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From: hlab@milton.u.washington.edu (Human Int. Technology Lab)
Newsgroups: sci.virtual-worlds
Subject: Re: Many-dimensional input devices
Message-ID: <8127@milton.u.washington.edu>
Date: 25 Sep 90 17:42:57 GMT
References: <7985@milton.u.washington.edu>
Organization: Tektronix Inc.
Lines: 67
Approved: hitl@hardy.u.washington.edu



In article <7985@milton.u.washington.edu> cphoenix@csli.Stanford.EDU (Chris Phoe
nix) writes:
>... 
> 
> But input devices have a limited number of degrees of freedom, so they can
> only specify a few dimensions at a time.  What kind of transformation could 
> you apply to, say, a dataglove to allow specification of coordinates in 
> arbitrarily large dimensions?  Perhaps you could use one DF to specify which
> dimensions the others controlled.  As you bend your finger, different parts 
> of the building you're designing become highlighted, and then moving your
> hand changes their parameters.  However, this seems clumsy and it still won't
> let you change many dimensions at a time.
> ... [more suggestions on input techniques deleted] ...
> 
> Does anyone else have any suggestions for ways to build such input devices,
> either hardware or software?
> 

I think we have the same problem here which the dicussion on navigation ran
into awhile back: trying to map a many-dimensional, possibly highly
symbolic domain onto a few degrees of freedom which are easily mapped to a
space which human perceptions can make sense of (pun intended).  The idea
behind VR is to take adavntage of the many megayears of evolution which
have tuned human motor-sensory systems to their environment by simulating
the kinds of space (both physical and kinesthetic) found in that
environment.  But how to map a problem containing hundreds or thousands of
degress of freedom to the dozen or two that you can get from datagloves or
a datasuit?  Oh, you can add some degrees of freedom with gaze detectors
and such , but you still come up short.

So, let's cheat.  In normal conversation with other people, we don't use
just one sensory mode (if we did, we wouldn't need smileys in electronic
conversation to disambiguate what would normally be made clear by voice
tone or gesture).  Conversation with computers can be multi-modal too, e.g.
the voice, gaze, and gesture systems developed at the Architecture Machine
Group (the forerunner of the Media Lab at MIT).  Symbolic input, whether
via voice or gesture (like picking an item from a menu) can be used to
drastically reduce the number of degrees of freedom required *at any one
instant* to specify the user's requests.

Consider gestures: not static positions, but time sequences of
position/flexure data for joints.  Gesture detection software can add a
syntactic layer on top of the normal lexical interpretation of body
language (also intended).  Many more degrees of freedom exist now; a given
finger position, for instance, can be a part of many gestures, just as a
given letter can be a part of many words.  Better still, humans can learn
gestures and sequence of gestures quickly and reliably, probably better
than they can individual positions (try holding *any* position accurately
for any length of time).

Consider voice: a primarily symbolic input technique which can be used
(among many other things) to select the mode of input to be used by other
input techniques ("Print the document I'm pointing at"), to select the
range of valid values of another input ("Print the second and third
documents in the stack I've just picked up") and to manipulate the current
reality to reduce the number of degrees of freedom required for further
interaction ("Bring all documents tagged "R" in green to the front where I
can see them.").

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Bruce Cohen, Computer Research Lab        email: brucec@tekcrl.labs.tek.com
Tektronix Laboratories, Tektronix, Inc.                phone: (503)627-5241
M/S 50-662, P.O. Box 500, Beaverton, OR  97077