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

[Jim Crowell <crowell@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Joshua N. Rubin wrote:
> I've never really appreciated the 3-DVG effect, but now at least I
> understand it better.  Like wobbling 2.5-D (Wobble-D?), it sounds as if it
> would work best with one eye completely covered.
> 

For many images I think it does, but it's a bit more complicated than that.

First, because with the 3-DVG you can also induce chromostereopsis (small
disparities that depend on the wavelength of the light) by moving the
pinholes together or apart.  Depending on the direction you move the
pinholes, this will either bring the warm colors closer & the cool ones
farther or vice versa.  So if the picture happens to be set up such that,
say, the red & yellow objects are near & blue & green ones are far, this can
actually enhance the effect.  Of course, for a picture where this type of
relationship between color & distance doesnt hold it will make it look
worse.

Second,  if the scene in the photograph is distant, the fact that there
aren't any binocular disparities between the two images (assuming you
haven't shifted the pinholes) is actually appropriate, and it will actually
tend to look bigger/depthier if viewed with two eyes, provided care is taken
to eliminate all the other flatness cues.

-Jim C.


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