[nfb-talk] Optacon:

helene ryles dreamavdb at googlemail.com
Tue Mar 3 21:06:32 UTC 2009

I hope the opticon does go back into ciculation. I learnt how to use
an opticon and I do miss the fact that it is no longer in production.


On 03/03/2009, Kenneth Chrane <kenneth.chrane at verizon.net> wrote:
> This is something we might do well to support.
> Jim Bliss
> New Optacon Design Ideas
> *by James C. Bliss*
> *1/26/09*
> * *
>             The Optacon was designed in the late sixties at the dawn of
> integrated circuits, silicon photocell arrays, and before microprocessors.
> The
> design was based on extensive experiments with human subjects, blind and
> sighted, that used computer simulation of various designs to determine the
> most effective for reading text.
> The final design incorporated a novel array of tactile stimulators composed
> of piezoelectric reeds, or bimorphs, a custom integrated array of silicon
> photocells, and custom integrated circuits of shift register/bimorph
> drivers.
>             The custom integrated circuits and unique piezoelectric reeds,
> together with the small market, made the Optacon a difficult product to
> source parts and manufacture.  However, for those that mastered its use, the
> Optacon filled an essential need.  Even though the Optacon has been out of
> production for over fifteen years, there are still over 150 avid users
> trying to maintain their Optacons and demanding a new Optacon.
>             Now, almost 40 years after the original Optacon design, advances
> in technology make possible a new Optacon design that could have greater
> resolution, be easier to learn and use, and could have features that would
> greatly extend the applications of use.
>             To reach the widest possible market, it is important to keep the
> simplicity of the original Optacon while enabling new capabilities and
> applications.  Below are my thoughts on design possibilities that could be
> considered.  Not all of these ideas may be worth developing, but considering
> them to assign priorities could help the process toward a new Optacon.
> I.  Resolution and Field of View
>             The original Optacon was designed around an array of 24 rows and
> 6 columns of pixels that drove a corresponding array of 24 rows and 6
> columns of bimorph tactile stimulators.   The 24 by 6 was based on tests
> with human subjects that indicated this was the minimum number of pixels for
> reading and tracking text at a practical speed.  Actually, if you consider
> 24 pixels across a 0.1 inch letterspace, this is equivalent to only 240
> dots/inch compared to the 300 dots/inch typically considered to be the
> minimum needed for OCR.  Also, the Optacon's 24 pixels across a 0.1 inch
> letterspace is equivalent to a visual resolution of only 20/40.
>             In addition, reading with an Optacon requires the user to move
> the hand held camera along a line of text.  The limited field of view of the
> Optacon camera requires this scan to be very precise; else the images of the
> text are cut off.  So reading would be easier and faster if the field of
> view of a new design could be greater, thereby relaxing the precision needed
> for line tracking.
>             Thus, for ease of tracking and reading a wider range of text
> fonts and text quality, more pixels would certainly be better, analogous to
> the greatly enhanced picture quality resulting from the recent television
> change from a 480 line interlaced scan to a 1080 progressive line scan.
>             Fortunately, advances in technology make an improved resolution
> and field of view possible at a reasonable cost.  Therefore, I believe that
> a goal of basing a new design on 36 vertical pixels to provide both improved
> resolution and greater field of view should be considered.
>             Unfortunately, the Optacon II, which was designed by Canon, had
> only a 20 by 5 array.  This reduction in resolution and field of view was
> one of the reasons reading is more difficult with it.
>             In the original Optacon design, the pixels were not square, but
> rectangles that were twice as wide as they were high.  This is because when
> camera is moved along a horizontal line of text the letterspace is sampled
> in the vertical direction, but an analog signal is obtained horizontally
> across the letterspace.  All of the image information can be obtained from
> one column of pixels moved horizontally across the letterspace.  However,
> tests with human subjects clearly showed that reading accuracy increased as
> more columns were added.
