[asvs] The Concept & Development Road Map
- From: "Will Pearson" <will-pearson@xxxxxxxxxxxxx>
- To: <asvs@xxxxxxxxxxxxx>
- Date: Fri, 8 Oct 2004 19:18:59 +0100
Hi'
Below, I've outlined the concept for the auditory synthetic vision system, as
it stands at the moment. I'm intending to use user centered design to make the
software fit to the user, not the user fit to the software. Due to this
approach, the concept may change, but whatever changes are made will result in
it being a better system for it's intended users.
I've also given a very brief development road map. This outlines the key
stages in the development of the system. Each one is based around a different
use for synthetic vision, and each will have testing involved with it, although
some stages may require no additional development from that associated with the
proceeding stage.
* The concept
Most people consider that we view shapes, as whole shapes. This is in fact not
the case, and we view little pixels of light, arranged in a grid, similar to
that on which computer and television visual output is based. It is then our
brains, that perceive these shapes as shapes, through a series of rules, to
which we then cognitively associate name and meaning.
Sound comes from all around us. We can perceive sounds from the front, the
rear, up, down, and all other directions. So, it is quite conceivable that we
can take advantage of this spatial ability of hearing to replicate the spatial
and parallel abilities of sight
The proposed auditory synthetic vision system would use a grid of sound pixels,
In doing so, this would closely approximate the spatial nature of sight. This
spatiality is an important aspect of the system. If semantics are considered,
then spatial relationships are one important form of conveying meaning. An
object may take on an entirely different meaning if it is located above another
object, than if it is below it, and by having a parallel, spatially positioned
display, spatial relationships between shapes and points within a shape can be
determined, thus conveying the encoded meaning to the user.
Auditory definition is poor in comparison to visual definition. Whilst
visually we can determine the position of something to a fraction of a degree,
auditorially, we can only determine it's position to approximately a degree.
This results in the loss of fine definition, and a more coarse display. This
is paralleled in low vision, where the long standing solution is to magnify
something to perceive the fine detail. This has the potential to work equally
as well auditorially, and so a system of magnifying a portion of the display
will be a core component of the auditory synthetic vision system.
To convey color, a mapping between color and the pitch of the sound at that
pixel's location will be made. Therefore, different sounds will be used to
convey different colors, with dark colors being represented by low frequency
sounds, and bright colors by high frequency sounds. This distinction between
colors is important, as by grouping colors of the same frequency together, it
abides by the Gestalt laws of similarity and proximity, and will help to
perceive shapes. Equally, differentiating between groups of one color, and
groups of another color will aid determination of shapes, again utilising the
Gestalt law of similarity. Should all the pixels forming a shape move at once,
then according to the Gestalt law of common fete, this system should be able to
allow a user to perceive motion.
So far, one piece of contextual design has been incorperated into the concept,
that is the ability to move the display. Having sounds emitted from a
direction, will effectively block sounds that also come from that direction.
This may be undesirable if the user is in a meeting, a student in a lecture
room viewing a set of slides, but who also wishes to hear the lecturer at
times, and many other contexts. Therefore, the ability to position the
displayed grid in a position of the user's choosing will aid in the usability
and usefulness of the system.
* Proposed Goals
The proposed goals of this system are simple and two fold. Firstly, there is
the research aspect, exploring whether this approach to auditory synthetic
vision actually works in reality, and if it does, then what the limitations
are. The second goal is to deliver a piece of access technology that is
affordable by, useful to and meets the needs of, the blind community.
* Key Stages In Development
1. Creation of a basic system to determine whether the concept works for still
images.
2. Determination of the system's ability to deal with moving images.
3. Testing as an actual "synthetic eye" using input from a web cam.
4. Evaluating the potential for a PDA version to increase system mobility.
If anyone has anything to add, then please feel free to contribute.
Thanks,
Will
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