People might be interested to read this message from Jim Bliss. The
old-timers among us will know who he is -- the rest will just have to
ask or wonder.
David Andrews
>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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