>             Based on these considerations, I suggest that a new design have
> 12 columns across the same horizontal field of view as the original Optacon.
> Thus, the newly designed Optacon's pixels would be square, with the vertical
> and horizontal resolutions being the same.  The 36 by 12 array would
> increase the number of pixels to 432, compared to the 144 in the original
> Optacon, perhaps justifying a name for the new model as "Optacon HD" for
> "high definition".
> II.  Tactile Array
>             In the past 40 years, there have been some significant advances
> in piezoelectric materials.  Several years
> ago there was a study at Stanford University that indicated the bimorph
> reeds in the Optacon tactile array could be half as long as in the original
> design.  This would allow incorporating the increased number of bimorphs in
> approximately the same space as before.
>             A complaint about the Optacon has been the noise that it makes.
> This noise comes from the bimorphs, which are being driven by a 250Hz square
> wave, a frequency of maximum tactile sensitivity.  This provides a strong
> tactile sensation.  The bimorph reeds were designed to be at near resonance
> at this frequency to consume a minimum amount of power from the battery.
> After
> the Optacon design was finalized and production had begun, we discovered
> this noise was greatly reduced if the bimorphs are driven with a 250Hz sine
> wave instead of a square wave.  This is because the human ear is much more
> sensitive to the harmonics of a square wave than to the fundamental 250 Hz
> frequency.  However, we never had the opportunity to test whether there was
> any detrimental effect on the tactile sensation when a sine wave drive is
> used instead of a square wave.  In a new design this should be tested and
> the sine wave used if desirable.
>             At Telesensory the assembly of the tactile array was labor
> intensive requiring considerable skill.  Modern manufacturing techniques
> including robotics could help reduce this cost.
> III.  Retina Module
>             When the Optacon was designed, no suitable integrated solid
> state arrays of photocells were available, so a custom design was developed
> in the Stanford Laboratories. Finding and maintaining sources for this
> custom part at the relatively low quantities needed made Optacon production
> difficult and expensive.  Now integrated solid state arrays of photocells
> are widely used in digital cameras, web cams, cell phones, etc.  Thus in a
> new design, a standard off-the-shelf part should be used if at all possible.
> IV.  Lens Modules
>             The original Optacon lens is not a true zoom lens because only
> the lens is moved to change the magnification.  This meant that the image is
> only in true focus at two points along the zoom range and out of focus at
> the ends and middle of the zoom range.  The amount of out of focus is
> sufficiently small to not be a problem given the low resolution of the
> original Optacon retina.  Because of the increased resolution I'm suggesting
> in a new design, a better zoom system will be required.  Actually, one of
> the Optacon prototypes built at SRI and Stanford did have a zoom system that
> moved both the lens and the retina to keep the image in true focus.  This
> did not change the size of the camera and would not be a significant
> increase in cost after tooling for production.
>             Various lens modules, such as the typing attachment and CRT
> screen module, were very important for the Optacon market because they
> increased employment applications.  While these particular accessory lens
> modules are not as important today, others could be developed for producing
> handwriting, reading LCD screens, viewing and taking pictures at a distance,
> etc.
>             In addition to image signals from the Optacon camera, an
> independent signal indicating camera movement should be considered.  While
> sometimes this can be derived from the camera images, there may be
> situations in which it may be desirable to have signals from the lens module
> rollers.
> V.  Electronics
>             Since the original Optacon was designed before microprocessors,
> the electronics did not include a microprocessor, however Optacon II did and
> any future designs most certainly would.  In addition, a new design could
> include some image storage as well as a port for an external memory
> stick.  This
> would enable camera scans to be stored for later retrieval and/or further
> processing on a PC.
>             OCR and synthetic speech capability could be built into the
> Optacon electronics.  These capabilities, together with the storage
> capability, means that the new design would need to have file handling and
> other software built-in.
