Re: Viewing angle

[T3D Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 10:18 AM -0700 10/30/97, T3D wrote:
>
> To a good approximation, human visual resolution drops off as the
> reciprocal of the angle from the optic axis.
> (linear resolution proportional to (theta+1)^-1)
> This assumed photopic lighting conditions, where cone-mediated vision
> dominates, and monochrome stimuli.
>
> The only major 'lump' (trough) is the blind spot, at approx 12 degrees to
>one
> side (nasal retina, temporal visual field), but this is limited to one
> direction, a small segment of the annulus around the optic axis, and for the
> two-eyed readers of P/T3D, we have cover for that 'lump' anyway. Acuity
> (resolution) 'contours' are slightly elliptical - acuity being a little
>better
> along the horizontal meridian as compared to above or below the centre of
> regard.
>
> Roughly.
>
> Jeremy

What he said.  If you're away from the fovea I think it also depends on the
orientation of the contour in a polar-coordinate sort of way (i.e. contours
parallel to a line from the fovea vs. perpendicular to it), but I can't
remember which is better.

-Jim C.


----------------------
Jim Crowell
Caltech Division of Biology
216-76
Pasadena, CA 91125
Tel: (818) 395-8337
Fax: (818) 795-2397
jim@xxxxxxxxxxxxxxx



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