From: John Costella <jpc@physics.unimelb.EDU.AU>
Subject: Re: DESIGN: 3D computing vs. virtual reality
Date: Mon, 18 Dec 1995 11:04:00 +1100 (EETDT)


From: John Costella <jpc@physics.unimelb.EDU.AU>

> John Wann wrote:
> >
> >> There is no need to seperate tele-operation from computer-generated
> >> displays. Both are virtual in the optical sense. A virtual optic array
> >
> John Costella replied:
> >
> > it is natural that you use "virtual" in its optical sense. But I do not
> > believe that this is generally relevant for "virtual world" or "virtual
> > reality".

John Wann replied:
> 
> [details omitted]
> These are not "OPTICAL" criteria but "PERCEPTUAL" criteria - the essence of
> what is or is not VR is the perceiver - if you perceive "virtual depth"
> then the system has to be a VE

This is a better definition of the concept you describe, but I would
call it "presence" (or rather "visual presence"; let's not forget the
other senses), rather than being of necessity a "virtual world".
Telepresence indeed gives you this experience.

The problem I have with calling telepresence in itself a "virtual
world" is that you could in principle bring the remote devices into
coincidence with the user's real position. E.g., you could wear a HMD
with cameras on the outside, showing you just what you would see
without the HMD. If the resolution etc. were good enough, and you came
up with some great way to get the accommodation right, and you had
full field of view covered, et cetera, then this device would just be
a fancy set of sunglasses: you are still looking at the real world,
but with some device in between you and it. I would *not* call this a
virtual world: it is the real world! Of course you will have
"presence". You are also using "VR technology" to bring it about. I
would not call it a virtual world unless there were some virtual
objects being inserted into the images that are not in the real world.

The next most obvious example of infrared vision is I guess a more
difficult case to categorise. You are looking at the real world,
except that the infrared part of the spectrum is being mapped into the
visible. You still have presence. Maybe "perception-transformed real
world"?

=====================================================================
Dr John P. Costella    School of Physics, The University of Melbourne
mailto:jpc@physics.unimelb.edu.au   http://www.ph.unimelb.edu.au/~jpc
Phone: +61 3 9344-5435   Home: +61 3 9768-9268   Fax: +61 3 9347-4783
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