• Scanner:

• An image scanner—often abbreviated to just scanner, is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image.

• Converting a paper document to digital image.

• Scanning bed in the scanner, a glass plate is utilized to place a document for scanning.

• A light source is mounted on a traction mechanism which moves from one end of the document to other end during scan session.

• A mirror is used to reflect each illuminated scan line to fixed CCD array as light source moves across the document.

• The CCD array determines the pixel intensity in the selected line for each pixel across the line.

• Once the scan is complete, the image is transferred to a computer via USB.

• $\underline{Rotary \ Drum \ Scanner}$:

• In case of flatbed scanner at a time we can scan only one side of paper. But mechanism of rotary drum scanner is somewhat different that is in which two digital cameras with CCD array are mounted in a fixed position near the drum.

• As per the name suggest this scanner contains drum to wrap the paper and two set of belts three set roller guides to guide the paper.

• So this rotary drum scanner will scan both the sides of papers in single attempt and scanning mechanism with CCD array is same like flatbed scanner.

• A fixed CCD array absorbs reflected light and generates analog voltage which in turn gets converted to a digital value.

• The front side of the page is scanned in position 1 as it is around the drum and the back side of the page is scanned in position 2 as the transport mechanism pulls the paper from the drum and ejects it out to the stacking tray.

• Hand held document scanners are manual devices that are dragged across the surface of the image to be scanned.

• Scanning documents in this manner requires a steady hand, as an uneven scanning rate would produce distorted images.

• They typically have a "start" button, which is held by the user for the duration of the scan.

• Mainly used to capture a part of page from a book, part of newspaper.

• A handheld scanner can be used for surfaces the have some curve. Mainly, handheld scanners offer portability and the convenience of a simple device at a cost lower than that of a flatbed scanner.

• Handheld scanners use a light bulb as a light source to illuminate the scan line being scanned. The light is reflected from the document as the user moves the scanner across document. A fixed CCD array absorbs the reflected light and generates an voltage, Which in turn gets converted to a digital value.