Scanner

It is an input device; it is used to read the contents of document and to send data into the primary memory of computer. It is used for direct inputting of the concerns of a file there are two types of scanner.

(1) Optical Scanner      (2) Magnetic Scanner

     

1) Optical Scanner: - A scanner which reads information using light rays is called an optical scanner such as –OMR, OCR

2) Magnetic Scanner: - A scanner which creates magnetic field to read information is called magnetic scanner such as MICR

(a)  OMR (Optical mark Reader): - It is a special type of optical scanner which is used to check the answer sheet of multiple choice Question is scanned than it determines whether the mark is present on that answer and display the status of result sheet also.

(b)  OCR (Optical Character Recognition): - It is a type of optical scanner is an improved model of OMR. It is used to sent typed document hand written document and drawing to the memory of computer. Using OCR the shape and size of document can be recognized.

(c)  MICR (Magnetic Ink Character Recognition): - It is a magnetic scanner. It is used by bank to check the validity of draft. Whenever a draft is scanned it creates high magnetic field on draft and then reads draft number. By using this bank staff determines whether the draft is valid or not.

A scanner may refer to any of the following:

1. When referring to hardware, a scanner or optical scanner is a hardware input device that optically "reads" and image and converts it into a digital signal. For example, a scanner may be used to convert a printed picture, drawing, or document (hard copy) into a digital file which can be edited on a computer. The picture shows an example of a flatbed scanner, the Epson V300.

How is a scanner connected?

A scanner can be connected to a computer using many different interfaces although today is most commonly connected to a computer using a USB cable.

· Firewire

· Parallel

· SCSI

· USB

Other types of computer scanners

There are also other types of scanners that can be used with a computer.

· Sheetfed scanner - scans paper by feeding it into the scanner

·   Handheld scanner - scans text and images by dragging the device over the page you want to scan

· Card scanner - designed to scan business cards

Note

A handheld scanner should not be confused with a bar code reader

When was the first scanner created?

The earliest forms of scanners appeared in the 1860s. However, the scanner as we know it today was created in 1957 by a man named Russell Kirsch at the United States National Bureau of Standards. The first image scanned by this device was a picture of Kirsch's son. This black and white image measured only 5x5 cm and had a resolution of 176 pixels on each side.

Why is a scanner an input device?

A computer scanner is a digitizer, which is a type of input device. It takes information from the real world (e.g., a document or picture) and converts it into digital information for a computer to store or manipulate. A scanner is only able to send information to the computer and cannot receive information from the computer like a printer (which is an output device).

2. When referring to software, a scanner may refer to any program that scans computer files for errors or other problems. An example is an antivirus program, which scans the files on the computer for viruses or other malware.