It s a device that captures that image. Scanner came in different types in hand held-feed in and flatbed. And it scan only black and white and with colours. The scanner works with a light underneath the image or document that u have.

A motor is used to move the scan head underneath the page. When the scan head is moving it captures the lights that will be reflected from invidual areas.

The light is bounced into a system mirrors and the pivot keeps the light beams aligned with a lens. The digital information is translated to the pc in a format that a graphics programme can read. The advantages and disvantages of a scanner are

Advantages: it can copy things onto computers then you can ulter the thing you copied.

Flatbed scanners are very accurate and can produce reasonably high quality images any image which is digitised by the scanner can then be included on electronic documents Images once digitised can be enhanced with a graphics application.

Ocr: An ocr is an optical character recognition it is an electronic or mechanical translation of images of hand written type written or printed usually captured by a scanner. It’s used to convert paper books into electronic files. OCR is also used to process checks and credit card slips and sort the mail. Billions of magazines and letters are sorted every day by OCR machines, considerably speeding up mail delivery. There are both of advantages and disvantages of an OCR .Advantages Human-readable

Disvantage: Not accurate because it first compares to a list the one closest is chosen .

A computer mouse with the most common standard features: two buttons and a scroll wheel, which can also act as a third button

In computing, a mouse is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user’s hands, with one or more buttons.

The laser of the optical mouse may bounce off certain colours and shapes on a mouse pad.

  The mouse allows an individual to control a pointer in a graphical user interface (GUI). Utilizing a mouse a user has the ability to perform various functions such as opening a program or file and does not require the user to memorize commands, like those used in a text-based command line environment such as MS-DOS.

Advantages: Can be installed without any installation software.

Disadvantages: They need a flat surface to be used, or else they won’t function.

Touchpad

A touchpad is a pointing device consisting of specialized surface that can translate the motion and position of a user’s fingers to a relative position on screen. Touchpads are primarily used in portable laptop computers, because a standard mouse requires a flat surface near the keyboard not always available outside of a standard computing environment.

A pointing device consisting of a soft pad sensitized to finger movement or pressure and used especially on laptop computers as an alternative to a mouse.

Advantages:

· The pad’s position is fixed relative to the keyboard, and very short finger movements are required to move the cursor across the display screen.

· They are small.

Disadvantages:

· Only available on laptops.

· Smaller surface to move on.

· Left and right keys are more difficult to use that in regular usb mouse.

· Cannot scroll across the screen in one go

Trackball

A trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a cursor.

Before the advent of the touchpad, small trackballs were common on portable computers, where there may be no desk space on which to run a mouse.

 Advantages:

· Small Footprint – even the largest trackball takes less work surface space than is required to effectively use the smallest mouse. 

· Stationary Use – not having to move means a trackball never runs out of work surface, never requires re-positioning, allows fast, continuous scrolling, never needs to be picked up and put it back on the mouse pad. 

· Precise Control – most modern trackballs allow you to control cursor movement with your finger tips or thumb.  Much more precise than the hand and wrist movement required to move a mouse.

· Self Cleaning – while some are better than others, most trackballs require little or no cleaning in normal use.

Disadvantages:

· Trackballs are physically larger than mice (even though they require less space to use), it is harder to find a selection of trackballs in most stores and they are typically more expensive because they are manufactured in lower volume.   Operationally, however, anything a mouse can do a trackball can do as well or better.

http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_of_a_computer_mouse

http://en.wikipedia.org/wiki/Mouse_(computing)

http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_between_an_optical_mouse_and_a_ball_mouse

http://www.computerhope.com/jargon/m/mouse.htm

http://www.answers.com/topic/touchpad

http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_of_touchpad

http://en.wikipedia.org/wiki/Touchpad#Touchpads_in_devices

http://www.trackballworld.com/trackball-faq.html

http://en.wikipedia.org/wiki/Trackball

In computing, a printer is a peripheral which produces a hard copy (permanent readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies.

Types of printers:

Laser printers

A computer printer that uses a laser beam to produce an image on a rotating drum before transferring it to the paper.

Advantages of laser printers:

1)     High resolution

2)     High print speed

Disadvantages of laser printers:

1)     More expensive than inkjet printers

2)     Except for high end machines, laser printers are less capable of printing vivid colors and high quality images such as photos.

3)     Warm up time needed

Impact (Dot-matrix) printers

Creates characters by striking pins against an ink ribbon. Each pin makes a dot, and combinations of dots form characters and illustrations.

