From: well!naimark@apple.com (Michael Naimark)
Subject: Re: More on VR Architectures [LONG]
Date: Sat, 6 Apr 91 17:38:27 pst


There are several references to cameras and displays made here that concern
realworld recording on which I'd like to comment. Realworld recording (for
realworld simulation or, perhaps more interesting, for abstraction) is often
assumed as trivial or possible at some future time. It ain't that easy.

Disney's CircleVision (nine screen 35mm cylindrical theater) has NO stereoscopy.
If two camera pods could be placed interocular distance apart (which they can't,
resulting in hyperstereoscopy) and two projectors were dedicated for each of the
nine screens (ie., via polarized filters and glasses), the degree of parallax
would change from normal stereoscopic to zero to pseudoscopic as the viewer's
head rotates 180 degrees. This "stereoscopic panorama dilemma" is also true for
shooting realworld images for goggles (like shooting with two fisheye lenses).

The Aspen Moviemap (as well as Polenque, Paris, and Golden Gate) were shot to
maximize user control, such as shooting via distance triggering rather than time
triggering and shooting for "seamless" match-cuts at nodes, but are ultimately
lookup media with minimal computation needed (searching videodisc frame
numbers). Consequently, the end-user can never travel where the camera didn't
shoot. (A favorite flame of mine is that while much of the computer community
dismisses this as not virtual reality, they continue to call their little green
cones "trees.")

Aspen was digitized into a cartoon-like 3D model, by brute force (students) lead
by Walter Bender. The opus document of what it takes to automate this process is
Michael Bove's PhD dissertation "Synthetic Movies Derived from Multi-Dimensional
Image Sensors" (MIT Media Lab 1989). It's exciting and depressing: this is not
going to happen tomorrow. Human's are particularly good at recognizing what is
important in an image and workstations could be optimized to make digitization
less brute force and more the artform that it is.

Cameras could also be optimized for digitization into 3- or 4- D models:
"spacecode" (my term for the sensing and recording of spatial data), z data
sensing, panoramic optics, and auxillary data tracks for annotation would be
good starts. My experience with major cameras and camera companies (ie., Sony)
is that they haven't a clue how, or why.