T3D Re: acuity enhanced with binocular vision

[Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 9:00 AM -0700 3/20/98, John W Roberts wrote:
>
>>The most obvious reason for improvement would be the simple increase in the
>>number of samples (photons or neural impulses).  There's noise associated
>>with both images (photon noise & neural noise); the photon noise is
>>independent in the two eyes & the neural noise would be at least to some
>>extent, so you'd get some improvement just from doubling the number of
>>relevant photons.
>
>Would you expect comparable improvement by doubling the number of photons
>to one eye, while continuing to deprive the other eye of the image?
>I can tell by looking out the window that I can see details better with
>both eyes than with either eye alone, in bright sunlight. I'm not convinced
>that doubling the brightness of sunlight would result in all that much
>improvement in visibility of details.
>

Right; whether or not photon variability is the source of noise that limits
performance depends on the level of illumination.  It is at lower light
levels, but as you increase light level the signal/noise ratio increases as
the square root of the luminance.  At some point (I'm afraid I can't
remember the relevant luminance, but it's certainly below what you get on a
sunny day) internal noise becomes the more important factor, in which case
the neural site at which it's being added is going to determine whether
there's a monocular/binocular difference...

-Jim C.

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



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