THE
FLATBED
SCANNER
The flatbed scanner is one of the most popular
scanners used, although other types are available. Scanners
are
used to capture graphic, photographic, and textual data for the
computer, without converting it in to machine readable data.
Other types of scanners are; the sheet fed scanner, hand scanners, film
scanners, barcode scanners, and others.
In order to select a scanner it is important to
understand your needs and usage. How often will you use the scanner,
once a day, once a week or a hundred times a day? What will you be
scanning, photographs, graphics, text, books, or 3 dimensional items?
Where will you be using the scanner, at home, in the office, while
traveling? All of these considerations become part of the selection
process.
The two most common image sensors that scanners use are
CCD (Charge
Coupled Device) and
the
CIS (Contact Image Sensor). CIS is a recent development
targeting entry-level consumer scanners. CIS-based scanners
are smaller, less costly and consume less power than the CCD based
units, but the trade off is they produce slightly lower-quality images.
The scanner resolution is measured in dots per
inch (dpi) and gives a representation of the quality of the
image captured. While 300 dpi is adequate
for average document scanning, 600 dpi provides
better quality results for
document and photo scanning. 1200 dpi or higher is
required only for highly demanding graphics work and photo scanning and
3200 dpi or
higher for film and slides. Of course the higher the resolution, the
more you will pay.
The color bit depth tells us how much color
information can be stored per pixel. It is measured in bits per pixel
or just bits. You will find the higher the bit depth, the better the
quality of the image. A 24 bit scanner provides good results for most
users, 36 bits is better for quality work. 48 bits or higher is
required for photographers and graphic artists. When you use higher bit
depths you create larger files.
The flatbed
scanner is good for general purpose use because it is
relatively inexpensive and performs most of the functions of all the
others. It can be used for scanning books and 3 dimensional items, as
well as text, photographs and graphics. This scanner is well suited for
the home or office, but does not travel well. The resolution can be as
good as needed, but this increases its cost. At the higher resolutions
this is ideal for the professional photographer and graphic
artists. Most flatbed
scanners require a transparency adapter to scan slides, film, x-rays
and other transparent
originals.
The sheet
fed scanner has an automatic sheet feeder and can
be loaded with multiple sheets of paper,
text, photos, and graphics; usually a standard size, 8 1/2 by 11, or 8
1/2 by 14. This scanner can not be used on anything thicker than a
sheet of paper or card stock. You will find it in many offices
where high volume scanning is required.
The hand
scanner is ideal for traveling; it is light
weight and can input documents into the computer. It scans one document
at a
time.
The film
scanner is just for transparencies, usually 35mm slides,
although other size film scanners can be found. This is used by a
photographer or graphic artist who has a large number of
slides or
35mm film to prepare for publication.
The barcode
scanner is used to input barcode data into the computer in
machine readable form. The scanner is either hand held or permanently
fixed while items pass in front of it. These devices are primarily
used in commercial applications.
Virtually all scanning devices interface with the
host computer using a USB (Universal Serial Bus) connector. Some of
the older scanners use a SCSI (Small Computer System Interface)
connection. For these devices a SCSI adapter card is required to
connect to the computer.
Armed with the information supplied here go to
your favorite online computer supply house and look at the scanners and flatbed scanners, availability.
Select the one that will satisfy your
needs and fits within
your budget.
If you would like to comment, or add any
information to
this page, please do so. Use the Contact
Us form and we will respond as
quickly as possible. If you would like to ask any questions, use the Questions and Answers
form and an answer will be provided.
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