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Fw: Accessing Graphics

From: Will Pearson <will-pearson@tiscali.co.uk>
Date: Wed, 15 Dec 2004 15:14:57 -0000
Message-ID: <005801c4e2b8$da39d6e0$c58b6051@WillPearson>
To: <wai-xtech@w3.org>


----- Original Message ----- 
From: "Will Pearson" <will-pearson@tiscali.co.uk>
To: "Al Gilman" <Alfred.S.Gilman@IEEE.org>
Sent: Wednesday, December 15, 2004 2:49 PM
Subject: Re: Accessing Graphics


>
> ----- Original Message ----- 
> From: "Al Gilman" <Alfred.S.Gilman@IEEE.org>
> To: <wai-xtech@w3.org>
> Sent: Wednesday, December 08, 2004 3:59 PM
> Subject: Re: Accessing Graphics
>
>
> >
> > At 9:17 PM +0000 12/6/04, Will Pearson wrote:
> > >Hi;
> > >
> > >Diagrams are a prevalent form of communication in contemporary
> > >society.  They are used to explain task sequences, convey concepts,
> > >even design interactions between classes in a UML sequence diagram,
> > >yet they remain one of the last frontiers in the world of accessible
> > >information.  This need not necessarily be the case, as after all,
> > >diagrams are just a transport mechanism for meaning as much as the
> > >words on this page are.
> >
> > But diagrams are frequently used when the plot of the story to be
> > told does not follow a single, linear
> > thread or loop-free topic tree.
>
> I agree.  My comparison was just to illustrate the fact they both convey
> semantic meaning, but use different forms of encoding :-)
> >
> > So accessing a linear narrative, or a linear-plus-grouping
> > book-structured treatise does not give us all
> > the precedents we need to deal with access to diagrams.
> >
> > We are familiar with a variety of navigation modes from
> > book-structured documents:
> >
> > - serially through the whole thing in full detail
> >
> > - serially through action opportunities via tabbing
> >
> > - with seven league boots through titles of sub-topics of the current
> > topic as in the DAISY table of navigation
> >
> > - table navigation, up/down left/right inside a regular grid of
> > repetitive cells
> >
> > I think that in accessing diagrams we need to recognize that there
> > are arcs linking the objects in the scene. Some of the objects are
> > diagrammatically presented as connected or related, while other pairs
> > are not.
> >
> > So there is a new sub-function involved in what I call "graph
> > navigation" which is that there need to be facile means to discover
> > and navigate to the strongly related objects, based on the currently
> > focussed object.
>
> Yes.  Poehlman and myself have been discussing this recently.  Our latest
> thoughts went into the keyboard exploration scheme in the SVG 1.2
feedback.
> However, I'm not convinced this is the perfect method, as you're still
> trying to squeeze what is a parallel, spatially based, system of encoding
> through a linear, sequential channel.
> >
> >
> > >There's three main ways in which I consider diagrams can be made
> > >accessible.  Each involves extracting the meaning from it's
> > >diagramatical encoding, but each differ in where that decoding takes
> > >place.
> > >
> > >A bit of communications theory.
> > >There's various communications models used to explain how people
> > >communicate with one another and technical communications systems.
> > >One of these, which is classed as a transmission model of
> > >communication, is Claude Shannon's 1948 model that featured in the
> > >Bell Systems Journal of that year.  Shannon proposed that there were
> > >five stages to communication:
> > >1. A sender considers the meaning to be sent
> > >2. That meaning is encoded into some physical form
> > >3. The physical representation of the meaning is transmitted to a
> > >receiver, using physical communication channels
> > >4. The physical representation is decoded to expose the transmitted
> meaning
> > >5. The receiver then absorbs the transferred meaning
> >
> > This is fundamental.
> >
> > We have this cycle now more integrated in the WAI public messaging.
> > At least a toehold.  See
> >
> > http://www.w3.org/WAI/intro/components
> >
> > But we still have to follow through on this principle.
> >
> > In WCAG, for example, it has to be clear that the
> > author-through-server are responsible for delivering something that
> > enables the user's control of presentation through the application of
> > user-configurable transforms in the User Agent.
> >
> > >If we apply this to diagrams, the lines, colors, spatial
> > >relationships are purely encoding, and are distinct and separate
> > >from the meaning they convey.