Advantages of dot matrix printer:

1)     Can print on multi-part forms or carbon copies

2)     Low printing cost per page

3)     Reliable, durable

Disadvantages of dot matrix printer:

1)       Noisy

2)       Limited print quality

3)       Low printing speed

4)       Limited color printing

Inkjet Printers

Inkjet printers are non-impact printers which print text and images by spraying tiny droplets of liquid ink onto paper.  They are the most popular printers for home use.

Advantages of inkjet printers:

1)     Low cost

2)     High quality of output, capable of printing fine and smooth details

3)     Capable of printing in vivid color, good for printing pictures

4)     Easy to use

Disadvantages of inkjet printers:

1)       Expensive replacement ink cartridges

2)       Not good for high volume printing

3)       Printing speed is not as fast as laser printers

Plotters

A device that draws pictures on paper based on commands from a computer. Plotters differ from printers in that they draw lines using a pen. As a result, they can produce continuous lines, whereas printers can only simulate lines by printing a closely spaced series of dots.

Advantage of plotters:

It can print out anything big

Disadvantage of plotters:

It’s really big so it can take up a lot of space

Printer Characteristics (What you would consider when buying a printer)

Quality of Print – How good is the output quality of text that the printer prints.

Speed – How fast does the printer print. Generally there are different qualities of print. Keep in mind the printer will print slower if set to the highest quality.

Ink / Ribbon – What type of ink and or ribbon does the printer use? How much will it cost to replace? Can it be purchased locally or does it need to ordered from the printer company?

Paper – Does the printer require special paper? How is the printer paper loaded?

Useful Websites:

http://en.wikipedia.org/wiki/Printer_(computing)

http://www.cleverace.com/Printer_types.htm

http://inkjets.4reviews.net/inkjet_printers.htm

http://inkjets.4reviews.net/laser_printers.htm

http://inkjets.4reviews.net/less_popular_printers.htm

http://www.opendrivers.com/resources/c74d97b01eae257e44aa9d5bade97baf.html



A liquid crystal display (LCD) is a thin, flat panel used for electronically displaying information such as text, images, and moving pictures. Its uses include monitors for computers, televisions, instrument panels, and other devices ranging from aircraft cockpit displays, to every-day consumer devices such as video players, gaming devices, clocks, watches, calculators, and telephones. Among its major features are its lightweight construction, its portability, and its ability to be produced in much larger screen sizes than are practical for the construction of cathode ray tube (CRT) display technology. Its low electrical power consumption enables it to be used in battery-powered electronic  equipment. It is an electronically-modulated optical device made up of any number of pixels filled with liquid crystals and arrayed in front of alight source (back light) or reflector to produce images in color or monochrome. The earliest discovery leading to the development of LCD technology, the discovery of liquid crystals, dates from 1888. By 2008, worldwide sales of televisions with LCD screens had surpassed the sale of CRT units.

Characteristics that help you when buying an LCD monitor

• Compatibility
  Make sure the monitor you’re considering has the right connectors for your computer and that your operating system will work with it.
• Quality of the LCD monitor

Advantages in using LCD monitors

• Takes up less space, consumes less power, so it is good for Environment (eco friendly), and produces less heat than traditional cathode-ray tube monitors.

• Lack of flicker and low glare reduce eyestrain.

Disadvantage of LCD monitors

• LCD monitors are very expensive to buy than a CRT

CRT Monitors

CRT stands for cathode ray tube, describing the technology inside an analogue computer monitor or television set. A CRT monitor or TV is readily recognizable by its bulky form. The CRT monitor creates a picture out of many rows or lines of tiny coloured dots. These are technically not the same thing as pixels, but the terms are often used interchangeably. The more lines of  dots per inch, the higher and clearer the resolution. Therefore 1024 x 768 resolution will be sharper than 800 x 600 resolution because the former uses more lines creating a denser, more detailed picture. Higher resolutions are important for displaying the subtle detail of graphics. For text, resolution isn’t as critical.

Advantages in using CRT  monitors

• Significantly lower cost compared to CRTs, because the technology has matured.
• Displays full motion video better
• Modern versions may include a sleep-mode for energy efficiency.
• Strong glass screen can withstand routine handling, and is not easily damaged by casual touch.
• Screen images viewed from side angle are as good as when viewed straight-on (no dilution of clarity or colour.)

Disadvantages  in using CRT  monitors

• Larger size takes up more desk space; the bigger the screen, the bigger     the footprint.

• Heavy weight, 40 lbs and more.

