Stereo difficulty

[P3D Jonathan Gross <catalyst@xxxxxxxxxxxx>]

>Interestingly enough a vietnamese friend couldn't see the slides in my
>little viewer...

> I don't think it was the same problem, but a coworker of mine (he's not asian 
> either) was telling me that he was unable to see in 3D due to a problem with 
> his right eye.

I tried to remember where I read this, but approximately 10% of the
general population does not perceive depth with stereopsis; instead they
use the other depth cues of  obstruction,  scale and relative motion,
perspective, shading and shadows,  and color shift.  Whenever I present
stereo slides to a group of people, I always ask before and after if
there is someone who does not really see "it".  Because 10% is a small
percentage, this sampling technique is really only valid for groups
whose size is about 10 or more (someone with a stronger background in
statistics may be able to calculate what the size is for a given level
of confidence).  I have found informally that one out of ten is about
right.

When I ask the subject about their lack of stereopsis, they usually
mention a known problem with one of their eyes, even if they were not
previously aware of their lack of stereoscopic acuity.  One of the
impediments to  the commercial use of stereoscopy has to do with the
wisdom of using a visual technique which is not effective on 10% of the
population.

Ive often wondered what other correlations one might discover about
these people.  Do they have more automobile accidents?

Jon Gross

Jon Gross


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