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Information and Communication Technology Applications

to a file on disk. Although most new scanners determine an image’s colour components in one step,
Notes you can think of a scanner using three steps. The image’s colour components are determined by
reflecting red, green and blue lights from the image. The image’s red, green, and blue components
are combined to build the composite image. You can also scan an image with various resolutions
depending upon the scanner used. The image is sharper when resolution is high, but the size of
image file becomes large.
Scanning of Text. A scanner can be used to scan the paper documents. The scanner creates an
electronic image of the document. So, a graphic file is created always whether you scan a picture or
a document. In order to create text from the scanned document, you need special software called
OCR (Optical Character Recognition) software. This software converts the image into text. This
converted text is never 100% accurate (because some character are not scanned correctly) and needs
to be edited using a word processor. The scanned paper documents can also be used with fax software
for sending electronic image to another user using a PC. As scanners are cheaper than fax machines,
most people prefer them for sending faxes.
Built-in Scanner. Now-a-days, some PCs have built-in photographic scanner within the system
unit. In such scanners, you can insert the photo or document into the scanner’s slot just like an ATM
machine.

Digital Camera
Digital Camera is a type of camera that records images in an electronic format, storing the images
either on a disk or on a special memory, called flash memory.
A digital camera uses a CCD (Charge-coupled Device) element to capture the image through the
lens when the photographer releases the shutter in the camera. The image captured by the camera
can be transferred to the PC in two ways, depending upon how the camera store them. If the camera
stores the images on the floppy disk, you can simply insert the floppy disk in your PC disk drive
and copy to the hard disk. If the camera stores the images in its flash memory (A small plastic
device having 8 to 32 MB memory), they are downloaded by the cable connected to your PCs serial
port using the software supplied with the camera.

As the electronic images captured by digital camera can be manipulated and processed
much like the image from a scanner, the digital camera is a popular input device of
multimedia computer.
Touch Screen
Some special VDU devices have touch sensitive screens. These screens are sensitive to human fingers
and act as tactile input devices. Using the touch screen, a user can point to a selection on the screen
instead of pressing keys as shown in Figure 5.8. Touch screen helps the user in getting the information
quickly. It is mainly used in hotels or airports to convey information to visitors.

Figure 5.8: Demonstration of Touch Screen

Touch
Screen
Hand
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