Glossary: Chapter 9

additive primary colors

The three colors, red, green, and blue, of which color computer graphics and color television are composed. Color monitors are equipped with an RGB (red-green-blue) video board to produce their colorful images.

buffer memory

A temporary storage area where the computer stores a set of character-plotting commands in vector graphics before they are transmitted to the screen.

computer animation

The creation and display of computer graphic images in rapid sequence to produce the effect of animation, exemplified in arcade video games.

computer-aided engineering (CAE)

The use of an integrated series of computer processes to design, test, and manufacture products, usually starting with computer-aided design (CAD).

computer-aided manufacturing (CAM)

The use of a computer system to automate parts of a manufacturing process, such as producing machine parts directly on robotic lathes that receive their instructions from a CAD system. The abbreviation CAD/CAM applies to such integrated computer processes.

data glove

A glove filled with sensors to detect body movement and effect change in the simulated world of VR.

digitized video

A process in which a hardware circuit board on a computer accepts input from a TV or VCR and converts the images to digital format at a rate of between 15 and 30 frames a second, capturing full-motion video for the computer screen.

digitizing scanner

A hardware device that converts color or black-and-white images on paper to pixel images so that they may be processed by a computer.

dithering

A process used in some color printers and graphics software to adjust the number of dots of different colors within a matrix of eight pixels to produce many shades.

draw program

A graphics program that provides commands to create regular shapes like rectangles as objects that can be resized or moved around without affecting other objects.

electrostatic plotter

A plotter that uses electricity to transfer bit-mapped images to paper by printing raster pixels line by line, much as they are produced on a bit-mapped printer.

fax machine

A machine that scans documents and transmits them to either computers or other fax machines over a phone line.

flatbed plotter

An output device that works on the vector principle. It accepts instructions from a computer about where to draw a line, how long it is to be, and where to stop or turn in another direction and moves its drawing pen accordingly.

four-color process

The printing process used in color printing with laser printers, as well as in color book and magazine production. It is sometimes denoted by the initials CMYK (cyan, magenta, yellow, black), standing for the three subtractive colors, plus black, that are blended to create colored materials in print.

fractal geometry

A field of mathematics pioneered by Benoit Mandelbrot that involves the study of a set of infinitely recursive mathematical functions which seem to mirror natural phenomena like leaf and cloud formation.

frame buffer

In raster graphics, a special area of RAM that holds the pixel contents of a computer screen.

full-motion video

A term applied to video movies that can be edited and shown on a computer after they are digitized.

graphics primitives

A set of graphic drawing elements like point markers, various types of lines, arcs and curves, circles, and closed polygons, included in software for CAD.

graphics processor

Part of a raster graphics display system that prepares pixel information for the frame buffer.

gray scale

A term applied to the gradations of shadings from white to black that result from attaching an RGB video board to a monochrome screen.

head-mounted display (HMD)

A term for a set of 3-D goggles equipped with CRTs inside for use in virtual reality games or other applications.

interactive computer graphics

A term applied to software and hardware systems that allow complicated graphics repositioning to be carried out in real time, such as in fine CAD systems.

light pen

A handheld input stylus that uses a photocell to transmit signals to a computer screen, first used in CAD applications.

object-oriented graphics software

Draw programs that treat graphic constructions as objects suitable for repositioning and resizing as a unit.

paint software

Graphics programs that allow users to handle prepared shapes or do freehand sketching and manipulate their creations at the pixel level.

photo-realism

A term used to describe the increasingly realistic creations of computer graphics made possible by techniques like ray tracing.

presentation graphics

Software that produces graphic representations of information, often used for presentations at meetings.

radiosity

A software technique to simulate the effects of light diffusion and add shading to objects in computer graphic images that seem sharper than reality.

raster graphics

A common method of presenting computer graphic images on a CRT, based on the technology of television, that uses an electron beam to excite phosphor dots (pixels) inside the CRT screen and make them glow.

raster

A term for the horizontal lines of pixels on a TV or CRT screen, refreshed at a rate of 30 times a second to display an image on the screen.

ray tracing

An enhancement technique for computer graphics that simulates the effect of reflected light rays in a three-dimensional scene on a two-dimensional computer screen.

refresh buffer

In vector graphics, hardware that renews a phosphor-coated display screen with an electron beam to maintain information that would otherwise flicker.

rendering

A general term for creating a ray-traced image.

subtractive primary colors

The three primary colors, magenta, cyan, and yellow, defined by the absence of one of the RGB colors, created by eliminating that color from light reflected from a white page. These colors form the basis of color laser printing.

sweeper

An element of a raster graphics system that takes information from the frame buffer and updates the display screen.

vector graphics

The earliest type of computer graphics, in which a set of character-plotting commands activate the phosphors of a computer display with an electron beam.

video game

One of the most popular and most widely recognized computer graphic applications, available in video arcades and home entertainment software.

virtual reality (VR)

An environment created by computer technology that combines visual, auditory, and tactile interaction to create the illusion of realistic objects and sensory experiences for the user. Also called artificial reality, cyberspace, and tele-presence.

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