Projector Glossary of Terms

Projector Glossary

A

Aliasing

Aliasing is what you get when you print out written content and its edges are jagged. It may also apply to actual physical objects as well due to their poor finish. Anti-aliasing feature allows the projector to remove this problem. It is usually caused by inefficient sampling techniques in computer generated images.

Ambient Light

It is the light in the room from natural sources like daylight and artificial lighting as well. Basically it is every kind of light that is not being produced in the projector itself!

ANSI Lumens

ANSI is an acronym for American National Standards Institute and it designated a standard for measuring the light output for any projector. But, it may be deceiving to eye as it is more related to the intensity itself. Two sources with the same ANSI rating may appear different to the naked eye and vice versa. There are many factors that contribute to the overall rating of the projector in terms of ANSI lumens. The kind of LCD screen, contrast ratios, etc can affect the number of lumens.

Aperture

The opening that controls the light of the projector. It is usually associated with some of the older projectors.

Aspect Ratio

The ratio of height to width of any projector’s output is called the aspect ratio. If the aspect ratio is 4:3. It means that the width of the screen is 4/3 times more than the height. 4:3 is more common for current computers and TVs. The 16:9 is more common for movies for experiencing a theatre-like experience with a wider screen. HDTV is 16:9 is as well while the 35mm slides are 3:2.

Attenuate

Attenuate means to lower any output. You can attenuate the brightness by lowering it.

Anamorphic

This is a technique that is used to change aspect ratios from one to another. It is done digitally in modern projectors and the resulting projection may not work for you.

B

Backlit

A remote control, set of buttons or keyboard that is lit from underneath for better viewing in less light.

Bandwidth

Now bandwidth can mean a lot of things as it is a measure of the range of a particular transmission apparatus. You probably know about it in radio waves transmission and internet hosting but it is used in projector nomenclature as well. Here the bandwidth is expressed in MHz and the greater the quality of the video, the bigger the bandwidth will be required.

Balanced Input

It is a three input method in which two signal conductors propagate the signal while the third one is ground. This supposedly cancels any electromagnetic interference picked up enroute to the destination.

Bit Mapped Graphics

It is the display that is bit-by-bit assembled and defined and it makes all parts of your screen directly accessible to us.

Black Level

It is the darkest part of any given picture that you are trying to use the projector on. Now the darkest level is not right for many instances and it is rarely used, so what you see on the screen might be actually a deep shade of grey and not black.

BNC

This is a connector that is named after inventors Paul Neill & Carl Concelman. The connector receives composite video and a variety of R, G, B, H-Sync and V-Sync information that it puts to good use.

Build Slide

This feature allows the audience to keep track of the line the presenter are going through by indicating it with a different color than the rest of the lines.

Button

It is a graphical or sometimes physical switch in an interface or a machine that shows an inner function.

C

Calibrate

To adjust any instrument or device based on a standard unit or reference.

Color temperature

The temperature measuring method of any light source that shows how white it is. Different incandescent methods have varying color temperatures.

Clip-Art

Pictures, graphics and other visual aids that are already present in the library that can be imported into the presentation.

Coated Optics

It is a wide range of materials present on top of high quality lenses to reduce the light reflected back to the lamp to a minimum level. These coatings can save up to 15% light and add to the lenses brightness.

Color Resolution

The total number of colors available in any format, normally shown in bits per pixel.

Compatible

When different softwares and hardware can be used with each other directly without much alteration.

Contrast

It is a measure of the difference between white and black, two extremes of colors. If the difference is large, the contrast will be higher but we cannot make it too much because after a certain optimum point, it gets uncomfortable for the eye.

Contrast Ratio

The ratio between the black and the white is called the contrast ratio. The larger the ratio, the stronger the ability of the projector to provide well-detailed subtle colors and tolerate ambient light of the surroundings. So you will need to know a projector’s contrast ratio before making a decision but while comparing the specs, remember that contrast ratio in ON/OFF position and the ANSI contrast ratio assigned can be different from each other. So, always compare same contrast ratio values, either ANSI or full ON/OFF contrast.

D

dB

dB or decibels is a measure of loudness of any projector or sound source. 0-60 is normal loudness range while 120-140 dB is the range where pain starts to occur in our eardrums. Above 160 might kill you.

Diagonal Screen

It is the length of the screen from one corner to the diagonal corner. Now if you know a little bit about high school mathematics, the diagonal will always be longer than the height and width of the screen. A 9 ft long and 12 ft wide screen’s diagonal screen will be 15 ft. So keep that in mind.

Desktop Videoconferencing

Connecting with videolink on your personal computer.

