A scanner is a computer peripheral device that uses a moving array optical sensors that analyzes images, photos, printed text, handwriting, bar codes, drawings, or a 3D object by detecting the intensity (shades of gray/black/white) and chroma (colors) of extremely small elements (equal to the hardware resolution of the scanner) in the scanned original and converts it to a digital image. Most scanners today are variations of the desktop (or flatbed) scanner. The flatbed scanner is the most common, although sheetfeed scanners (sheetfed) are also widespread (included in All-In-One Printer/Scanner/Fax combo devices). Hand-held scanners, is a device where the device is moved by hand. Another category of scanner is a rotary scanner, used for high-speed document scanning. This is another kind of drum scanner.
Other types of scanners are planetary scanners, which take photographs of books and documents. 3D scanners are used for producing three-dimensional models of objects. Bar code scanners are typically hand-held devices used in retail and wholesale applications - couple bar code scanners with bar code software for a complete end to end solution. Photo scanners (both flatbed and sheet fed) are now extremely popular as consumers switch over to digital imaging from traditional photography. Business card scanners allow for an easy way to capture contact information directly from printed business cards. Slide and film scanners can scan directly from transparencies or photographic negatives.
Hewlett Packard HP scanners are some of the most popular, but other manufacturers are also widespread, such as: Adesso, CardScan, Epson, Fujitsu, Kodak, Microtek, Nikon, Panasonic, Plustek, Visioneer, Wasp, and others.
Another category of scanner is digital cameras. Due to increasing resolution and new features such as anti-shake, digital cameras have become an attractive alternative to regular scanners. While still containing disadvantages compared to traditional scanners, digital cameras offer unmatched advantages in speed and portability.