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Lecture on Input Devices

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Presentation on theme: "Lecture on Input Devices"— Presentation transcript:

1 Lecture on Input Devices www.AssignmentPoint.com

2 Topics Keyboard OCR Mouse Scanner or digitizer Touch screen
Video digitizer Light pen MICR Joysticks Digital camera Trackball Voice or Speech input system Bar code reader OMR

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16 Uses for which OCR is Suitable
OCR is used in billing (e.g. gas and electricity bills, insurance premium renewals) and giro-forms. Billing often involves a turn-around document. For example, electricity bills are prepared in OC by the computer, sent out to customers who return them with payment checques. The documents are then re-entered via the OC reader into the computer system as evidence of payment. Note that no transcription is needed.

17 Advantages of OCR Key-entry is eliminated and data is captured in machine-readable form at the earliest opportunity. This should increase throughput and reduce costs and input errors. Characters can be read by people. Document design is less complicated and cumbersome than for OMR forms. Printing for OCR must meet high standards, and this is expensive. OCR is economical only when a large number of documents are to be processed. Only certain types of printed or handwritten characters are recognized. Document readers are relatively expensive. Only certain fonts are acceptable. The reject rate depends on the quality of the document, e.g. smudges, damaged forms, torn forms, etc. A high standard of printing is needed. Hand-printed characters can cause high rejection rates. Document design must still follow a rigid format.

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19 Situations where OMR is used
The data to be input is simple; The volume of data is large enough to justify designing documents; Turn around documents are used; Preparation equipment would be expensive or impractical.

20 Some examples of uses for where OMR are suitable
Multiple-choice examinations, aptitude tests; Insurance premium collection; Market research questionnaires - consumer research; In supermarkets for stock reordering; Traffic surveys; Payroll data entry.

21 Advantages of OMR Sensitivity can be altered to allow for different surfaces and pencils and inks. Has a better recognition rate than OCR. Can be prepared where data originates, without machines. Errors are easily corrected.

22 Disadvantages of OMR Mark readers are relatively slow.
Verification of marked data is difficult. Document may be difficult to understand and fill in or impractical to design. The document reader will have to be reprogrammed for each new document design.

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24 Uses of bar codes On labels on shelves - used for stocktaking, e.g. in factory stores. Printed on shop goods - see supermarket example. In libraries - for book and borrower identification.

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26 Advantages The characters are easily recognizable to the human being.
There is high accuracy in reading the characters by the input device. The input devices are reasonable in cost. MICR coding is flexible since documents of varying sizes, thickness and widths can be used without hampering the processing capability of the reading or sorting equipment.

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29 Digital Camera A digital camera (or digicam) is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. Many compact digital still cameras can record sound and moving video as well as still photographs.

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