.

G

Genlock

This is the term used to describe the synchronization between two video sources. This is extremely necessary when trying to overlay computer graphics on an image from a camera, VCR or videodisc player.

Ghosting

Ghosting describes the shadow or weak secondary image that is sometimes displayed on a screen when there is a multiple path broadcast transmission errors.

Graphical User Interface

A graphical user interface (GUI) allows for interaction with a computer or other media formats, which employ graphical images, special graphical element devices called "widgets", along with text to represent the information and actions available to a user. The actions are usually performed through direct manipulation of the graphical elements

H

H Sync
H Sync is short for horizontal synchronization. It acts as a marker to show the computer or video signal it is the start of a line.
Hand Held Microphone
It is a microphone that can be held by hand or attached to a stand or lectern. They can come in two types; hard wired or wireless.
HDTV
High Definition Television
Hertz (Hz)
Hertz is a measurement unit for frequency. 1,000 Hz = 1,000 cycles per second.
High Gain Screen
Gain refers to the brightness of the picture on a screen, typically a white wall or a semi-matter screen. A high gain screen uses numerous methods to collect light and reflect it back to the viewers.
Horizontal Frequency
This is referred to as the sum of the total number of horizontal lines scanned per second on a display.
Horizontal Resolution
Horizontal resolution is the total number of vertical lines across the horizontal rows of a monitor.

I

IEEE
Institute of Electrical & Electronics Engineers, sets standards
Image Sensor
An image sensor is a device that converts a visual image to an electric signal. It is used chiefly in digital cameras and other imaging devices. It is usually an array of charge-coupled devices (CCD) or CMOS sensors such as active pixel sensors.
Infrared

Infrared, commonly referred to as IR is an electromagnetic radiation wavelength that is longer than visible light, but shorter than radio waves. Wavelengths range A liquid crystal display is a flat, thin display device that is made up of numerous monochrome or color pixels placed in front of a reflector or light source.

Interlaced

Is a method used to display pictures on display device. There are 2 horizontal video scans. They scan odd/even per video frame.

Interlacing

Is a method used to reduce flicker which is caused by the first created video field fades as the next video field is being written.

Inverted Image

Most projectors mounted on the ceiling are fixed upside down. The inverted image feature corrects the image so that the picture is not displayed upside down.

Interactive Whiteboard

Interactive whiteboards are increasingly being used in classrooms and boardrooms world wide as they are a great tool for displaying information and learning information. It is typically used as an interactive computer screen. A projected image is displayed on the screen and the presenter has the ability to annotate and control the computer via touching the whiteboard.

ISDN

Integrated Services Digital Network.

J

JPEG
Joint Photographic Experts Group see: www.jpeg.org/jpeg/index.html

K

Keystone
Keystone is a type of distortion called trapezoid distortion. It usually occurs when the projector is located lower than the screen center line or bottom. Most of the current projectors have a feature to control this.
Kilohertz (Khz)
Unit of frequency measurement. 1Khz = 1,000 cycles per second.

L

LCD Projection Panel
An LCD projection panel is a flat panel LCD device that can be placed on an overhead projector to display computer and video images.
Lenticular
Lenticular refers to a screen surface that has an embossed geometric shape pattern that is designed to affect reflection of ambient light and angle/view performance.
Light Valve Projector
Refers to projectors that are designed for theatre size screens. They are very bright and are capable of displaying images at a large level.
Lumen
The lumen (symbol: lm) is the SI unit of luminous flux, a measure of the perceived power of light. Luminous flux differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light
Luminance
Luminance is a photometric measure of the density of luminous intensity in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle.

M

Megahertz (Mhz)
Unit of frequency measurement. 1Mhz = 1,000,000 cycles per second.
Metal Halide Lamp
This type of lamp refers to the lamp used in most high-end portable projectors. They are capable of producing super white light with a hint of blue that even make halogen lamps look yellowish in comparison. The lamps output is extremely hot.
Mixer
A mixer is used for combining and adjusting multiple signals from various sources of audio and video.
Monitor
Commonly applied to Computer video display or CRT based TV.
Multimedia
Multimedia is media that combines numerous forms of information processing and information content (text, graphics, audio, video interactivity, graphics) to entertain or inform the audience.

N

Network
A network is commonly referred to as a computer network that connects two or more computers together enabling them to share information from one computer to the next.
A zoom lens with the controlled by a motor, usually adjusted from the control panel or remote control. This is as compared to Digital zoom, which does this same function digitally.

O

Overhead Projector
OHP are a type of projector that uses transparencies to display images to an audience.
Overlay
Overlay is a method that is used to superimpose text or computer generated graphics on still or motion video.

P

PAL
Phase Alternate Line. (Format used primarily in Western Europe.)
Parallel Port
An example of a device that uses this type of connection would be a printer that connects to the input/output port that transmits data at multiple bits at a time.
Pixel
Pixels are used to form an image on a display device. They represent one single point on a graphical image. Each point is not really considered a square or a dot but an abstract sample. When pixels are reproduced properly they can display an image without the appearance of visible squares or dots, however when they are reproduced without care the squares and dots can become visible as the pixels used to reproduce the image are not fine enough.
Plenums
They refer to enclosed spaces in buildings that are often used for heating, air conditioning, ventilation or any type of cabling. They are not meant for human occupancy. Plenum rated cable is found in these spaces as they are fire-resistnt and slow burning casing that allows them to be permitted under building regulations.
Poly-silicon LCD
This refers to the technology used in the top of the line LCD projectors. The result is increased color saturation, which has contrast ratios of 200:1 and above.
Power Zoom
A power zoom is a zoom lens that is controlled by a motor via the control panel on the unit or by a remote control. It is similar to a digital zoom that does the same function digitally.
Progressive Scan
This is a format that outputs data in a sequential order as it is scanned. This format produces a full frame video which is continuous rather than the interlaced which is displayed odd/even.

