Scanner Scanner Introduction Scanner is an input device

Scanner

Scanner Introduction: • Scanner is an input device. • It reads the graphical images or line art or text from the source and converts it into digital information and send it to the computer. • Scanner is electronic device that scans data. • Scanners are used to give large volume of data as input to the computer.

• Specification of scanner: – Scan speed photo color, 10*15 cm, OCR A 4 – Optical resolution 4800 dpi*9600 dpi – Min temperature: 50 to 95 degree. – Operating humidity range: 15 -85% – OS: windows, Mac. OS, windows 7/8/XP/2000. – Power supply: 15 W – Port required: hi-speed USB

Types of scanner Flat bed scanners Sheet fed scanners Hand held scanners Drum scanners

Flat bed scanners Sheet fed scanners Hand held scanners

Operation • Scanner is operates on the principle of reflection. • That is , when a light source falls on an image document , the incident light reflects. • The reflection depends upon the color and size of the images in the document.

Structure of Scanner • That is black or white spaces reflect more light than colored or inked letters or images.

Cont. , • The light from the lamp is made to fall on the document through the glass plate. • The head receives the reflected light from the document with the help of mirrors (m). • The reflected light is filtered with the help of R, G, B filters.

Cont. , • The filtered light is made to fall on a light sensor having 1024 elements using a mirror and a lens. • The sensor converts the analog signals into digital signals and is given as output. • The scan head is moved over the document with the help of a motor.

Scan Resolution • The number of dots or pixels per inch a scanner can resoluve for a document. • In other words resolution relates to the fineness or clarity of the image scanned by the scanner.

Different Resolutions 200 dpi – Dots Per Inch 400 dpi 600 dpi and so on. • The more dots per inch a scanner can resolve, the more clarity the resulting image will have.

Flatbed scanner • Scan documents, photos, flat object from a PC or laptop. • Works like copy or Xerox machine. • Flatbed is made up of glass pane and moving CCD array and two mirrors. • Most common type of scanner easy to operate, widely used.

Flatbed scanner specification • Scanner type: flatbed • Size: 280*486*52 mm • Weight : 1. 7 kg • Interface: USB 1. 0 • H/W reslution: 1200 DPI. • AC voltage: 200 -240 V 50 Hz

Sheet-fed scanner • Sheet-fed Scanner smaller and portable • Used to scan document and photos • Document is fed into horizontal and vertical slot provided with scanner • Components of scanner sheet-feeder, scanning module & calibration sheet. • Scan single page documents. • Not used to scan thicker objects.

Handheld scanner • Smaller in size. • It is scanning device which is moved over the object that needs to be scanned. • To scan the document drag the scanner over document. • Used in barcode scanner. • Image quality is very poor.

Drum scanner • Used in publishing industry. • Color drum scanners use three matched photo multiplier tube. • High resolution high quality. • More Expensive. • Drum scanners are slow.

Scan modes Line art Half toning Gray scale True color