T3D Re: Visual acuity = 1' of angle?

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Thu, 9 Jul 1998 03:07:46 -0600
>From: Peter Homer <P.J.Homer@xxxxxxxxxxxxx>
>Subject: T3D Re: Visual acuity = 1' of angle?

>>>So are cones 2 microns or 5 microns on center?
>>>
>>>I'm curious because this has a large effect on the required
>>>resolution of a slide if there is to be no loss in stereo
>>>due to impaired resolution.

>As the test pattern is a simple grid of black and white lines it seems to
>me that the rods should be taking as much or more of a part in resolving
>the image as the cones as they have evolved for black and white vision.
>Cones are for colour and I believe there is evidence that there are at
>least three types for the primary colours. This could mean it would take
>three cones to resolve a single white line as white. There are far more
>rods than cones although the greatest concentration of cones is in the
>Fovea Centralis or yellow spot mentioned in the original text. I canot
>remember if there are more cones than rods in this area but even if there
>are the distance between rods would also seem to be relevant.

But I think the "wiring" is different. If I recall correctly, typically
a batch of rods are hooked up to each ("channel"?) that goes to the brain,
while the cones in the fovea may be close to a 1:1 mapping. Also, I believe
the particular visual centers to which the signals are sent differs between
rods and cones.

Hopefully Jim C will comment - he actually knows this stuff. :-)

John R


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