Computer Graphics

Topic : Input DevicesInput Devices

Light Pen

Voice System

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Definition

An input device that uses a light-sensitive

detector to select objects on a display screen.

Wired to a video terminal used to draw

pictures or select menu options.

It allows the user to point to displayed objects,

or draw on the screen.

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UsesCan be used on a computer screen, TV

screen and a smart board.

A light pen is similar to a mouse.

Construction

It includes a light that is detected by the pixels

on the screen.

It has a photoreceptor for sensing the signal.

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FaultShort lifespan.

Being easily damaged.

Works only with any CRT-based display , but

not with LCD screens.

When pointed at the screen, part of the

screen image will be covered by the hand and

pen.

Too much light can confuse the sensor, cause

it to operate differently. 5

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Application

Voice Command

Speech Recognizer

Dragon

Podcast

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VOICE COMMAND

It is a device controlled by means of the human voice.

By removing the need of using buttons, dials and

switches, users can easily operate appliances while doing

other tasks . Speech recognition converts spoken words

to text. 8

Speech Recognizer

It is commonly used in Graphic Workstations.

Commands are given through Microphones mounted on Headsets.

When a voice command is given, the system searches the dictionary for a match.

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Fault

• The speaker must have great voice clarity.

• Words may changed.

• Requires paid software.

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Questions…

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By, Akshay Kumar M S

BCA’1412