Digital Imaging

Written by Helen Glenn Court
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What is digital imaging? In sum at its simplest, it is nothing more than a new media for visual communications. In the beginning there were cave walls, stone, wood, bone, animal skin, and textiles. Then came metal, paper, canvas, and film. Today we have microprocessors, circuit boards, optical drives, LCD screens, and binary data. To understand digital imaging one must accept the principle of computer technology.

Digital imaging entails reproducing and manipulating and storing binary representations of three-dimensional objects. It means transferring documents and artwork and photographs to digital format on a computer. It includes creating visual images of all types on a computer in binary format. Typical commercial and service industry applications include medicine, architecture, the movie industry, engineering, art, and photography. But those are just the beginning.

Digital Imaging: Painting by Number

"How is all this actually done?" you ask. "How does it work?" All computer data is binary code, that is, a series of zeros and ones, a mathematical and electronic representation of nonmathematical and physical information. Digital images are defined, that is, mapped on a symmetrical grid, which is nothing more than electronic graph paper. The squares of the grid are called pixels, which is essentially an acronym for picture element. Each pixel is assigned a tonal value. The combination and arrangement of these make up the digital image.

The quality of a digital image is determined by several measurable factors. The first is resolution, which means the number of pixels used to map the image. Resolution is measured by height and width. The second is the bit depth of the pixels. This depth refers to the number of bits (zeros and ones) that are used to quantify the dynamic range of an image (the darkest and lightest values) and its potential tonal values. The higher the resolution and the greater tonal range the pixels have, the better the image.

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