Pixel• The word "pixel" was first

published in 1965 by Frederic C. Billingsley of JPL, to describe the picture elements of video images from space probes to the Moon and Mars.

• Each pixel is a small quantity of an original image; more samples typically provide more accurate representations of the original.

Pixels and Colour

Colour Depth1 bit colour4 bit colour8 bit colour24 bit colour

No. Of Colours21625616,777,216 or True Colour

• LCD pixels are manufactured in a two-dimensional grid, and are often represented using dots or squares, but CRT pixels correspond to their timing mechanisms and sweep rates.

Converting Light - Cameras

When a picture is taken there is a small device inside which forms all the similar colours and combines them to make the picture and if you look closely on any picture you will see hundreds of small squares.

Resolution

The standard for screen displays is 72 PPI.

The standard for Print is 300 PPI.

Vector Images

• Vector (composed of paths) • The vector graphics use mathematical

points connecting together to make up the image

• Vector images is a lot clearer than raster images

Raster Images• Raster (composed of pixels) and

more commonly known as bitmap images

• A Raster image uses a grid of separate pixels which are each a different colour and shade.

• A raster is a lot more blurry than Vector images.

Antialiasing

• In computer graphics, antialiasing is a software technique for diminishing jaggies - stair step-like lines that should be smooth. Jaggies occur because the output device, the monitor or printer, doesn't have a high enough resolution to represent a smooth line.

Aspect Ratio• The aspect ratio of an image is the

ratio of the width of the image to its height

• Aspect ratio is expressed as two numbers separated by a colon. That is, for an x:y

• In objects of more than two dimensions, such as Hyperrectangles, the aspect ratio can still be defined as the ratio of the longest side to the shortest side.