3:2 Pulldown Recognition or 3:2 Inverse Telecine
Film is usually recorded at 24 frames per second. NTSC video is 30 frames (60 fields) per second. In order to get smooth motion, the film frames are broken into video fields in a 3-2-3 sequence. 3 fields for the first film frame, 2 fields for the second film frame, and so on. If a line doubler doesn't compensate for the extra field during playback on a progressive-scan display, the image will have noticeable motion artifacts. A line doubler with 3:2 pulldown recognition or 3:2 inverse telecine can see this sequence in the signal and correct for it by making sure the last field in the first frame isn't mixed with the first field of the second frame.

A/D
Analogue to Digital.

Anamorphic
Process that horizontally condenses (squeezes) a 16:9 image into a 4:3 space, preserving 25 percent more vertical resolution than letterboxing into the 4:3 space. For the signal to appear with correct geometry, the display must either horizontally expand or vertically squish the image. Also called Enhanced for Widescreen or Enhanced for 16:9.

ANSI Lumens
Is a measurement of the overall brightness of a projector. The center of a projected image is brighter than the corners. ANSI lumens is a the most accurate representation of the image brightness. ANSI lumens are calculated by dividing a square meter image into 9 equal rectangles, measuring the lux (or brightness) reading at the center of each rectangle, and averaging these nine points.

ANSI
Acronym for American National Standards Institute; coordinates the development of U.S. voluntary standards in the public and private sectors. ANSI has established the standard followed by projector manufacturers for measuring lumen brightness.

Aspect Ratio
The ratio of image width to image height. A 16:9 (HDTV) aspect ratio will produce an image that is 16 units wide for every 9 units high. This is also referred to as ˜ 1.78:1 meaning the width is ˜ 1.78 times the height. Common motion-picture ratios are 1.85:1 and 2.35:1.Other common aspect ratios are 3:2, 4:3 and 5:4. Native aspect ratio refers to the aspect ratio of the physical displays built into the projector. For example, a 1280 x 720 pixel display has a 16:9 native aspect ratio. A display that is 640 x 360 pixels is also a 16:9 aspect ratio, but with a fourth of the resolution of the other display. When widescreen movies (films with aspect ratios wider than 1.33:1) are displayed on wider than 1.33:1 screens, the image must be letterboxed, anamorphically squeezed, or panned-and-scanned to fit the screen.

Black Level
Light level of the darker portions of a video image. A black level control sets the light level of the darkest portion of the video signal to match that of the display's black level capability. Black is, of course, the absence of light.

Brightness
For video, the overall light level of the entire image. A brightness control makes an image brighter; however, when it is combined with a contrast, or white level control, the brightness control is best used to define the black level of the image. (Brightness is pretty much the same as Luminance).

Chroma:
The characteristics of color information, independent of luminance and intensity. Hue and Saturation are qualities of chroma. Black, grey and white objects do not have chroma characteristics.

Color Dynamics
The whitest whites, greenest green, etc. High color dynamics are a result of dynamic range/contrast ratios. A unit described as having excellent color dynamics often means it has rich colors, excellent definition, high contrast... Component Video
Component Video is a method of delivering quality video (RGB) in a format that contains all the components of the original image in its separate components. Typically refers to Y/Pb/Pr (analog) or Y’Cb’Cr (digital), which consists of three 75-ohm channels: one for luminance information, and two for color (chrominance).

Composite Sync
A signal of horizontal sync pulses, vertical sync pulses and equalizing pulses only, with no signal reference level.

Composite Video
A signal that contains both chrominance(Red, Green and Blue (RGB)) and luminance on the same signal cable(usually a BNC or RCA type of connection). Used in nearly all consumer video devices. Chrominance is carried in a 3.58-mHz sideband and filtered out in the receiving image devise. Poor filtering can result in dot crawl, hanging dots, or other image artifacts.

Contrast
Relative difference between the brightest and darkest parts of an image. A contrast control adjusts the peak white level of a display device.

Contrast Ratio
The ratio between white and black. There are two methods to measure: 1) Full On/Off contrast measures the ratio of the light output of an all white image (full on) and the light output of an all black (full off) image. 2) ANSI contrast is measured with a pattern of 16 alternating black and white rectangles. The average light output from the white rectangles is divided by the average light output of the black rectangles to determine the ANSI contrast ratio.

