Sight-to-Touch Translator
The tactile principle of Braille printing would be adapted to avoidance of
obstacles. 
NASA's Jet Propulsion Laboratory, Pasadena, CA
From:	NASA Tech Briefs - March, 1998 - page 56

The sight-to-touch translator (ST3) is a conceptual electronic apparatus that
would generate a tactile representation of visible objects in its vicinity.
The ST3 would be worn by a blind person; the tactile display would help the
wearer to visualize nearby obstacles and act to avoid them. Thus, the ST3
might serve as an electronic alternative to a guide dog under some
circumstances. 

The ST3 concept has become feasible in recent years, through advances in
miniaturized image-detecting electronic devices, processing of image data,
and microelectronics in general. The ST3 (see figure) would include a state-
of-the-art active-pixel sensor (APS) as its image detector. The output of the
APS would be digitized and fed to a minicomputer, wherein the image data
would be processed through edge- enhancement and gray-scale-based
clutter-detection algorithms. The computer output would comprise data on the
outlines of obstacles and other objects in front of the wearer. 

The outline data would command the generation of a tactile dot representation
of the outline of the object onto a rectangular electromechanical
tactile-display device that would look like a giant dot-matrix printing
mechanism. The tactile-display device would have dimensions of about 6 by 10
cm and would be mounted on the wearer's chest, forehead, or other convenient
sensitive skin area that would provide a direction reference. 

The ST3 would include a range finder similar to the range finders on
autofocus cameras. Inasmuch as only nearby objects would be of interest for
avoiding obstacles, the output of the range finder would be used to limit the
processing of image data to those parts of the scene that lie within a
distance of about 5 m. 

Alternatively or in addition to tactile dot representations of the outlines
of obstacles, the apparatus could generate standard tactile dot patterns,
analogous to Braille characters, to represent stairs, curbs, doorways,
vertical obstacles, and other common objects that the image- processing
software would recognize by correlation with previously acquired image data
stored in the computer memory. The apparatus could also be made to generate
audible signals based on the detection of specified colors in specified
configurations (e.g. from traffic lights and illuminated exit signs). 

This work was done by Philip I. Moynihan and Maurice L. Langevin of Caltech
for NASA's Jet Propulsion Laboratory. For further information, access the
Technical Support Package (TSP) free on-line at http://www.nasatech.com under
the Electronic Systems category. 

Figure caption:
The Sight-to-Touch Translator would translate the image of a nearby object
into a tactile dot representation, which would have characteristics of both
Braille and dot-matrix printing.