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From: mortent@ifi.uio.no (Morten Tollefsen)
Newsgroups: misc.handicap
Subject: Re: Tactile Diagrams from Print?
Message-ID: <15263@handicap.news>
Date: 1 May 91 03:28:16 GMT
References: <15218@handicap.news>
Sender: wtm@bunker.isc-br.com
Reply-To: mortent@ifi.uio.no (Morten Tollefsen)
Organization: Dept. of Informatics, University of Oslo, Norway
Lines: 72
Approved: wtm@hnews.fidonet.org
Fidonet: Blink Talk Conference

Index Number: 15263

In article <15218@handicap.news> reinoud@duteca.uucp (Reinoud Lamberts) writes:

> Index Number: 15218
> 
> Some time ago I discovered that some copiers and laser printers
> produce output with distinctly perceptible edges on the
> boundaries between black and white parts. A blind girl, with a
> much keener sense of touch than I have, confirmed that she could
> interpret some ordinary laser-printed images.
> 
> The most interesting results were obtained with images processed
> by computer. A portrait processed with a high quality edge
> detection filter she readily recognized as such, and she could
> even detect that the portrait was of a woman.
> 
> On the techical part: to get perceptible edges a rather thick
> layer of toner is required. Therefore best results can be
> expected with cheap copiers and laser printers. Maybe it is
> possible to adjust the toner thickness on a device dedicated to
> tactile output.
> 

This is interesting!
Tactile images is a big problem because computers use graphic presentation.
Tecnically it isn't very difficult to design a tactile graphic tablet (this
is done for example in Germany). The problem is that blind people have not
the visual background to understand graphic in the same way as sighted
people.

Other problems with tactile images includes: how to represent different
colors, orientation, etc.. Braille printers can be used to print black and
white pictures (in USA the Versapoint printer from TSI has this feature).
Other Braille printers which can print graphics includes: Braillo (a
Norwegian printer) and Index Basic.

You said that a blind girl could interpret an ordinary laser output. I think
she is the exeption rather than the roule. Problems with tactile
interpretation is described for example by Gunnar Jansson, and his work is
very interesting.

I have don an experiment with tactile images, but this experiment is only
described in Norwegian. An overview follows:

6 simple symbols were printed on a Versapoint. The symbols were:
a horse shoe    (10)
smiling face    (6)
foot prints     (2)
wheelshair symbol (3)
don't enter sign (0)
traffic light (2)

The digits represent how many of the persons who was able to understand the
tactile image (10 persons were tested). In my article I try to explain this
results, but research is needed to find out: how to make graphics availiable
to visually impaired persons. This problem is getting increasingly importaint
because of the computer graphics, and I think that we have to use more
graphics in scools (as early as possible).

The problem is discussed in a lot of papers. I have some of them, and if it's
interesting I will send a list. I'm also very interested in articles
discussing tactile graphics, so if it's somebody who have something please
give me a reference!

I'm sorry for my poor English, but I hope it's understandable.
*M-T*
Morten Tollefsen
UNIK
Pb 70,
2007 Kjeller
Norway