> >
> > That's where I fall off the track. The use of 'purely.' Even in the
> > business to business world of electronic document interchange,
> > there's no purity to the encoding. And the encoding there is more
> > consistent, more strongly controlled, than in the bulk of the
> > X-to-consumer Web.
> >
> > The encoding is the relation or mapping between percepts and
> > concepts. The percepts are not pure anything. One perceives what one
> > conceptually expects. It's all part of a coupled, recursive process
> > whether on the speaker's side emitting the 'communication act' or on
> > the hearer's side building an estimate of what the speaker was
> > thinking.
> >
> > >Therefore, to get at the meaning, all that needs to be done is to
> > >decode the physical representation of that meaning.
> >
> > Once again, this exaggerates the precision of encoding in human
> > communication. Natural communication is full of what we call
> > allusion. You could call it fuzzy encoding.
> >
> > While on the one hand, I have been saying that we need to make the
> > cycle Will described above the backbone of our model of Web
> > communication, and present accessibility in that context, we still
> > need to go a step further to recognize that web content is
> > semi-formal. By this I mean that there are strict models for some
> > aspects of what is being conveyed, but not alll aspects.
> >
> > A key plot point is that in Web communication there is a transform
> > being done at the client side from the wire format to the physical
> > presentation (and event acceptance) form. It is in many cases easier
> > for the user to control this transformation being done at the client
> > side than to reach our and perturb what is being done on the server.
> > [But not always]
> >
> > >It's this decoding that causes problems in accessibility.
> > >Psychology examines the process of receiving meaning in a bit more
> > >detail.  According to psychology, we first receive sensory stimuli,
> > >which can be in the form of waves, particles or contact with other
> > >physical objects.  We then automatically group these into perceptual
> > >groups, which in the world of diagrams would be the lines, shapes,
> > >colors, words, etc. that form a diagram.  The final stage in this
> > >process is for us to cognitively associate meaning with those
> > >perceptual groups.
> >
> > When the application is mailing the baby's picture to a grandparent,
> > most of the message is in the image; the concept that this is their
> > grandchild is part, but the smaller part.
>
> I agree, but how do they determine it's their grandchild?  They would take
> all the pixels that they receive as sensory stimuli, the brain would then
> group them into perceptual groupings based on something like the Gestalt
> laws, they would then recognise it's a baby.  They would then
> > perform this for all the components of the image, realising the person
> holding the baby is their son or daughter, and then make the assumption
that
> it's their grandchild.  I say assumption, as unless they've been told
> otherwise there could be a number of reasons why their son or daughter is
> holding a baby.
>
> So, the meaning is conveyed through the spatial relationships between
> pixels, and at a more coarse granularity, the relationships between
objects
> in the image.
>
> > But in diagrams, the message is symbolic and we have lots of ways to
> > represent or interactively browse said message.
>
> Yes and no.  I think the same component operations are used for both
> diagrams and images, but we perform the operations sub-conciously with
> images.  We associate some meaning with a group of pixels within a given
> context, and we further enhance that meaning through other semantic
encoding
> channels such as color and spatial relationships.  For example, the baby
is
> being held by a person, and we know it's a picture illustrating someon'e's
> new born child.  Regardless of how many other babies are in the image, we
> know it's their baby as a result of the spatial relationship between the
> baby and the person.  This is true for diagrams, where you can gain
> additional meaning from the spatial relationships between diagram
elements.
> >
> > >Examining the psychological process of receiving information,
> > >there's two main problematic areas for accessibility.  Either people
> > >can't receive the sensory stimuli due to physical, environmental or
> > >other constraints, or they cannot cognitively associate meaning with
> > >the perceptual groupings, which may be due to one of a number of
> > >factors.