• Heavier size limits easy and convenient movement.
• Expends more energy and throws off heat

The information I found was summarized from the following sites:

http://en.wikipedia.org/wiki/Liquid_crystal_display

http://www.wisegeek.com/what-is-a-lcd-monitor.htm

http://www.pcworld.com/article/15112/how_it_works_lcd_monitors.html

http://www.lcdtvbuyingguide.com/lcdtelevision/3lcdadvantages.shtml

http://compreviews.about.com/od/multimedia/a/CRTvsLCD.htm

http://en.wikipedia.org/wiki/Cathode_ray_tube

http://www.wisegeek.com/what-is-a-crt-monitor.htm

http://www.ergoindemand.com/lcd_and_crt_monitor_comparison.htm

http://www.webopedia.com/TERM/C/CRT.html

http://www.webopedia.com/DidYouKnow/Hardware_Software/2005/all_about_monitors.asp

Definition-

A bar-code reader is a device that read barcodes. All bar-codes contain decoder.  http://en.wikipedia.org/wiki/Barcode_reader

How it works-

 The bar-codes reader have 3 functional parts; the illumination system, the sensor/converter & the decoder. http://www.carolinabarcode.com/how-barcode-scanners-work-a-69.html

Advantages-

 A bar-code reader is very accurate & have speed. http://www.barcoding.com/information/Learn_About_Barcodes.shtml

Disadvantages-

 If a bar-code reader is scratched you will not be able to use it. http://wiki.answers.com/Q/What_are_the_Disadvantages_of_a_bar_code_reader

 Charateristics-

  Bar-codes are not usable in a dirty factory or in outdoor environment. http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F20%2F17822%2F00822548.pdf%3Farnumber%3D822548&authDecision=-203

OCR.

Definition-

 An Ocr recognize many different text and fonts. Ocr system can recognize hand printing. http://www.yourdictionary.com/computer/ocr

How it works-

 Ocr system works by using algorithms to recognize characters & increase accuracy.

http://in.answers.yahoo.com/question/index?qid=20061113001740AAvtIPw

Characteristics-

 The choice of a commercial OCR engine is important for the process of automatically indexing technical drawings. http://www.computer.org/portal/web/csdl/doi/10.1109/ICDAR.2001.953770

Advantages-

Human  readable. http://wiki.answers.com/Q/What_is_OCR_and_Advantages_and_disadvantage_of_OCR

Disadvantages-

 Not accurate, because it first compares to a list then the one closet is chosen. http://wiki.answers.com/Q/What_is_OCR_and_Advantages_and_disadvantage_of_OCR

MICR

Definition-

 Micr is a line at the bottom of a check encodes three or four separate items. http://www.elfring.com/what.htm

How it works-

 Micr encodes this information into magnetic ink & prints it on the bottom of the check where it can be quickly and easily read by automated check sorting machines. http://www.ehow.com/how-does_4898737_micr-work.html

Characteristics-

 Micr technology is almost universally used for processing checks. http://www.ehow.com/how-does_4898737_micr-work.html

Advantages-

 By MICR code a person comes to know about the bank name & branch. http://wiki.answers.com/Q/What_are_advantages_of_a_MICR

Disadvantages-

 Micr readers & printers are expensive and the system can only accept few characters.

A Graphics Tablet also known as Digitizing Tablet ,Graphics Pad or Drawing Tablet is a computer input device. This allows one to hand-draw images and Graphics .These Tablets may also be used to capture data or handwritten signatures.These vary in sizes.

A Graphics Tablet consists of a flat surface upon which the user may ”Draw” an  image  using  an attached stylus ,a pen like apparatus.The image generally does not appear on the  tablet itself  but rather, is displayed on the computer moniter.Some tablets however , come as a functioning secondary computer screen that you can interact  with directly using the stylus.

Some tablets are like a replacement for a mouse as the primary pointing and navigation device for desktop computers.

OMR:

Optical Mark  Recognition also known as Optical Mark Reading  is the process of capturing human-marked data from the document forms such as surveys and tests .This is a software recognizes optical marks bubbles and check boxes,machine-generated characters ocr and barcodes.you can design your own forms using any word processor and print them on your printer.Then use remark office omr to scan and recognize data with your image scanner and analyze the data or export the data to the application of your choice! It’s that easy !

The information i found was summarized from the following sites :

http://en.wikipedia.org/wiki/Graphics_tablet

http://graphicssoft.about.com/od/aboutgraphics/a/graphicstablets.htm

http://animation.about.com/od/glossaryofterms/g/graptab_def.htm 

   :http://en.wikipedia.org/wiki/Optical_mark_recognition 

http://www.gravic.com/remark/officeomr/

http://microlab.uwyo.edu/Documentation/OMR/default.htm

http://dictionary.reference.com/browse/Optical+Mark+Reader

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To keep our work organised see that you add the appropriate category to each post.

I’ll be giving you a number of Input or Output devices, which you will need to research and present to your class. Any idea what Input / Output devices we may be considering ?

Was there any particular question which you found tricky ?