Flatbed Scanner
Flatbed scanners contains following components:
- It has an optical system contains light beam and a lens and mirror.
- It has CCD (Charge Coupled Device),which allows to sense light and gives output.
- An electronic circuit which converts into bits so the computer can understand.
You all know when we take Xerox we see a flat glass that is called scan line.
When light is reflected, CCD gathers the information.
If the light is not sensed then it is stored as 0s.
If the light is reflected it will be stored as 1s.
In most of the scanners it has 300CCDs arranged horizontally which will give 300 bits.
It usually takes 5 to 20 seconds to scan to scan a full page.
Each reflected light beam taken by CCD is called picture element also called as pixel.
Pixel is also called as pel .
Scanners with 300CCD scans 180,000 pixel per square inch.
Each and every pixel will be in the form of 0s and 1s.
In computer the number of bits stored will be (7*300*9*600)bits =11.34,
in megabits=1.4175 MB.
The scanned version of text is is known as bit map.
If the paper is plain then it will be stored in ASCII form.
For example: 80 characters per line, 24 lines per page, number of character in page is 1920.
Then, the ASCII form is 1920bytes.
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