Definition of scanner

device that can read or scan typed characters from paper (hard) copy and automatically transfer this information onto something else.

1. a device that enables a computer to read a printed or handwritten page. The simplest scanners give the contents of the page to the computer as a graphic image-a handy way of putting pictures into the computer (see desktop publishing. There are four main types of scanners:
   1. Hand-held scanners are inexpensive and adequate for inputting sketches into a draw program. But they have some difficulty scanning images wider than they are; the image has to be scanned in two or more passes and then assembled into one file.
   2. Page scanners accept loose sheets of paper and generally include good software for graphical input and optical character recognition.
   3. Flatbed scanners are the next step up; they can scan pages in books without requiring the page to be fed through the machine. This type of scanner is reasonably priced and generally suitable for all the desktop publisher's needs.
   4. Drum scanners are expensive but give results superior to the other types of scanners. Some service bureaus have drum scanners and can scan artwork or photographs for you.

   There are many nuances involved in scanning artwork. In some ways, it is quite similar to photography and if you are comfortable with a camera, it will make the transition to working with a scanner very smooth. Scanners can adjust the contrast and brightness of the image. Controls for setting the highlight and shadow area are usually provided. Color images can be color-corrected at the scanning stage.

   With appropriate software, scanners can read the letters of typewritten text, transmitting them into the computer as if they were typed on the keyboard ( OCR. This process, however, is seldom 100% accurate. You will find it necessary to proofread scanned copy very carefully.

2. Several other kinds of electronic devices are called scanners, including bar code readers (see bar code) and devices for scanning the radio spectrum.

optical character recognition machine consisting of a scan head, a computer processor, and an output device. The scan head reads a scannable image which is then interpreted by the computer and output in a usable format. For example, a direct-mail marketer might use a scanner to read invoices that have been returned with payment checks. The scanner picks up a code on the invoice that indicates which customer is making the payment and how much was owed. The computer then formulates an instruction to the customer file that the customer's record should be marked paid.

Scanners come in a variety of forms capable of reading preprinted alphanumeric characters in specific fonts, bar codes, or hand-printed letters or symbols. Payment scanners, called encoders, can scan an alphanumeric scan line on invoices and can encode and endorse the checks at the same time. Document scanners that can read at speeds of 18,000 documents per hour are used to enter responses to directmail promotions. Wand scanners are used to read barcoded merchandise information such as stock number and price. With the use of barcodes, prices can be changed, without changing price tags, merely by changing the instructions in the computer system that interprets the barcodes.