FW: What Is A Screen Reader?

 
-----Original Message-----
From: uvip@yahoogroups.com [mailto:uvip@yahoogroups.com] On Behalf Of
Will Pearson
Sent: Saturday, April 30, 2005 8:59 PM
To: ossrp-control@freelists.org; uvip@yahoogroups.com
Subject: What Is A Screen Reader?

Hi,

I thought I'd share my, rather academic, view of what a screen reader
is.  It offers a little glimmer into what screen readers could
potentially do, and some of the pitfalls that the current crop of screen
readers have fallen into.  All this is from the viewpoint of human
computer interaction, psychology and communications theory.

OK.  So, what is a screen reader?  Well, it's actually a lot more than
people often assume it is.  It's not just something that grabs the text
from the screen and reads it to you, well, at least it shouldn't be, it
is in fact the interface by which user and machine communicate semantic
meaning, relating to thoughts, concepts, actions and states.

So, how did I arrive at this view?  As some of you may know, I've been
researching into semantics and their role in software interfaces for a
while now.  During this time, it's become apparent that software
interfaces are just intended to communicate semantic meaning, but as
we're not capable of extr sensory perception and telepathy with the
computer, we need some way to indicate our thoughts, concepts, actions,
etc. to the computer, and vice versa.  The way this is visually done is
by placing elements on the screen, such as icons, buttons, etc. and
having their shape, colour, position on screen and relationships to one
another act as encoding channels by which the semantic meaning is
conveyed.  Users then just point to an object, conveying the semantics
of which element they would like to interact with, and either click it
or select an action to perform on it from a menu.  All this is just a
form of physical encoding of the semantic meaning between user and
machine and vice  versa.

So, as a screen reader is a replacement for the visual interface, it's
role is simply to act as an interface between user and machine and
convey the semantic meaning generated by the machine.  However, there's
a nasty twist, and that is that a screen reader has to get the semantic
meaning that it is to communicate to the user from somewhere.  As the
screen reader has no access to the internals of the machine, it's only
available source of semantics that the machine wishes to convey is the
visual interface, which uses encoding techniques such as colour, shape,
position and spatial relationship to convey it's semantics.  So, a
screen reader should really be about extracting the semantics from the
visual display and encoding them in a non-visual form suitable for a
blind user, and this is where current screen readers fall down.  To
maintain accurate and efficient communication with the user, all the
semantics that are conveyed visually need to be conveyed to the user.
This incl  udes things like spatial positioning and spatial
relationships between interface elements, things that are currently lost
to the user when they are using one of the current screen readers.  If
this were to happen, then the number of errors, and according
back-tracks and reissuing of commands that go along with errors, would
decrease, and screen reader users would be more efficient beasts.

I haven't gone into design specifics, as they're for another day, and
these can dramatically affect efficiency as well, but that's my thoughts
of what a screen reader should be doing.  In focusing on the semantics,
then it's likely that through the use of semantic translation access to
all those difficult accessibility problems could be increased.

Will

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Received on Monday, 2 May 2005 20:37:16 UTC