Chrominance
(C) The color portion of a video signal.

CRT
Cathode Ray Tube - A vacuum tube that produces light when energised by the electron beam generated inside the tube. A CRT has a heater element, cathode, and grids in the neck of the tube, making up the "gun". An electron beam is produced by the gun and is accelerated toward the front of the display, or screen surface of the tube. The display contains phosphors that light up when hit by the electron beam.

D/A
Digital to Analog

Decibel (dB)
A logarithmic measurement unit that describes a sound's relative loudness. A decibel is one tenth of a Bel. In sound, decibels generally measure a scale from 0 (the threshold of hearing) to 120-140 dB (the threshold of pain). A 3dB difference equates to a doubling of sound pressure level.

DMD
Digital Micromirror Device. Texas Instruments engine that powers DLP projectors. Uses an array with tens of thousands of microscopic mirrors that reflect a light source toward or away from the lens, creating an image. Each mirror represents a pixel. See video on Texas Instruments web site >>

DLP
Digital Light Processing, a data projection technology developed by Texas Instruments using a microprocessor to display bright, colorful images. The DLP chip contains millions of microscopic mirrors fabricated with 'hinges' on a static ram access chip (DMD), one for each pixel - that flip on an axis, reflecting light through a color wheel to create an image. The mirrors are capable of switching the pixel on and off more than 1000 times per second. An average human hair is as wide as the width of four mirrors. See video on Texas Instruments web site >>

DTV
DTV refers to the three types of digital television including Standard Definition Television (SDTV), Enhanced Definition TV (EDTV), High Definition Television (HDTV).

DVI
Digital Visual Interface. DVI is a connection standard that defines the digital interface between digital devices. For devices that support DVI, a digital to digital connection can be made that eliminates the conversion to analog and thereby delivers an uncompressed digital signal to the display. The latter version uses HDCP copy protection to prevent unauthorized copying. See also HDMI.

EDTV
Enhanced/Extended definition television is a class of digital television (DTV) that refers to the 480p format. 480p is a progressive scan video format that produces a full frame of 480 lines of video. Defined as those products that can display DTV images as 480p or higher.

Focal Length
The distance from the surface of a lens to its focal point.

Focus
A point at which rays of light converge. It is adjusted to clarify a blurry image.

Gray Scale
The ability for a video display to reproduce a neutral image color with a given input at various levels of intensity.

Gain
Is a measurement of the reflectivity of any screen or projection surface. The gain number represents a ratio of the light that is reflected from the screen (as compared to the light reflected from a standard white board). A screen with a gain of 1.0 will reflect the same amount of light as that from a white board. A screen rated at 1.5 gain will reflect 50% more light as that from a white board, whereas a gray screen with an 0.8 rating will reflect 80% of the light from a white board.

Genlock
A method of synchronising video equipment by using a common external "Genlock" signal.

HDCP
High-Bandwidth Digital Content Protection. Created by Intel, HDCP is used with HDTV signals over DVI and HDMI connections and on D-Theater D-VHS recordings to prevent unauthorized duplication of copywritten material.

HDMI
High Definition Multimedia Interface (connection format using a DVI interface ) is an uncompressed, all-digital audio/video interface that supports audio/video sources such as a set-top box, DVD player, A/V receiver, and video monitors such as a digital projector or digital television (DTV). HDMI is backward compatiable with DVI 1.0 specification and supports HDCP. HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio, and interactive controls on a single cable. It transmits all ATSC (Advanced Television Systems Committe) HDTV standards and supports 8-channel digital audio.

HDTV
High-Definition Television. The high-resolution subset of our DTV system. The FCC has no official definition for HDTV. The ATSC defines HDTV as a 16:9 image with twice the horizontal and vertical resolution of our existing system, accompanied by 5.1 channels of Dolby Digital audio. The CEA defines HDTV as an image with 720 progressive or 1080 interlaced active (top to bottom) scan lines. 1280:720p and 1920:1080i are typically accepted as high-definition scan rates.