Deinterlacer

This electronic part converts interlace video signal to a progressive scan for the projector.

Digital Light Processing

It is a light processing system first made by the Texas instruments where lots and lots of tiny spinning mirrors are used to reflect images in a projector. It is rated as a top way to reproduce color and images.

Dichroic

It is a lens or mirror that only allows selective wavelengths of light across it. It was used in old projectors to convert the parent white light of the projector into red, green and blue light.

Dithering

It is a digital way of making pictures appear smoother and better using added color and allowing random noise in.

E

Edge blending

It is a technique in which plural projectors are used side by side to project a wider image into one wide image on the screen.

Edge Enhancement

It is a method by which you can increase contrast around the object edges and thus increase object resolution.

EGA

It is also known as Enhanced Graphics Array and it is an option that displays 640 X 350 pixels with 16 colors from a possible 64.

F

Feedback

Feedback occurs when an output of a device returns back in some form to the same device as input. Signals like in projectors need to be amplified again and again and that uses some form of feedback in some instances.

Front Room Projector or Position

It is a unit or arrangement in which the distance to the screen maybe really small, as less as ¾ of the screen size itself or as much as 1.2 times the image size.

Flat Screen

It is a kind of CRT screen that is made as flat as possible by using more than a single electron gun to bombard electrons on it. It is now an obsolete technology I have to say.

FM

Yes, it is the same acronym like the radio and is called the frequency Modulation. So signal is transferred by altering the frequencies of a carrier signal’s wave.

Focal Length

This is the length between the lens and its focal point. If it the focal length is smaller, it means the lens is wide angle lens.

FPS

Frames Per Second of the video being projected. The frames need to be fast enough so that the naked eye and our brain cannot point out any delay.

G

Gamma

It is the relationship between the input video voltage and the output brightness.

Gauge

It is a measure of the thickness of the wire. The lower the gauge, the thicker the wire.

Genlock

It is the ability to sync the video signals between two different sources. It is necessary for overlaying a computer image to an image from another source like the camera.

Ghosting

It is a secondary image that is seen on the display or the screen due to bad image projection from the projector.

H

High Gain Screen

It is a kind of projecting screen that uses one or more methods to collect light and project it back to the viewers. It appears to increase the brightness of the projected image.

Hanging Dots

This is a problem in the projector where stationary dots exist between places where two colors meet. It is the caused by the interference of the primary video signal and the color signal.

HD TV

It is widescreen TV broadcasting that became popular after the advent of HD plasma televisions for the public.

HDMI

It is a port that is used to transfer video from laptop/PC to the projector via a cable. It allows us to project HD videos and resolutions.

Hz

Short form of Hertz. It is the number of frequency cycles per second. It may also be expressed in the form of superlatives like MHz.

I

Invert Image

You must have seen these projectors in class where a huge projector is mounted upside down from the ceiling. Invert image feature straightens the inverted image out for our viewing purposes.

IEEE

Institute of Electrical and Electronics engineering. It is an international society of electrical, electronics and computer engineers that makes standards and publishes research.

Interlacing

Projected images and videos tend to flicker a lot and interlacing is done to avoid this experience and make image transition smoother and quickers.

J

Jaggy

The sawtooth effect on lines that are neither horizontal nor vertical. It is also called aliasing sometimes and anti-aliasing techniques are used to counter this effect.

JPEG

It is an image file that is commonly found in your computer or smartphone. Short for Joint Photographic Experts Group.

K

Keystone Correction

It allows the projector to maintain a standard image projection on the screen that is rectangular in shape.

Keystoning

The problem of top or bottom lines to be pointing up or down. It is mitigated by keystone correction.

L

Latency

Latency is the lag between the giving of command and it carrying out that command. It is usually meant for LCD screens.

LCD

Liquid Crystal Display screens that generate high quality images using a matric of LCD elements rather than a Cathode ray. It was quite popular until recently when LEDs took over instead.

LED

Light Emitting Diode is a new kind of display technology that works even better than LCDs. It is the future of the projection technology.

Laser Pointer

A tiny laser powered pointer that is used by presenters to focus on any part of their presentation directly from their hands. It is used to direct the viewer’s attention over a particular part of the presentation only.

Lenticular

It is a screen that has an uneven geometric pattern that distorts the ambient light or the projection.

Long Throw Lens

It is a kind of projector lens that allows the image to be beamed from a long distance at the end of a room.

M

Memory card

It is a portable memory device that stores data for us to use on the go.

Metal Halide Lamp

This is the kind of lighting lamp used in many high-end projectors today. The output is a very hot, strong light that is in ways similar to light used in streetlights. These lights are usually super white and make halogen lamps, etc appear more yellowish than white.

