|What is it?||Types||How does it work?|
What is a 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.
Important Note: 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 resolution.
Color vs Grayscale
Gray Scale: Using black and white and shades of gray, the scanner is able to translate the image into gray scales. Why would you use a gray scale scanner? If you plan to print on a black and white printer, it is most cost effective since color ink is so expensive. Text is best done on a grayscale scanner.
Color: A color scanner scans images in red, blue, and green shades. This scanner is more expensive in terms of final print output . A color scanner usually costs more than a gray scale scanner. If you plan on doing presentation work, work with color photographs, or any sort of task that requires a color output, then use a color scanner. With this scanner you can also choose options of scanning such as line art (scanning the image only in black or white), grayscale (black, white, and shades of gray, or color (shades of red, blue, and green).
How a Flatbed Scanner Works
How A Hand-Held Scanner Works
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