Interlaced Video
Video systems in which each frame of video consists of two video fields. The odd numbered lines are contained in the first field and the even numbered lines are contained in the second field. When the image is delivered to a video device, the odd and even fields are delivered at 50 or 60 fields per second and your eye sees an integrated image. A 1080i HD signal transmits and displays only 540 lines per 60th of a second. 480i NTSC transmits and displays only 240 lines per 60th of a second. Interlaced images have motion artifacts when two fields don't match to create the complete frame, often most noticeable in film-based material.

Keystone
Horizontal & vertical stretching of a projected image. Used when a projector is not perpendicular to the screen, thereby creating an image that is not rectangular.

Keystone Correction
Keystone correction makes a projected image rectangular. This can be accomplished by positioning the projector to be perpendicular to the screen. Since this is not always possible, most projectors are equipped with keystone correction that allows the image to be keystone corrected (made rectangular) by adjusting optics, making mechanical adjustments, or applying digital correction to the image. Keystone correction can be one or two dimensional and manual or automatic depending on the projector and the manufacturer.

LCD
Liquid Crystal Display. A display that consists of two polarizing transparent panels and a liquid crystal surface sandwiched in between. Voltage is applied to certain areas, causing the crystal to turn dark. A light source behind the panel transmits through transparent crystals and is mostly blocked by dark crystals.

LCOS
Liquid Chrystal on Silicon

Letterbox
A method of preserving the originally aspect ratio of a production when presented on a projector with a different aspect ratio. Used on many DVDs to fit wide-aspect-ratio movies (1.85:1 and 2.35:1, for example) into a smaller frame, such as the 1.78:1 area of an anamorphic DVD. The image is shrunk to fit the screen, leaving blank space on the top and bottom. This process sacrifices some vertical details.

Luminance
The black and white (Y) portion of a composite, Y/C, or Y/Pb/Pr video signal. The luminance channel carries the detail of a video signal. The color channel is laid on top of the luminance signal when creating a picture. Luminance is any value between black and white.

Lux
A standard for measuring light, The amount of light per square meter, incident on a surface. 1 lux = 1 lumen/square meter = 0.093 footcandles.

Monochrome Signal
A "signal colour" video signal - usually a black and white signal, or sometimes the luminance portion of a composite or component colour signal

Native Resolution
Refers to the number of physical pixels in a display device. For example, an SXGA+ projector has 1400 physical pixels of resolution horizontally and 1050 pixels vertically or 1.470.000 total pixels. This is the native resolution of the projector. Projectors are capable of projecting greater or smaller resolution images into the same physical resolution through scaling. Scaling reduces the resolution of larger images and increases the resolution of smaller images to match the native resolution of the display device. This type of digital scaling always produces some artifacts in the image that are more apparent when viewing text than graphics or video.

NTSC
National Television Standards Committee (U.S. color TV standard from 1953) The United States standard for video and broadcasting. In NTSC, 30 frames are transmitted each second. Each frame is made up of 525 individual scan lines. (Also known, sarcastically, as Never Twice the Same Color due to the inherent difficulty in achieving proper color calibration)

PAL
Phase Alternating Lines. A European and international broadcast standard for video and broadcasting. 25 frames are transmitted each second. Each frame is made up of 625 individual scan lines. Higher resolution than NTSC

PGA
Professional Graphics Adapter. Resolution 640 x 400.

Pixel
Short for picture element. The smallest graphic unit of an image.

Plasma
Flat-panel display technology that ignites small pockets of gas to light phosphors.

Primary Colours
Colours, usually three (RGB), which are combined to produce the full range of other colours within the limits of a system. All non-primary colours are mixtures of two or more of the primary colours.

Progressive Scan
A type of display in which all the horizontal lines of an image are displayed at one time in a single frame, unlike an interlaced scan in which a frame consists of two separate fields with the first field consisting of odd horizontal lines and the second field even horizontal lines. Also called Non Interlaced

QVGA
1280x960 (4:3 ratio) Giving a total display resolution of 1.228.800 individual pixels.

QXGA
2048x1536 (4:3 ratio) Giving a total display resolution of 3.145.728 individual pixels.

QSXGA
2560x2048 (5:4 ratio) Giving a total display resolution of 5.242.880 individual pixels.

QSXGA+
2800x2100 (4:3 ratio) Giving a total display resolution of 5.880.000 individual pixels.

