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*
> * *
> The Optacon was designed in the late sixties at the dawn of
> integrated circuits, silicon photocell arrays, and before microprocessors.
> 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
> 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.
> 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,
> 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
> 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
> 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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