Page 572 - Ultimate Visual Dictionary (DK)

THE MODERN WORLD
Flatbed scanner

Power supply
cable
SCANNERS CONVERT physical SCANNER
images into electronic form,
Integrated
allowing them to be sent over the transparency Reflective
document
internet, displayed on a website, unit (TPU)
mat
stored on a computer, and
Glass plate
manipulated using specialized Direct TPU
software. Scanners work by current connector
Lock (DC) inlet port
detecting and analyzing light
Start Inverter
reflected from an opaque image, button and board
such as a photographic print. indicator
Some can also scan photographic light
Lamp
transparencies by analyzing light power
Photo
that has passed through the image. supply
print
Flatbed scanners contain a unit, button Scan to email Scan to connector
called the scan head, that contains button Web button
a lamp, mirrors, a lens, and an
FILM AND SLIDE HOLDER
array of CCDs (Charge-Coupled
Devices). The carriage passes
beneath the image; the lamp
shines light on to or through the
Shield
original; the mirrors reflect the plate
light on to the lens, which focuses
it on to the CCD array. Each CCD
detects the brightness of light 35mm- 35 mm film
from a particular pixel (picture slide strip
holder
element) along a· horizontal strip holder
and converts this data into an
electric signal. For color images,
the light is usually passed through
Panel
red, green, and blue filters and board
then directed to the CCD array connector
so that it can be broken down
into its component colors. This
information is then converted to
digital form. The quality of the
image depends on its resolution,
measured in dpi (Dots Per Inch).

HOW A FLATBED SCANNER WORKS
Lens focuses light on to CCD array
Glass plate
Original image
(photograph or The electronic image
artwork) is converted to digital
Lamp form and transmitted
to a computer

CCD array builds up electric charges that vary Cover support
according to the brightness of the light beam
Light beam is reflected
from the original to a Carriage is moved beneath the original by a
series of mirrors stepper motor in a rapid series of tiny steps

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