A digital image is a representation of a real image as a set of numbers that can be stored and handled by a digital computer. In order to translate the image into numbers, it is divided into small areas called pixels (picture elements). For each pixel, the imaging device records a number, or a small set of numbers, that describe some property of this pixel, such as its brightness (the intensity of the light) or its color. The numbers are arranged in an array of rows and columns that correspond to the vertical and horizontal positions of the pixels in the image.

This digital camcorder, unveiled by Matsushita in 2001, features a 200,000-pixel color LCD screen. The camera can store up to 180 still images, which can be transferred to a PC.

Digital images have several basic characteristics. One is the type of the image. For example, a...