Scanning Devices of Computer

Scanning devices include bar-code readers, marl-and character recognition device, fax machines, and imaging systems. Mark and character recognition devices include magnetic –ink character recognition, optical mark recognition, and optical character recognition. Fax machines may be dedicated machines or fax modems. Imaging systems convert text and images to digital form. 

Scanning devices translate images of text, drawings, photos, and the like into digital form. The images can then be processed by a computer, displayed on a monitor, stored on a storage device, or communicated to another computer, scanning devices include:

1. Bar-code readers 
2. Mark-and character-recognition devices 
3. Fax machines 
4. Imaging systems 

Bar-code Readers 

Barcodes are the vertical zebra-striped marks you see on most manufactured retail products-everything from candy to cosmetics to comic books. In North America, supermarkets, food manufacturers, and others have agreed to use a bar-code system called the Universal Product Code. Other kinds of bar-code systems are used on everything from Federal Express packages to railroad cars. Bar codes are read by bar-code readers, photoelectric scanners that translate the bar code symbols into digital forms. The price of a particular item is set within the store’s computer and appears on the sales-clerk’s point of sale terminal and on your receipt. Records of sales are input to the store’s compute and used for accounting, restocking store inventory, and weeding out products that don’t sell well. A recent innovation is the self scanning bar-code reader, which grocers hope will extend the concept of self service and help those lower costs. Here customers bring their groceries to an automated checkout counter, where they scan them and bag them. They then take the bill to a cashier’s station to pay. To guard against theft, the bar-code scanner is able to detect attempts to pass off steak as peas.

Mark-Recognition and Character-Recognition Devices There are three types of scanning devices that “read” marks or characters. They are usually referred to by their abbreviations MICR, OMR, and OCR.
Magnetic –ink character recognition: magnetic-ink character recognition reads (MICR) the strange-looking numbers printed at the bottom of checks. MICR characters, which are printed with magnetized ink, are read by MICR equipment, producing a digitized signal. This signal is used by a bank’s reader/sorter machine to sort checks.

Optical Mark Recognition: optical mark recognition (OMR) uses a device that reads pencil marks and coverts them into computer usable form. The most well-know example is the OMR technology used to read the College Board Scholastic Aptitude Test and the Graduate Record Examination.

Optical character recognition: Optical character recognition (OCR) uses a device that reads special preprinted characters and converts them into machine readable form. Examples that use OCR characters are utility bills and price tags on department store merchandise. The wand reader is a common OCR scanning device.

Fax Machines
A fax machine- or facsimile transmission machine- scans an image and sends it as electronic signals over telephone lines to a receiving fax machine, which re-creates the image on paper.

Dedicated fax machines 

Generally called simply “fax machines,” dedicated fax machines are specialized devices that do nothing except send and receive fax documents. They are found not only in offices and homes but also alongside regular phones in public places such as airports. For the status conscious or those needing t works from their cars, fax machines can be installed in an automobile. The movie the player, for example, contains a scene in which the stalker of a movie studio executive faxes a threatening note. It arrives through the fax machine housed beneath the dashboard in the executive’s range rover. The scanner in a fax machine can also be used to scan graphics and other items and then send them to a computer to be saved as an electronic file and later manipulated.

Imaging systems 

An imaging system- or image scanner or graphics scanner coverts text, drawings and photographs into digital form that can be stored in a computer system and then manipulated. The system scans each image with light and breaks it into light and dark dots, which are then converted to digital code. An example of an imaging system is the type used in desktop publishing. This device scans in artwork or photos that can then be positioned within a page of text. Other systems are available for turning paper documents into electronic files so that people can reduce their paperwork. Imaging system technology has led to a whole new art or industry called electronic imagine. Electronic imagine is the combining of separate images, using scanners, digital cameras, and advances graphic computer. This technology has become an important part of multimedia.