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Scanners
Shown here is a picture of a flatbed scanner.
Scanners were developed as a new way to input data into the
computer. The Charge-Coupled Device (CCD) was invented to convert light
into electric pulses. Optical scanners incorporate CCDs and a light source
to convert pictures into computer data. Scanners work generally the same,
despite the difference in shape and appearance. Each type of scanner has
its own unique advantages and disadvantages. The main types of scanners
are handheld, flatbed, and feed-scanners. Since each type "scans" the image
or document in slightly different ways, they will be grouped apart.
Here are the Scanners that will be discussed in this section:
Flatbed | Hand-held | Feed
Flatbed
Here is the inside top view of a flatbed scanner.
The flatbed scanner was the first scanner ever developed because
of its outright simplicity. It is composed of a large sheet of glass (the
flatbed), a motorized carriage, a light source, and a CCD. The item to
be scanned is placed facedown on a large sheet of glass, and the scanning
is started by the user’s signal. The signal tells the scanner to turn on
the light source and begin "reading the picture". The scanner does this
by moving the CCD using a motorized carriage. The CCD reads the image/document
a line at a time. Gradually, it sends the information back to the computer.
When the scanner is done with the cycle, it signals the scanning software
that it is complete, and the individual lines are compiled together as
one complete image. Flatbed scanners usually connect to the computer using
a SCSI connector. This is due to the enormous amount of data the scanner
requires to be transferred at high speeds.
Continue the tutorial with the rest of the scanner section, starting with
Hand-Held.
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All material and images on these pages are copyright Joseph,Ed. This page was developed for the Thinkquest1999
competition.
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