Re: disparity of image sizes

[P3D Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 9:41 AM -0700 7/8/97, P3D George Snowdon wrote:
>        One thing puzzles me.   Because mirrors are used over
>the right eye, the photo-to-eye distance for that eye is about an
>inch more than the photo-to-eye distance for the left eye.
>Therefore, because the right-eye photo seems further away,
>the size of the image on the right retina is smaller than
>the one on the left.
>        Why can I combine these two images of _different scales_
>and, with no effort or strain, see a three-dimensional scene?

The short answer is that your visual system can tolerate a few percentage
points of image  size difference between the two eyes.  If you decrease the
viewing distance (so that the ratio of image sizes increases) you might
start to have trouble fusing them.

-Jim C.

----------------------
Jim Crowell
Caltech Division of Biology
216-76
Pasadena, CA
Tel: (818) 395-8337
Fax: (818) 795-2397
jim@xxxxxxxxxxxxxxx



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