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Unit 5: Computer Hardware

Figure 5.13: A Sample of Answer Sheet
that is Checked by Optical Mark Notes
Reader (OMR).

A B C D

1

2

3

4

5

Optical Character Reader (OCR)
Optical Character Reader is an optical scanner, which is capable of detecting alphanumeric characters
typed or printed on paper using an OCR font. The text, which is to be scanned is illuminated by a
low-frequency light source. The dark areas on the text absorb the light while light areas reflect it.
The photocells of OCR device receive this reflected light and provide binary data corresponding to
dark and light areas. OCR devices are used for large volume applications like reading of passenger
tickets, computer printed bills of credit card companies and reading of ZIP codes in postal services.
Bar Code Reader
Bar Code Reader is an optical scanner used for reading bar-coded data (data in form of light and
dark lines) as shown in Figure 5.14. The bar-coded data consists of a number of bars of varying
thickness and spacing between them. The bar code reader reads the bar coded data and converts it
into electrical pulses, which are then processed by computer. Bar-coded data is generally used in
labeling goods, numbering the books or encoding ID or A/c numbers.

Figure 5.14: A Bar Code Reader

Bar Code
Bar Code Reader

1462310916150290187372

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