Multimedia presentations

The integrated presentations that use sound, video, graphics and other components to relay the message.

N

Native resolution

The number of physical pixels available in any screen or display device. Different kinds of screens have different native resolutions that shows the maximum ability.

NTSC

The USA’s broadcast standard setting Committee short for National Television standards committee. It actually used lower resolution settings than most.

Network

It is a connectivity of different devices to transfer and share data.

O

Ohm

A measure of electric resistance.

Output

It is the data that a projector or any other device that can be converted and used to fulfill the device’s function.

Overlay

It is the ability to superimpose graphics on images and video.

Overhead Projector (OHP)

It is an old kind of projector that projects images from transparent slides.

P

PAL

Phase Altering Line is a broadcast standard that was developed in 1963. It is the standard color system used in Europe except France.

Pixel

It is short for picture element. It is the smallest part of the image in any resolution that is an independent element that can be manipulated in the data. The total number of pixels are normally shown in horizontal vs vertical configuration. E.g 640 x 480p.

Power Zoom

It is the ability of a lens to zoom in or out using an actual motor instead of just optically manipulating it. Digital zoom does the zoom digitally and the lens remains in its place.

Presentation Ergonomics

The study of relationship between a presenter, his audience and the whole presenting environment.

Projection Axis

The imaginary line of reference that is between the center of the projection to the center of the lens itself.

Q

Quicktime

It is a file format developed by Apple for video and other kinds of media. It is only suitable for apple devices.

R

Rainbow Effect

This effect only allows people viewing it from a certain angle to view the image correctly. This problem occurs due to the color breakup.

RGB

Red, Green and Blue. These are the colors normally associated with computers.

Real Time

If the rate of projection is so seamless that it appear to be happening in real time.

Rear Projection

This is the kind of projection done on cinema screens where a translucent screen is used for this purpose and video is projected from one side and seen on the other one. It is especially useful for large-scale audiences.

Resolution

It is the number of pixels per unit area of screen. It is normally shown in number of pixels in width to the number of pixels in height. More pixels mean the screen is high in resolution.

RS-232 C

It is a communication cable that connects computers with its peripherals.

S

Sampling Frequency

This is the speed at which the analog signal is duplicated in its representation. The higher the sampling frequency, the better the projector experience

Saturation

It is used to measure Color intensity. A highly saturated hue has an intense appearance.

Scan Rate

It is a different kind of representation of the speed of the display and normally given in kHz. A 15.75 kHz translates into 30 fps and thus smooth transmission.

Simulated Color

Sometimes the projected colors are not the same as original colors and thus they are stimulated. So, blue might appear green or green may indeed become purple on the screen than it was meant to be.

SVGA

It is short for Super VGA. It refers to a certain signal that is of higher resolution than a standard VGA signal and thus better. Up to 1600×1200 pixels can be displayed using SVGA.

T

TFT

Thin Film Transistor. It was used in the early generation LCDs for making active matrix displays.

Throw Distance

It is the length of the beam required to produce and project an image of a desited size on a projector.

U

Uniformity

It is a way of measuring the evenness of the display. A uniformity of 80% means that the difference between brightest and dimmest portions is 20%.

UXGA

It is the pixel density or resolution of any computer generation image. A UXGA projector is normally able to project 1600×1200 video mode on the screen.

V

VGA

Video Graphics Array. It is the standard analog graphics card that IBM used and became popular in the 90s.

VGA Resolution

It is an old resolution that had a 640×480 pixel density.

Varifocal Lens

It is a projector that has three focal parts in a single assembly

Vertical Banding

A problem in LCDs due to difference in manufacturing. I

V-Sync

Short for Vertical Synchronization. It shows the beginning of a video frame.

Vertical resolution

The pixels in the vertical direction.

Video Compatibility

Ability of projectors to receive video data from various video standards.

W

Widescreen

It is normal to call widescreen any aspect ratio that is bigger than 4:3. HDTV is widescreen at 16:9.

Whiteboard

It is a document conferencing capability in which a single document can be edited by different users simultaneously.

x

XGA

Short for Extended Graphics Adapter. It was adapted by IBM for VGA as well as other resolutions and supported 1024 x 768 pixels max.

Y

Y/C Connector

It is a 4-pin connector that is a separated Chrominance signal. It offers high resolutions.

Y-Cable

It is a cable that divides the monitor signal into two so one can be fed into the monitor while the other can be connected to any other screen like LED or LCD.

Z

Zoom Lens

It is a lens that has a variable focal length. So, the size of the image can be adjusted with the help of this zoom lens alone instead of having to move the projector backwards or forwards.