Scanners are input devices that are used to capture images, documents, posters and other similar sources into the computer for editing or for display. Scanners come in various types, hand-held, flatbed, or scanning black and white only. High-resolution scanners recognise more colors and are used for high-resolution printing and for creating posters, brochures etc. Low-resolution scanners are adequate for normal tasks like scanning an image or document.
The factors to check for when purchasing a scanner are the DPI (dots per inch)-the scanning resolution, number of colors and scanning speed.
Scanners can also be used for Optical Character Recognition (OCR), that is, the ability to recognize the text on a scanned document, thereby possibly allowing to directly modify the contents of the documents in a word processor.
Some of the prominent companies that manufacture scanners are Hewlett Packard, Canon, Microtek and Epson.