Image scanner

A scanner is a device that converts an image located on a flat carrier (most often paper) into a digital format. The process of obtaining such a digital copy is called a scan .

During scanning using an ADC, a digital description of the image of an object external to the computer is created, which is then transmitted through the input-output system to the computer.

Types of scanners

There are hand, roll (English Sheet-Feed ), tablet and projection scanners. A variety of projection scanners are slide scanners designed for scanning photographic films. In high-quality printing, drum scanners are used in which a photomultiplier tube (PMT) is used as a photosensitive element.

The principle of operation of a single-pass flatbed scanner is that along a scanned image located on a transparent fixed glass, a scanning carriage with a light source moves. The reflected light through the optical system of the scanner (consisting of a lens and mirrors or a prism) falls on three CCD-based photosensitive semiconductor elements parallel to each other, each of which receives information about the components of the image.

Story

Scanning technology

In 1857, the Florentine abbot Giovanni Caselli (Italian: Giovanni Caselli) invented a device for transmitting images over a distance, later called pantelegraph . The transferred picture was applied to the drum with conductive ink and read with a needle.

In 1902, the German physicist Arthur Korn (pp. Arthur Korn ) was patented photoelectric scanning technology, later called the telefax . The transmitted image was fixed on a transparent rotating drum, a beam of light from a lamp moving along the axis of the drum passed through the original and through a prism located on the axis of the drum and the lens hit the selenium photoreceiver. This technology is still used in drum scanners.

Later, with the development of semiconductors, the photodetector improved, the tablet scanning method was invented, but the principle of image digitization remains almost unchanged.

Application

Scanners are used to enter drawings into a computer, which can immediately be processed in a graphical editor. Scanners better introduce a flat image into a computer than digital cameras

see also

• Film scanner
• 3D scanner
• Hand scanner
• Spotlight (graphic editor) - software for wide format scanners
• RasterDesk - software for wide format scanners
• Colortrac - widescreen scanners
• Film scanner
• Optical character recognition
• Continuous scanning of documents