[photo-3d] Re: Chromostereopsis

[Jim Crowell <jcrowell@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Dr. Monte Ramstad wrote:
[snip]
> If that's the case, my question is does our brain
> (or optical nerves) attempt to correct for chromatic
> aberrations locally in the field view?  The reason I ask
[snip]

I think it might.  I vaguely remember hearing a talk several years ago at
the Berkeley Optometry School in which they'd worked out how to precisely
compensate for each subject's individual chromatic aberration (I believe
they were less interested in the lateral component of aberration than in the
differences in effective focal length) & it didn't improve visual acuity at
all.

Gabriel Jacob wrote:
[snip]
> 
> I checked the Internet and found most sites mentioning that people
> will see the red closer. A few however did also mention that some
> people will see the opposite (blue closer). They didn't shed any
> more information on why and what percentage. There was also
> some confusion or ambiguities on some of them. What I could
> figure out was the red/blue apparent  distance manifests itself in
> different ways.
[snip]
> 
> This still doesn't explain why Dale and some others see the blue
> boxes as appearing closer. After some experimentation, I think the
> reason might be how one is fixating on the image. Looking at the
> colored boxed with two eyes but using the outer parts of both pupils
> will have a different effect compared to using the inner part of both

Gabriel,

You're on the right track.  Chromostereopsis is caused by a slight offset of
the center of the pupil with respect to the center of the lens.  In most
people this is in one direction (I can't remember if it's inward or outward
& am feeling too lazy just at the moment to work it out), but in a few it's
the opposite.

-Jim C.

-------------------------------------
Jim Crowell, Ph.D.
Dept. of Psychology
Cognitive/Experimental Group
Townshend Hall
1885 Neil Ave. Mall
Ohio State University
Columbus, OH 43210
mailto:crowell@xxxxxxxxxxxxxxxxx
mailto:crowell@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
mailto:crowell.20@xxxxxxx
http://vision-lab.psy.ohio-state.edu/crowell/