On the matter of the new Optacon (models A, B, C, and D versus
E):
Many folks think that the disadvantage of the new Optacon is that
it has fewer tactors (fewer vibrating pins. Nah!
Smith-Kettlewell experiments showed that you could greatly reduce
the resolution of the tactile display with little degradation in
performance.
The real advantage in models A through D was the "soft threshold"
inherent in the analog nature of detection of dark spots under
the camera. With the threshold control, the user could
"cheat" the system for thick lettering -- such as bold type --
and, by tollerating missing portions of the letters, reduce the
stimulous so as to increase the chances of picking out critical
detail (grapling with the lower-case e a s o confusion, for
example).
The model E has a hard threshold, brought to us by the magic of
digital detection of the camera's image. Either a dark spot
actuates a stimulator, or it does not. This alows no "fuzziness"
to be selected by the user to make thick print -- with
insignificant gaps in thick/bold presentation -- tactually
perceivable.
The model E is a much nicer package. The replaceable battery
takes away the most failure-prone component that made us send in
our classic units. Model E still works for some print styles,
and with this instrument, one can "bottle feed" a flat-bed
reading machine to get what =U:9QjU
I9j|
I don't know what to do about the demise of the Optacon, but I,
and Harvey Lauer at Hines VA, believe in "direct-translation
reading aids" as a tool, even if you have the latest scanner-type
things. As Lauer put it in 1978, "Some vehicles are built for
good smooth roads, and you should use those wherever possible.
However, on trails and rough terrain, a bicycle may work where
nothing else will do."
As we are confronted with graphic displays, some of which will
not allow us electronic access, "direct translation" reading aids
will always be with us, and we'll find ways to build them.
Bill Gerrey
bilge@skivs.ski.org
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