> >
> > FWIW my recounting of this tale is at
> >
> > http://trace.wisc
> .edu/docs/ud4grid/#_Toc495220368
> >
> > >Semantics can resolve both of these issues.  If it's embedded as
> > >part of the physical transportation medium, then the transferred
> > >meaning can be reassembled in any form suitable for the user.  This
> > >could be a form that bypasses problems, be they physical,
> > >environmental or whatever in nature, that prevent the user from
> > >receiving sensory stimuli, or it could be a form adapted to allow
> > >the user to cognitively associate meaning with the perceptual
> > >groups, where they may have been unable to with the original
> > >perceptual groupings.  Most people are familiar with the fact that
> > >some people cannot receive certain types of sensory stimuli, the
> > >blind cannot receive light waves, the deaf sound waves, and so on,
> > >or it may be in appropriate for people to receive certain types of
> > >stimuli, well, you need to look where you're going when walking, you
> > >may fall down some steps.  However, accessibility goes further than
> > >just dealing with issues of disability, be it permenant or physical,
> > >the ultimate aim of accessibility is to ensure everyone can access
> > >meaning.  This includes adapting the encoding of the physical
> > >representation, but not the type of stimuli used to encode it.  For
> > >example, a blue line would yield no meaning to someone unfamiliar
> > >with the UK's Ordenance Survey 1:50000 maps, yet it represents a
> > >motorway.  This is because they haven't learnt the particular set of
> > >symbolic encodings used in an OS 1:50000 sheet.  Through the use of
> > >semantic content adaptation barriers such as this lack of knowledge
> > >of various symbolic encoding sets can be overcome.
> > >
> > >Semantic content need not necessarily be encoded in the physically
> > >transported content, it can be gained after transportation.  The
> > >final stage of the psychology sequence involves associating
> > >cognitive meaning with sensory stimuli, or in other words,
> > >extracting the semantics from the content.  This process can be
> > >automated by intelligent agent software that have been taught the
> > >encoding techniques used in a particular diagramatical context, and
> > >this set of extracted semantics can then be reencoded as if the
> > >semantics were originally embedded within the transported physical
> > >representation.
> > >
> > >Finally, and to me the most fun, as I've been working on this in
> > >industry, is adaptation of the sensory stimuli itself.  This is only
> > >suitable for those unable to receive the sensory stimuli for
> > >whatever reason, and involves converting diagrams and images into a
> > >form of sensory stimuli that the intended receiver can receive.
> >
> > Try ... converting a web dialog containing diagrams into an alternate
> > dialog that communicates...
> >
> > A lot of what I have had to say about access to problematic
> > presentations, both transit timetables and tax-preparation
> > flowcharts, has focused on what is known in the trade as 'equivalent
> > facilitation.'  Using
> > interaction as a resource to eliminate the need for the presentation
> > of an acyclic graph as essential
> > to the task at hand.  Specifically, getting the user to input where
> > they want to go, and from where,
> > means that the server can present a short list of route plans each of
> > which is a linear story, rather than
> > a route map or a timetable that takes a lot of skill to navigate.
> > Also the flowchart was an inferior way
> > to explain the logical flow through the preparation of a tax form;
> > whereas activating the individual decision
> > questions with hyperlinks provided a superior explanation.  The
> > availablility of active navigation eliminated
> > the need for flowlines in the graphic.  The story unfolds through a
> > dialog rather than by reconstructing
> > it tracing a path through the diagram.
>
> I agree that this is a good way to display some content.  However, it only
> works when there's a clear sequence through the elements, and doesn't take
> into account jumping from one point to a random point, which the user may
> wish to do for various reasons, maybe context, maybe they've forgotten
> something.  It also fails to take into account document exploration.  A
flow
> chart will show all actions at the same stage in the process, therefore
the
> user can "look ahead" and determine what the consequences of taking a
> particular fork in the sequence would be.  Therefore, it aids in the
> decision making process, and this sort of decision making ability is not
> found in conventional wizard style dialogs.
> >
> > http://www.w3.org/WAI/RD/2004/06/28-agenda.html
> >
> > But this thread should be about access to the diagrams, with a brief
> > nod to the alternative dialogs for the
> > cases where the authoring side should go there first.
> >
> > We should review the Bulatov work, where it gets us and what needs to
> > be done next.
> >
> > http://www.svgopen.org/2004/papers/SVGOpen2004MakingGraphicsAccessible/
>
> There's also Rotard, M and Ertl, T, Tactile Access to Scalable Vector
> Graphics for People with Visual Impairment, In proceedings of SVG 2004,
> (abstract)
> http://www.svgopen.org/2004/paperAbstracts/TactileAccessToSVG.html
> >
> >There's also Grigori Evreinov's work on Spotti mapping.  Spotti, whilst
> intended to be a synthetic vision system, could be used for diagramatical
> access without some of the anatomical limitations of tactation.  Spott
paper
> at:
> http://www.acoustics.hut.fi/icad2001/proceedings/papers/evreinov.pdf
>
> Will
>
Received on Wednesday, 15 December 2004 15:12:47 GMT

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