SCANNER

Scanners allow a pc to convert a picture or object into digital code that allows the computer to display and use an image. A scanner's sophistication is the ability to translate an unlimited number of analog voltage levels to digital values. The computer is not able to use graphics unless they are in a form that they can understand. The scanner takes the information it sees on a page and converts into code that the computer can use. A picture once scanned can be edited, printed, or used in an application. Scanners can come with specialized software called optical character recognition (OCR). This software can read text as printed or written. The information can then be manipulated in the computer.
Scanners usually attach to your personal computer with a Small Computer System Interface ( SCSI ). An application such as PhotoShop uses the TWAIN program to read in the image.
A feature of the scanner is the resolution. This is how sharp and detailed the scanner can read. Scanners are measured in dots per inch. The higher the resolution, the more the memory that is required to scan the file. The bigger the file that is produced. Larger files take longer scanning time. If a file is big and you need to fit it on a diskette, you may run into a problem storing it unless you store it to the hard drive or another high capacity drive. Therefore, if you are wanting to produce a file for screen output, you should scan at 72 dpi because that the best resolution that the monitor can display. It is the same of the printed output. If you only have a 300 dpi printer, do not scan the file at a higher resolution since the printer will only print it at that resolutionSheet-Fed Scanner Sheet-fed scanners have mechanical rollers that move the paper past the scan head. Flatbed Scanner Flatbed Scanners have a glass window where the item to be scanned is placed on top of a while the head moves past the item. This method is similar to a xerox machine. Hand Held Scanners Hand held scanners are small, portable scanners that depend on a human operator to move the head across the the object or image to be scanned