Tuesday, September 04, 2007

Devices to Assist Students with Visual Impairments

Closed-Circuit Television Magnification (CCTV):
CCTV is designed to enlarge
any type of text or graphic material by using a small vertically mounted
video camera with a zoom lens directly connected to a monitor for display-
ing the image. The text or graphic material is placed under the camera lens
on a sliding reading stand and the image is projected on the attached video
monitor. CCTVs allow the user to adjust the magnification, contrast,
brightness, and focus, and to change the background display to either
black or white, or in some cases, color. Older CCTVs, while still useful for
many classroom applications, are expensive and cumbersome to move. But
the newer, smaller versions of this technology are portable, and thus much
easier for students to use.

Computer Screen Magnification:
Most computers sold today allow for the
magnification of the screen through the use of special software. Typically,
the user can select a portion of the screen and then enlarge that section up
to 16 times the original size. Although the user is somewhat inconve-
nienced by having to view a smaller portion of the original screen as the
magnification increases, this technology makes it possible for students with
visual impairments to use computers in ways similar to their nondisabled

Descriptive Video Services (DVS):
DVS technology inserts a narrative verbal
description of visual elements—such as sets and costumes, characters’ phys-
icaldescriptions, and facial expressions—into pauses in a program’s dialogue.
The majority of television sets and VCRs manufactured in the past six years
have been designed with a “second audio program” (or SAP) switch that
can be turned on so that the user can automatically hear descriptive video.
DVS is available for both standard VHS and DVS formatted videotapes.
DVS technologies help students by providing them with access to informa-
tion, and through the increased opportunities to discuss programs and
movies that are part of the popular culture, by providing them with oppor-
tunities for increased socialization and knowledge building.

Screen Readers:
Screen reader software represents what is known as a text-to-
speech application, which analyzes letters, words, and sentences and con-
verts them into synthetic or digital speech. Today, text-to-speech software is
common in many software packages, including many word processing and
educational software programs in math, reading, and spelling. In some
instances, the student can adjust the volume, pitch, and speed of reading, and
even choose between a male or a female voice. With synthetic speech, the
computer reads text passages, analyzes the phonetic structure of words, and
attempts to reconstruct the words by putting together a string of synthetic
phonemes that are then “spoken” by the computer. However, when the
words are not phonetically predictble, the results can be difficult to under-
stand. In contrast, digital speech is composed of actual recordings of human
speech. While digital speech is much easier to understand, it requires a large
amount of storage because each word that the computer may encounter
must be prerecorded. Consequently, its use is often not feasible for class-
roominstruction. As more low-cost options for storing electronic information
become available, however, this technology will likely be used more extensively
to assist students who have communication disorders or visual impairments.

Optical Character Recognition (OCR):
OCR technology enables blind stu-
dents to place books or other print materials on a scanner and have the text
interpreted and read using synthetic or digital speech. The first OCR
system for individuals with visual impairments was introduced in 1976,
when Ray Kurzweil invented the Kurzweil Reader. The early Kurzweil
Reader was about the size of a small photocopy machine and was consid-
ered to be a truly remarkable advance for students with visual disabilities.
While the device was often found in libraries, it was too bulky and expen-
sive to be available to students in the classroom. Today, there are portable
stand-alone OCR devices and devices that can attach to other computers
and scanners.

Braille Notetakers:
Braille notetakers are small, portable devices that enable
students to enter and store Braille characters in the form of words and sen-
tences. The notetakers use the same six keys found on a traditional Braille
writer used for making a paper copy of Braille. However, most notetakers
allow users to review what they have written by listening to the text-to-
speech function of the device. In addition, software translators allow the
Braille to be converted into text. The stored files can then be used with a
standard word processor or a screen reader. To get a hard copy of the infor-
mation that was entered, the user can connect the notetaker directly to a
standard printer for text output or a Braille printer for Braille output.
Similarly, a paperless Braille display can be attached to a computer or a per-
sonal notetaker that can display up to 80 characters simultaneously. Devices
such as the Braille notetaker that combine Braille with computer technol-
ogy have made Braille much more useful than it was in the past.


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