Scanners
“The Computer as an
Educational Tool:
Productivity and Problem Solving”
©Richard C. Forcier and Don E. Descy
Scanner Functions
 Graphics
and photos
 Digital files
 Data entry
Scanner Types
 Flatbeds
 Sheet-fed
 Film/Slide
 Handheld
 Portable
Flatbed Scanners
 General
purpose
 Multifunction
 Most common
 Affordable
Sheet-fed
 Document-management
 Office
scanners
 Compact
tasks
Film/Slide
 High
resolution
 Scans slides, films, negatives, and
transparencies
 Light is projected through the
original to the other side.
Handheld
 Works
well for awkward sizes
 Several passes over a regularsized document
 Scans can turn out uneven.
Portable
 Lightweight
and compact
 About the size of a bestseller book
 Image quality isn’t as good.
Scanner Features
 Resolution
 Bit
depth
 Dynamic range
 Software
Resolution
 How
many dots per inch (dpi) a
scanner can record
 Optical vs. interpolated resolution
 300 dpi is sufficient for most uses.
Bit Depth
 Amount
of information that the
scanner can remember about each
pixel
 The higher the bits, the more
details a scanner can record about
an image’s color or gray scale.
 For most home uses, a 12-bit
scanner is adequate.
Dynamic Range
 Similar
to bit depth
 Measures the ability of scanners to
reproduce tones
 Standard flatbeds typically have a
range of 2–2.5.
Software
 TWAIN
drivers allow a piece of
hardware to work with a computer
system.
 Different software caters to
different audiences.
 Research software according to
needs