Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!mit-eddie!mit-amt!tuna!jh
From: jh@tuna.MIT.EDU (John Underkoffler)
Newsgroups: comp.graphics
Subject: Re: 3d Computer Generated Holography
Message-ID: <632@mit-amt.MEDIA.MIT.EDU>
Date: 30 Aug 89 03:49:46 GMT
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In-reply-to: mcdonald@uxe.cso.uiuc.edu's message of 29 Aug 89 16:18:00 GMT



$^!@~ )*%#@	However, the problem is luckily not so computationally
$^!@~ )*%#@ intractable as Ms./Mr./Dr. Ingoldsby fears. There are many ways
$^!@~ )*%#@ to cheat. One of these is that we can dispense quickly with
$^!@~ )*%#@ vertical parallax: because your eyes are situated horizontally
$^!@~ )*%#@ (in order to fill out your face, as my colleague Mr. Halle noted),
$^!@~ )*%#@ most people don't notice if they cannot look over or under objects.

$^!@~ Unfortunately, doing this generates a flat, unlifelike image.
$^!@~ You can't look under or over objects, true, but the subjective 
$^!@~ effect is even worse than that.
$^!@~ 
$^!@~ In our Illini Union museum room, about 100 yards from my office, 
$^!@~ is presently a large display of holographic art, some real
$^!@~ 3D, some 2D-ish. Believe me, the real Ohhhhhhhh's come from the
$^!@~ folks looking at the full 3D transmission ones!!!
$^!@~ 
$^!@~ Doug McDonald


Eliminating vertical parallax does not generate flat, unlifelike images.
Bad rendering generates flat, unlifelike images.

	If the two eyes of a non-deformed viewer are looking at a
stereogram and are intercepting two different-viewpoint views which
are indistinguishable from the real-life views she would be
intercepting by viewing an analagous real scene instead, then of
course her psychovisual perception is identical to that engendered
by the real scene. If, on the other hand, the views have been
rendered on a Sinclair ZX80 running CrayolaRealistic BlenderMan,
then her wonderfully perceptive visual processing faculties will
feel understandably put out.

	It is my long-distance guess that the Illini Union museum room
does not, at this time, feature any holographic stereograms which
have been recorded with the proper geometry and whose views have
been rendered in a manner worthy of, say, Edward Hopper's admiration.
This is a pity. The museum room is invited to examine some of our
latest efforts in the field of synthetic holography, which humbly
proffer startling solidity and tangibility and have generated their
own little smorgasboard of Ohhhhhhhh's.

					John Underkoffler
					Tweezermaster,
					Spatial Imaging Group
					MIT Media Laboratory
					jh@media-lab.media.mit.edu