>             A very important control on an Optacon is the threshold, which
> determines the photocell signal level between black and white.  Especially
> for poor quality print and for different colored print, how the threshold is
> set can determine whether the text is readable or not.  For precision
> threshold setting, I think this part of the circuitry should be analog with
> a high resolution potentiometer.  Unfortunately, in Optacon II this control
> was digital with too few bits for precision.
>             In addition to threshold and tactile stimulator intensity, there
> would need to be some additional controls, or buttons, similar to those on a
> "point and shoot" digital camera, for deleting images from storage, cycling
> through a menu, etc.
> VI.  Ports
>             A new design could have a port for the camera (possibly
> wireless), a port for power (batteries could be charged in the Optacon or on
> a separate charging station), a port for a memory stick, and a USB port for
> sending camera images to a PC, for enabling the PC to write on the tactile
> array, and for enabling new software to be installed in the Optacon.
> VII.  Battery
>             The Optacon II design was an improvement in battery convenience
> over the original Optacon and a new Optacon design could improve things
> further.  A system with readily available batteries that the user could
> easily replace and charge should be the goal.
> VIII.  Packaging
>             The Optacon II design was an improvement in packaging over the
> original Optacon and a new Optacon design could improve things further.
> IX.  PC Software for the Optacon
>             By providing a new Optacon with a USB port where camera images
> can be transferred to a PC and the PC can write tactile images on the
> Optacon means that the basic simplicity of the Optacon can be maintained
> while providing the possibility of adding many new features for expanding
> Optacon use.  Some examples are:
>             A.  Optacon Reading Lessons and Speed Building
>             Optacon training was essential in producing so many people that
> were successful in Optacon use.  Teaching someone to use an Optacon
> effectively was a labor intensive process.  The most successful Optacon
> training programs involved one teacher full time for every student for
> several weeks.  Since the seventies when these programs started, labor costs
> have dramatically increased relative to the cost of technology.
>             However, with the widespread availability and increased
> capability of PCs, it is now feasible to develop software that could
> automate at least part of the training process.  The PC could write letters,
> words, and text on the Optacon tactile screen, build speed by presenting
> these at various rates, test student progress, and provide feedback through
> synthetic speech.
> B.  Speech and Braille Output
>             By OCR processing the images from scans from the Optacon camera,
> the PC could provide speech or Braille output.  Several tactile stimulators
> could be combined to simulate a Braille dot on the Optacon's tactile screen.
> Speech and Braille files could be stored in the PC in addition to image
> files.
> C.  Optacon Screen Reader Software
>             Optacon screen reader software could be developed in which
> images from the PC screen were displayed on the Optacon tactile array.  The
> PC mouse could be used to move the field of view of the tactile image around
> on the screen.  This could be particularly useful in understanding screen
> layout, viewing graphics on the screen, and in formatting documents.
> X.  Conclusion
>             I believe that developing and disseminating a new Optacon along
> the lines described here would significantly enhance the educational and
> vocational opportunities, as well a personal independence, of blind people
> around the world.  I've described a design that would preserve the basic
> simplicity of the original Optacon, greatly improve the quality of the
> tactile image, and make tracking along a line of text easier.  By adding the
> capabilities of memory storage and communication with a PC, new features
> could be developed to make reading easier and faster through speech and
> Braille, and that would expand Optacon applications.  These design ideas
> need to be evaluated by the blindness community.
>             My guess is that the development of this basic Optacon alone
> could cost several million dollars.  (The PC software and other accessories
> could be developed later by third parties.)  However, the relatively small
> market coupled with the cost of development and the difficulties of selling
> to this market will discourage private companies from taking on such a
> project.  The situation is analogous to that with low incidence diseases
> where biopharmaceutical companies don't develop treatments unless there is
> some consideration such as "orphan drug status".
>             The hope for bringing back a new Optacon might rest on obtaining
> grant support for development and dissemination from private foundations or
> government.  For this to be viable would require strong support from the
> blindness community and leadership from an organization with the capability
> of accomplishing the task.
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