Optical Scanner

1) What is it?

An optical scanner is any scanning technology that converts an image, text, or object into a digitized form that can be stored as 2D or 3D image files on a computer, and can be manipulated by programs. However optical scanners can not distinguish between text, and illustrations because it represents all texts and images as bit maps. One can’t directly edit a scanned object.

2) What is it for?

Optical scanners are used for recording light, dark, and colored areas of scanned text, and images. This is because it uses a technology which is sensitive to light. To edit text and images captured by an optical scanner, the user needs an optical character recognition (OCR ) system to translate the image into ASCII characters.

Optical scanners differ in scanning technology, resolution, bit depth, size and shape. These differences also direct their usage, and purpose. For example:

Larger scanners are also called sheet-fed scanners. These are used for loose sheets of paper, but they are unable to handle bound documents.

A Flatbed Scanner, another example of a large scanner, is like a photocopy machine. It consists of a board on which you lay books, magazines, and other documents that you want to scan.

Overhead Scanners or Copy board scanners look somewhat like overhead projectors. Users can place documents on a scanning bed, and a small overhead tower moves across the page.

http://www.webopedia.com/TERM/O/optical_scanner.html (accessed on Aug. 6, 2009)

http://www.wisegeek.com/what-are-optical-scanners.html

3) What does it look like?

Charge-coupled device (CCD) arrays are what most scanners use, which consist of tightly packed rows of light receptors that can detect variations in light intensity and frequency. The quality of the CCD array is probably the single most important factor affecting the quality of the scanner. Industry-strength drum scanners use a different technology that relies on a photomultiplier tube (PMT), but this type of scanner is much more expensive than the more common CCD -based scanners.

http://www.webopedia.com/TERM/O/optical_scanner.html August 6, 2009

4.) The technology used in most optical scanners is called charge-coupled device (CCD) arrays. The instrument has its semiconductors connected to one another so that the output of one semiconductor becomes the input of the next one. It is used to detect variations in light intensity and frequency. A high quality CCD makes for a high quality scanner. The PMT (photomultiplier tube) is another technology used for scanners. It is much more expensive than CCD and thus, only industry-strength drum scanners use this. Source http://www.webopedia.com/TERM/O/optical_scanner.html (accessed August 6,2009)