Input devices 2

Input devices 2

1. OCR- Optical Character Recognition

   • How? scanner used to read the reflected light from characters on a page. The scanner creates an image of the character then software atches it again a 'library' of similar character shapes.
   • EG input 'hard copy' into digital format, input data capture forms eg passport
   • Strength: faster than typing/ Limitation: not 100% accurate, all docs need to be manually corrected, not good at capturing hand written text

2. OMR- Optical Mark Reader

   • How? Works like OCR but it reads marks made a specified points on specially designed form. The marks represent pre-set values and once read can be sent for processing
   • EG multiple choice exams, the lottery, school registers
   • Strength:avoids file transfer, quick / Limitation: limit responses, data can be rejected

3. Sensors

   • How? read changed in the environment around them.
   • EG temperature, pressure, light (control systems) movement in a security system
   • Strength: necessary in any control system, cheap and with little human effort./ Limitation: limited data type, can 'misread' an environment eg car alarm activated due to wind.

4. Touch Screens

   • How? values are associated with different positions on a VDU via a 'grid' of infrared beas across the front on the screen.
   • EG museums and galleries, small children and people whose disabilities may prevent them using other input devices, fast food outlets
   • Strength: user friendly/ Limitation: limited as input devices, only a limited number of values can be displayed at one time

5. Speech Input

   • How? data is inputted in audio form (directly- microphone or indirectly- audio tape), software analyses the inputted sound and matches it against library of sounds
   • EG voice recognition systems, control systems
   • Strength: a user can speak much quicker than someone could type/ Limitation: often doesn't understand different accents and styles

6. IWB- interactive white board

   • How? computer connected to projector and white board. Projector displays the computer screen image onto the board. Action on the surface of the display panel is communicated with the computer over a cable or wireless connection and interpreted via the installed softwars
   • EG Schools, businesses
   • Strength:easy, broaden e-learning, enhance presentations/ Limitation: expensive to buy and maintain, break easily