T3D Re: viewing disparity

[Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 5:20 AM -0700 9/23/98, John Slivon wrote:
>I have a simple question. I have recently learned how to view stereo pairs
>using the crossed eyes method. I have noticed that when viewed cross-eyed,
>the stereo image appears to be about 60% of the size of either image of the
>pair. When I view images using the parallel method, the stereo image appears
>to be the same size as either image of the pair. Am I just screwed up or is
>there some "scientific" explanation worthy of tech-3D for this?
>John Slivon

Perfectly normal.  It's called "vergence micropsia". The convergence angle
of your eyes has an effect on how big things look (which makes sense; if
your eyes are converged, then you must be looking up close & whatever
you're looking at must be small).  However, this effect is basically
unnoticeable unless your eyes  are converged pretty close in.

It's the main drawback of cross-eyed viewing...

-Jim C.

-------------------------------------
Jim Crowell
Caltech Division of Biology
Mail Code 216-76
1200 E. California Blvd.
Pasadena, CA 91125
jim@xxxxxxxxxxxxxxx
http://vis.caltech.edu/~jim/Home.html


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