Scanners

Scanners  Back Scanners convert printed data or images into an electronic data format that a computer can store or process as required. A scanned image can be saved, modified, and even e-mailed as you would with any other file.

Resolution and OCR

Features, quality, and speed of scanners vary. Scanners typically create an RGB image that can be converted into image formats such as JPEG, TIFF, Bitmap, and PNG. An RGB image has three channels: red, green, and blue. Some scanners can create text documents using optical character recognition (OCR). OCR software is used to convert a scanned printed page into text that can be edited with a word processor.Resolution of a scanner is measured in dots per inch (dpi). Like printers, the higher the dpi, the better the quality of the image.



Interface and cable

To allow communication of data, the scanner and computer must have compatible interfaces. Interfaces and cables used for printers are typically the same as those used for scanners. Such as: parallel and serial.

Types of scanners

· All-in-one

An all-in-one device combines the functionality of multiple devices into one physical piece of hardware. It includes: Scanner, Printer, Copier, and/or Fax
 * __Advantages:__ all devices are built in, low cost, one upgrade for all devices, easy connection and setup and Uses one port for all devices.
 * __Disadvantages:__ one problem effects all devices and not designed for heavy use.



· Flatbed scanner

It Often used to scan books and photographs for archiving.Image is acquired by placing the document face down on the glass. The scanner head lies beneath the glass and moves along the item, capturing the image. · Maintenance: keep flatbed scanning glass clean and avoid placing items in the scanner that can scratch the glass.



· Handheld scanner

<span style="font-family: Georgia,serif; font-size: 120%;">It passes the scanner head across the surface you want to scan. When you want to scan an item larger than the head of the handheld scanner, you must make more an one pass to capture the full image and then put the images back together to form a single image of the item that was scanned.



· <span style="font-family: 'Comic Sans MS',cursive; font-size: 12pt;">Drum scanner

<span style="font-family: Georgia,serif; font-size: 120%;">It produces a high-quality scanned image. It usually used in commercial operations. Now it is being replaced by lower priced, high-quality flatbed scanners. Drum scanner stills in use for high-end reproductions, such as archiving photographs in museums. To scan an image using a drum scanner: <span style="font-family: Georgia,serif; font-size: 120%;">Attach the image to a revolving drum or load it into a supporting canister.



<span style="font-family: Georgia,serif; font-size: 120%; line-height: 0px; overflow: hidden;"> <span style="font-family: 'Comic Sans MS',cursive; font-size: 14pt;">Summary

<span style="font-family: Georgia,serif; font-size: 120%;">Scanners digitize the images or documents to be stored as a file. This file can be displayed, printed or even altered. Scanners create an RGB image which can be converted to many formats such as JPEG and TIFF. Some of them have the ability to create a text document using Optical Character Recognition (OCR). As with printers, most of scanners are attached with computers by parallel ports. Their quality also measure by dot per inch(dpi). <span style="font-family: Georgia,serif; font-size: 120%;">There are many types of scanners that vary in their features: <span style="font-family: Georgia,serif; font-size: 120%;">· All in one: it combines multiple devices into one physical device. This device generally includes the functions of: scanner, printer, fax and copier.

<span style="font-family: Georgia,serif; font-size: 120%;">· Flatbed scanner: it provides a flat glass surface to hold the documents for scanning.

<span style="font-family: Georgia,serif; font-size: 120%;">· Handheld scanner: it is small and portable scanner that used to read the bar code on the objects.

<span style="font-family: Georgia,serif; font-size: 120%;">· Drum scanner: it used to scan high resolution images, to scan the image; we attach it to a revolving drum.

<span style="font-family: 'Comic Sans MS',cursive; font-size: 12pt;">Resource

<span style="font-family: Georgia,serif; font-size: 120%;"> <span style="font-family: Georgia,serif;">CISCO Networking Academy Program Website