Re: Stereopis Proof

[P3D Jim Crowell <crowell@xxxxxxxxxxxxxxxxx>]

At 6:32 PM 6/10/96, P3D wrote:
>
>     But seriously, *absolute* fixation isn't needed for the proof... as I
>sit here looking across the breakfast bar counter into the kitchen, if I
>*seriously restrict* my gaze to the canister on the counter, even if I shift
>my gaze around the canister and detect depth in it, the microwave, blender,
>etc. on the counter across the kitchen are doubled and do not show any depth
>other than from secondary influences. Closer objects on the computer desk are
>the same, but more out of focus.
>

Sensitivity to stereo goes waaaaay down in peripheral vision, &
there are claims that some people lose it entirely in large
parts of the field ("stereo-blind spots").  Generally speaking,
you can only see large, broad depth variations in the periphery,
but once you can see them most people think they look as large
as they would in central vision.  Some people continue to see
increases in depth with increases in disparity even after they
can't fuse the images anymore (that's true in central vision as
well).  Peripheral stereo is very idiosyncratic.

-Jim C.


------------------------------------------------
Jim Crowell
School of Optometry
360 Minor Hall
University of California
Berkeley, CA 94720-2020
(510) 642-7679
jim@xxxxxxxxxxxxxxxxx
http://john.berkeley.edu/IndividualPages/jim.html



------------------------------