COMPUTER STUDIES-7010

Tuesday, May 19, 2009

AUTOMATED INPUT DEVICE

1.     Magnetic Ink Character Recognition:

Each day, banks process millions of cheques. It would take them far too long to manually enter the data from each cheque. They use a technique called 'Magnetic Ink Character Recognition' (MICR) which enables them to process 300 cheques per minute with 100% accuracy.

At the bottom of each cheque are a series of numbers which record:

  • the cheque number
  • the bank or building society sort code
  • the customer's account number

These numbers are written in a special ink which contains iron particles. This ink is magnetised and commonly called 'magnetic ink'. It can be read by a special machine called a Magnetic Ink Character reader (MICR).

The MICR will only recognise numbers printed in a standard font using the magnetic ink. This provides a high level of security because any attempt to alter the magnetic ink printout with normal ink by writing over it will be ignored. Both the Reader and the magnetic ink are expensive and so are generally only used by banks.

2.     Optical Mark Reader:

OMR sheets are scanned by a special piece of equipment called an 'Optical Mark Reader' (OMR). They detect the presence of your pencil mark by reflecting light onto it. Less light is reflected where a mark has been made. The OMR then interprets the pattern of marks and sends the results to the computer for storage, analysis and reporting.

Advantages
  • A fast method of inputting large amounts of data - up to 10,000 forms can be read per hour depending on the quality of the machine used.
  • Only one computer needed to collect and process the data
  • OMR is much more accurate than data being keyed in by a person
Disadvantages
  • If the marks don't fill the space completely, or aren't in a dark enough pencil, they may not be read correctly
  • Only suitable for recording one out of a selection of answers, not suitable for text input.
  • The OMR reader needs the answers to be on the prepared forms which will all be identical to one another. You can't just pick up a blank sheet of paper and mark your answers on it.

3.     Optical Character Recognition:

An OCR system consists of a normal scanner and some special software. The scanner is used to scan text on a document or piece of paper into the computer. The OCR software then examines the page and changes the letters into a form that can be edited or processed by a normal word processing package.

The ability to scan the characters accurately depends on how clear the writing is.

Scanners have been improved to be able to read different styles and sizes of text as well as neat handwriting.

Although they are often up to 95% accurate, any text scanned with OCR needs careful checking because some letters can be misread.

OCR is used to automatically recognise postcodes on letters at sorting offices.

Advantages
  • Cheaper than paying someone to manually enter large amounts of text
  • Much faster than someone manually entering large amounts of text
  • The latest software can recreate tables and the original layout
Disadvantages
  • Not 100% accurate, there are likely to be some mistakes made during the process
  • All documents need to be checked over carefully and then manually corrected
  • If the original document is of poor quality or the handwriting difficult to read, more mistakes will occur
  • Not worth doing for small amounts of text


4.     Barcode Reader:

Most items that are for sale in shops have a barcode printed somewhere on the packaging.

The barcode is a series of vertical bars of varying widths that give information about:

  • the country of manufacture
  • the name of the manufacturer
  • a product code

The barcode does NOT contain the price of the item - this is held on the company database.

A barcode reader is an automatic input device which is used to scan or 'read' the barcode by using a visible red light. The reflected light is translated into digital data that is interpreted by the computer to identify the product and price from the database.

The main advantage of using a barcode system is that any price change only needs to be made to the database and not every single product package.

5.     Magnetic Stripe Reader:

Magnetic strips are usually found of the back of most credit cards, cheque guarantee cards, loyalty cards, membership cards etc.

The magnetic strip can hold personal details about the card number such as account number and name. The strip can contain up to 60 characters, stored magnetically.

To read the data on the card, it is 'swiped' through a Magnetic Stripe Reader machine and the data is read and fed back to the computer.

Advantages
  • Simple to use
  • Cheap to produce
  • Data can be altered if necessary
  • Security has been improved by the use of PIN numbers which must be entered into a machine to confirm that you are the rightful card owner
Disadvantages
  • Very limited storage capacity for data
  • Data can be easily destroyed by strong magnetic fields
  • Not always secure as thieves can obtain the readers and read the data on the card.

6.     Biometric Devices:

There is an increasing trend towards using biometric data from people in order to identify them. Finger print and retinal identification are being used in many places now and even facial recognition systems are starting to be introduced.

Special devices are needed to capture the biometric data which is then passed onto the computer for processing and identification.

Biometric authentification methods can be used to identify you at ATMs to withdraw cash.

 

7.     Sensors :

Sensors are used to detect physical quantities outside a computer such as light, temperature and pressure.

They collect data automatically and usually at regular intervals. This data is can either be transmitted immediately to the computer or can be stored for a period of time and a batch of readings sent in one go.

In order to process input from sensors, a device called an 'Analogue to Digital Converter' (ADC) must be connected between the computer and the sensor. This device converts the analogue signals from the sensors to digital data that the computer can process.

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