R

Radio Frequency
refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current which is fed to an antenna. A common use is to transport information through the atmosphere or outer space without wires. Radio waves are distinguished from other kinds of electromagnetic waves by their wavelength, a relatively long wavelength in the electromagnetic spectrum
RCA/Phono connector
An RCA jack, also referred to as a phono connector or CINCH/AV connector, is a type of electrical connector that is commonly used in the audio/video market. The name "RCA" derives from the Radio Corporation of America, which introduced the design by the early 1940s to allow phonograph players to be connected to amplifiers.
Rear Screen Projection
Rear screen projection is a display device that projects an image onto a translucent screen from behind.
Remote Mouse and Keyboard Control
Gives the presenter control of the computer presentation without having to have direct access to the projector or computer and allows for freedom of movement.
Resolution
Refers to the total number of pixels in the maximum screen viewing area. Common resolutions are 800 x 600. 1024 x 768 etc...
RGB
RGB stands for Red, Green, and Blue which are the basic light components that make up the image on the display device.
RS-232C
In telecommunications, RS-232 is a standard for serial binary data interconnection between a DTE (Data terminal equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports. A similar ITU-T standard is V.24.

S

Scan Rate
Scan rate is determined by the speed of the Horizontal and Vertical lines. They are usually specified in Kilohertz or Hertz.
Scanning
The electronic process of moving an electron beam across the CRT surface.
SECAM
Television standards, the TV system used in France and throughout the Eastern Block Republics.
Serial Port
Computer input/output connection that transmits data 1 bit at a time. (Ex. Mouse) Used for displaying 35mm and 2"x2" slides on a projection screen.
Slide View Box
Is a box that contains a light source and a translucent panel that is used to sort and view slides used by a slide projector.
Sync Synchronization
Sync synchronization is the process where scanning signals keep the video display generator locked to the appropriate source.
SVGA
Super Video Graphics Array. Resolution = 800x600 pixels
SXGA
Super Extended Graphics Array. Resolution = 1280x1024 pixels

T

Telephone Interface
Used to connect a sound system to a telephone line to allow for ease in large conference calls.
TFT-LCD
Thin Film Transistor-Liquid Crystal Display uses technology called Thin-Film Transistor technology to improve quality of the image. It is a type of active matrix liquid crystal display and is synonymous with LCD. This technology is used in both projectors and panel displays. TFT monitors are continually replacing the old CRT technology.
Throw Distance
Throw distance is the required length of the projection beam to display an image at a certain desired size.

U

UXGA
Ultra eXtended Graphics Array referring to a standard monitor resolution of 1600 x 1200 pixels, which is exactly quadruple the default resolution of SVGA (800 x 600).

V

Varifocal Lens
A varifocal lens is a lens that consists of 3 focal elements that are contained in a single assembly.
Vertical Resolution
Vertical resolution refers to the number of horizontal lines that can be seen in the vertical direction of the display.
VGA
Video Graphics Array. Resolution = 640x480 pixels
Video Conferencing

Video conferencing is a way of communicating with people who are a far distance away. The communicators are able to speak and hear the other person as well.

Video Compatibility
Video compatibility is the ability of display units, projectors and computers to receive data and play various video standards. (NTSC, PAL, SEECAM etc...)
Video In
Video in uses female RCA or BNC to connect an electronic device like a VCR or DVD player into the display device.
Video Out
Video out uses female RCA or BNC to pass the signal from a VCR or DVD player to a display device.
Video Switchers
Video switchers are used when there are several video sources going into one or more display devices that can be easily switched from one input to another.
V-Sync
Vertical synchronization. A marker in a video signal for the beginning of a frame.

W

Whiteboard (Interactive)
Interactive whiteboards are increasingly being used in classrooms and boardrooms world wide as they are a great tool for displaying information and learning information. It is typically used as an interactive computer screen. A projected image is displayed on the screen and the presenter has the ability to annotate and control the computer via touching the whiteboard.

X

XGA
Extended Graphics Array. Resolution = 1024x768 pixels

Y

Y/C Connector
Separate video, abbreviated S-Video and also known as Y/C (or erroneously, S-VHS and "super video") is an analog video signal that carries the video data as two separate signals (brightness and colour), unlike composite video which carries the entire set of signals in one signal line. S-Video, as most commonly implemented, carries high-bandwidth 480i or 576i resolution video, i.e. standard definition video. It does not carry audio on the same cable.
Y-Cable
A cable that splits the monitor signal so that it works simultaneously with both a monitor and another display device such as a confidence monitor.

Z

Zoom lens
A lens with a variable focal length, which provides the ability to adjust the size of the projected image on a screen by adjusting the zoom lens.