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 photo 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.
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 barcode 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 an input device because 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. A good example is an anti-virus program, which scans the files on the computer for viruses or other malware.