| A
visual presenter is a color video camera mounted on a movable
arm that is positioned over a large base on which objects
can be placed. The base, called the stage, usually has side
and bottom lights to illuminate the objects such as books,
solid objects, or transparencies.
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The camera has a lens that lets the user obtain
an image of the entire object or it can zoom in for close
up views to see very small areas. For objects such as an insect
like a fly, the detailed body down to its individual hairs
can be seen. Or when viewing a printed picture from a magazine
the individual ink dots can be seen at a high zoom magnification.
The image produced by some visual presenters
is identical in electronic form to that of a VCR or DVD player
and thus can be seen using a TV, plasma panel, or a data/video
projector. The images can be used to study an object or can
be shared with a class or general audience.
Years ago, the only option available for this
type of viewing was a device called an opaque projector. The
projector was big and bulky, plus the image was not very bright.
It used many lamps with a large lens arrangement to allow
teachers to project images of solid objects or documents such
as text from a book.
The advent of bright and affordable data/video
projectors (which allow a camera, VCR, DVD, or computer screen
image to be projected to a group) marked the death knell of
the opaque projector.
Since a company called "Elmo" marketed
one of the early visual presenters (also called document cameras),
this name is often associated with the product, just as Frigidiare
is with refrigerator, or Kleenex is with facial tissues. However,
it is important to know that Elmo is a brand name. There are
dozens of manufacturers of visual presenters.
Visual presenters are now found in two different
general types: analog and digital. An analog visual presenter
uses a small video camera that produces NTSC video image format,
the same video signal that comes out of the back of a standard
VCR.
This means that the images coming from an
analog visual presenter can be input into a VCR, a function
few people are aware of, and thus few people take advantage
of this ability to record the visual presenter images on inexpensive
VHS tape.
Analog visual presenters, up until recently,
have been much more affordable than digital ones. With the
price of the CCD camera chips that capture images digitally
plummeting in price, along with inexpensive computer memory
and other microchip-based products, digital visual presenters
are now priced on an almost even level with analog visual
presenter.
Digital visual presenters use the same technology
as a hand held digital camera, and produce a computer compatible
signal.
Many digital visual presenters can plug directly
into a data/video projector using the data signal port. In
most cases the resolution of the image is 2 to 4 times better
than that of the normal TV image produced by an analog presenter.
Such a resolution increase is a major advantage
since with an XGA resolution of 1024 x 768, it is nearly possible
to image a full 8-1/2 by 11 inch sheet and read all the text.
This is also important when it is necessary to resolve the
detail on certain objects.
Some digital visual presenters can be connected
to a computer. Here the image obtained by the presenter is
sent to the computer, processed, and appears on the computer’s
monitor or a laptop’s LCD. This same image can also
be transmitted to a projector for display on a large screen.
Another advantage of the digital visual presenter
is that it will permit the capture of images in a computer
based digital format. A connected computer can then save a
file of the subject or item placed in the viewing area. The
digital visual presenter is, in a sense, a scanner, since
it can capture live images at high resolution to a computer
file.
Some digital visual presenters can even capture
and store many images internally without a computer. These
images can be later recalled and used to compare with live
images or for describing a process.
When combined with a computer, a rapid series
of images forming a short movie can also recorded.
Visual presenters come in versions that have
lights, typically fluorescent lights located on folding arms
that allow the users to provide more light on the object being
viewed. Some may not have any lights and depend on the ambient
room illumination, which vary greatly.
Finally, another option is the need to show
transparent media such as viewgraphs or 35 mm slides. Many
visual presenters have lights below the stage. This allows
transparencies that may have originally been created for an
overhead projector to be easily viewed. Some have special
holders for 35 mm slides and permit them to be viewed as a
full screen image.
In finding the best source to obtain your
visual presenter, you need to consider the same factors that
apply to other product categories. How does the warranty compare
to that offered by other manufacturers? How easy is it to
contact the tech support department. You also want to ascertain
whether you can contact tech support after the warranty period
has elapsed. Some companies are now charging for tech support
on out of warranty items.
Visual presenters offer an easy way to show
existing classroom materials. The resulting images can be
easily sent to a data/video projector and thus appear on a
large screen for all to see. Consequently, visual presenters
extend the usefulness of the investment you have made in a
data video presenter.
What are some ways a visual presenter can
be used in a Classroom?
• To show a picture or chart from a
textbook
• To share examples of student writing
• To show artifacts such as buttons,
fossils, seashells, plants
• To show live science experiments in
Biology or Physics classes
• An analog presenter can be set to
view an ant farm, then attach the presenter to a VCR, record
over time, and play back the construction of the ant tunnels
• A digital presenter can capture pictures
from a textbook that can then be imported into PowerPoint.
Overhead
projector | Overhead
projector explained | How
to buy an overhead projector |
Why
choose an LCD projector? | Choosing
the right projector for your meeting |
Choosing
a Visual Presenter
| Everything
about Overhead Projectors
| Digital
laser Projection
|
Keys
for Dynamic Public Speaking
|
