Data Scanning Devices
- 2. Data Scanning Devices Input devices that enable direct data entry into a computer system from source documents Eliminate the need to key in text data into the computer Due to reduced human effort in data entry, they improve data accuracy and also increase the timeliness of the information processed Demand high quality of input documents Some data scanning devices are also capable of recognizing marks or characters
- 3. Image Scanner Input device that translates paper documents into an electronic format for storage in a computer Electronic format of a scanned image is its bit map representation Stored image can be altered or manipulated with an image-processing software
- 4. 2 Common Types of Image Scanners Flat - bed Scanner Hand - held Scanner
- 5. Flat - bed Scanner Looks Like a photocopy machine Has a box with a glass plate on the top & a lid. Document to be scanned is placed on the glass plate. A light source below the glass plate moves from 1 line to the another & scans all the lines. Takes few seconds to scan a document.
- 6. Hand – held Scanner Contains LEDs & can be held in hand. To scan, dragged slowly over the document from 1 end to another. Has to be dragged very slowly & steadily. Used only when high accuracy is not needed. Cheaper than a flatbed scanner. Used when volume of documents to be scanned is low.
- 7. Limitations of Image Scanners Scanned document is stored as an image & not as text. So it is not possible to do any word processing of the document. Storage space required is more for an image than text.
- 8. OCR – Optical Character Recognition Scanner with a character recognition software (called OCR software ) that converts the bit map images of characters to ASCII codes Enables word processing of input text and also requires less space for storing the document OCR software is extremely complex because it is difficult to make a computer recognize an unlimited number of fonts Two standard OCR fonts are OCR-A (American standard) and OCR-B (European standard)
- 9. OPTICAL CHARACTER RECOGNITION OCR-A FONT OCR-B FONT
- 10. OMR – Optical Mark Reader Scanner capable of recognizing a pre-specified type of mark by pencil or pen Very useful for grading tests with objective type questions, or for any input data that is of a choice or selection nature
- 12. OMR Sheet
- 13. BAR CODE READER SUPPLIER IDENTIFICATION NUMBER SPECFIC PRODUC-T CODE NUMBER
- 14. Bar Code Reader Scanner used for reading (decoding) bar-coded data Bar codes represent alphanumeric data by a combination of adjacent vertical lines (bars) by varying their width and the spacing between them Scanner uses laser-beam to stroke across pattern of bar code. Different patterns of bars reflect the beam in different ways sensed by a light-sensitive detector Universal Product Code (UPC) is the most widely known bar coding system
- 15. An Example
- 16. MICR – Magnetic Ink Character Recognition MICR is used by banking industry for faster processing of large volume of cheques Bank’s identification code (name, branch, etc.), account number and cheque number are pre-printed (encoded)using characters from a special character set on all cheques Special ink is used that contains magnetizable particles of iron oxide MICR reader-sorter reads data on cheques and sorts them for distribution to other banks or for further processing
- 18. Digitizer Input device used for converting (digitizing) pictures, maps and drawings into digital form for storage in computers Commonly used in the area of Computer Aided Design (CAD) by architects and engineers to design cars, buildings medical devices, robots, mechanical parts, etc. Used in the area of Geographical Information System(GIS) for digitizing maps available in paper form
- 19. Electronic Card Reader Electronic cards are small plastic cards having encoded data appropriate for the application for which they are used Electronic-card reader is used to read data encoded on an electronic card and transfer it to the computer for further processing Used together as a means of direct data entry into a computer system Used by banks for use in automatic teller machines(ATMs) and by organizations for controlling access of employees to physically secured areas
- 20. Speech Recognition Devices Input device that allows a person to input data to a computer system by speaking to it Today’s speech recognition systems are limited to accepting few words within a relatively small domain and can be used to enter only limited kinds and quantities of data
- 21. Uses of Speech Recognition For inputting data to a computer system by a person in situations where his/her hands are busy For data input by dictation For authentication of a user by a computer system based on voice input For limited use of computers by individuals with physical disabilities
- 22. Vision - Input Systems Allow computer to accept input just by seeing an object. Input data is normally an object’s shape and features in the form of an image.