Scanners - Hardware Concepts

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Scanners

Defining Scanner Types

Scanners are peripheral devices used to digitize (convert to electronic format) artwork, photographs, text, or other items from hard copy. In a sense, a scanner works as a pair of eyes for your PC. Your eyes see an image and translate the image into electrical impulses that travel to and are interpreted by your brain. Similarly, a scanner captures images and converts them to digital data that travel to and are interpreted by the computer.

A scanner works by dividing an image into microscopic rows and columns and measuring, like the film in a camera, how much light (or lack thereof) reflects from each individual intersection of the rows and columns. Each reflection is recorded as a dot, or picture element (pixel). After the scanner collects information from each dot, it compiles the result into a digital file on the computer.

There are a wide variety of scanners that work in a number of different ways, but the technology behind them is essentially the same. The following sections discuss the more popular types of scanners available today.

Types Of Scanners

Flatbed Scanners

Flatbed scanners look and behave a lot like a photocopier. You lay the item to be scanned on a glass plate and the scanning head passes below the glass.

Flatbed scanners are very versatile: you can scan objects in a variety of sizes and shapes, including pages from a book, without damaging the original. While flatbed scanners are the best choice for a wide variety of uses, if you plan to do a lot of text scanning (called OCR for Optical Character Recognition) work, keep in mind that flatbeds only accommodate one page at a time. Scanning multi-page documents can be a slow, tedious process, because you have to manually remove one page and insert the next.

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