QUXGA
3200x2400 (4:3 ratio) Giving a total display resolution of 7.680.000 individual pixels.

Rear-Projection
Display that projects an image on the backside of a screen material, usually after having been reflected off of a mirror. (related terms are Rear Projection Television or RPTV).

Resolution
Means the number of pixels contained in the maximum screen viewing area. Usually reffered to as horizontal by vertical like: 1400x1050, 1920x1080 …. The more pixels your screen displays, the more stuff you can cram onscreen and as you pack more pixels into the same area, all those pixels get smaller...

RGB
Red, Green, Blue. Can refer to an unprocessed video signal or the color points of a display device. Together these three colors make up every color seen on a display device.

RS232
An Electronic Industries Association (EIA) serial digit interface standard specifying the electrical and mechanical characteristics of the communication path between two devices. This standard is used for relatively short range communications and does not specify balanced control lines.

Saturation
The intensity of the colour is called saturation. For example, a lightly saturated red looks pink. On a display device, it can be adjusted with the colour control. Not to be confused with the brightness, saturation is the amount of pigment in a colour, and not the intensity. Low saturation is like adding white to the colour.

Scan-Doubling
The process of eliminating the visible video scan lines by doubling them and filling in the blank lines.

Scan Rate
Horizontal and Vertical scan speeds, usually specified in Kilohertz or Hertz.

SDI
Serial Digital Interface. A digitized video interface used for broadcast grade video.

SDTV
Standard Definition Television. Lower resolution subset of the ATSC's DTV system. 480i is typically accepted as an SD signal. 480i is an interlaced video format that produces a full frame of 480 lines of video in two successive fields. The first field includes the odd lines and the second field includes the even lines.

SECAM
Sequential Color Avec Memoire. Primarily used in France, Eastern Block and Middle Eastern Countries. Higher resolution than NTSC.

S-Video
A video transmission standard that uses a 4 pin mini-DIN connector to send video information on two signal wires called luminance(brightness, Y) and chrominance(color, C).The two other pins cary grounding. S-Video is also refered to as Y/C. A composite signal, typically found coming out of an RCA jack on the back of most VCRs has the Y and C information combined into one signal. The advantage of having luminance and chrominance separated is that a comb filter is not needed in order to separate the composite signal into the luminance and chrominance signals. A comb-filter can reduce the sharpness of your video image.

SVGA
800x600 (Super Video Graphics Array) (4:3 ratio) Giving a total display resolution of 480.000 individual pixels.

SXGA
1280x1024 (Super Extended Graphics Array) (5:4 ratio) Giving a total display resolution of 1.310.720 individual pixels.

SXGA+
1400x1050 (4:3 ratio) Giving a total display resolution of 1.470.000 individual pixels.

Sync
In video, a means of synchronising signals with timing pulses to ensure that each step in a process occurs at exactly the right time. For example, Horizontal Sync determines exactly when to bring each horizontal line (sweep) of the electron beam. Vertical Sync determines when to bring the electron beam to the top-left of the screen to start a new field. There are many other types of sync in a video system. (Also called Sync Signal or Sync Pulse).

TFT
Thin Film Transistor. A technology used with LCD screens also known as Active Matrix.

UXGA
1600x1200 (4:3 ratio) Giving a total display resolution of 1.920.000 individual pixels.

VGA
640x480 (4:3 ratio) Giving a total display resolution of 307.200 individual pixels. (Video Graphics Array)

WXGA
1280x800 (16:10 ratio) Giving a total display resolution of 1.024.000 individual pixels.

WSXGA
1600x900 or 1680x1050 Defines a class of SXGA displays with a width resolution sufficient to create an aspect ratio of 16:9. A WSXGA display has

WSXGA+
1680x1050 (16:10 ratio) Giving a total display resolution of 1.764.000 pixels.

WUXGA
1920x1200 (16:10 ratio) Giving a total display resolution of 2.304.000 pixels.

XGA
1024x 768 (Extended Graphics Array) (4:3 ratio) Giving a total display resolution of 783.360 individual pixels.

Y
"Y" is an abbreviation for luminance (in video).

Y/Pb/Pr
See Component video.

Zoom Lens
A lens with a variable focal length providing the ability to adjust the size of the image on a screen by adjusting the zoom lens, instead of having to move the projector closer or further.