[photo-3d] Re:wobble stereo/motion parallax

[Jim Crowell <crowell@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Rod Sage wrote:
> I often find myself looking out the side window of the car as I drive to
> work. On an open road with little foreground distraction, watching the
> trees, homes etc. which are 1/4 mile or more off,  move relative to the
> distant mountains, there can be an amazing sense of stereo, almost
> hyperstereo. I always consider this to be similar to the "Pulfrich
> Effect" where objects are moving or spinning in one direction.
> Rod S.

Actually, it's not, oddly enough.  The Pulfrich Effect is mediated by stereo
vision; darkening one eye's image causes it to be processed more slowly,
which in turn causes different views of the object (from different instants
in time) to be used in creating the 3-D percept.  In other words, it's the
positions of features in the two eyes that are being matched up.  With
motion parallax, the motion itself is used (via an evolutionarily more
primitive system) to reconstruct the shape.

Tony Alderson wrote:
> As for jittervision, pogoscope, visidep, wobbly-bobbly; well, I'll have
> more to say about that in a couple days. For now, I am larfing
> uncontrollably. This is a technique tried and discarded long ago; all it
> shows is the utter truth of evolution. (Of academic interest, of course,
> but with little practical value.) Depth perception in animals (including
> homo sapiens) is many-threaded, one shouldn't have tunnel vision about
> stereopsis.

Sure, it's not likely to replace any of the standard viewing methods, but
"commercial success" and "practical value" are hardly synonymous.  As
someone pointed out, it could be useful for showing people without stereo
vision what the heck the fuss is about.

For anyone who's playing with this, try viewing the images through a pinhole
(as small as you can see the image clearly through).

-Jim C.

-------------------------------------
Jim Crowell, Ph.D.
Dept. of Psychology
Cognitive/Experimental Group
216 Lazenby Hall
Ohio State University
Columbus, OH 43210
mailto:crowell@xxxxxxxxxxxxxxxxx
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http://vision-lab.psy.ohio-state.edu/crowell/