[photo-3d] Re: The "Wobble" effect

[Peter Homer <P.J.Homer@xxxxxxxxxxxxx>]

"Joshua N. Rubin" wrote:
>
> Try this:  Go to the large snowflake "wobble" image at
> http://www.lpsi.barc.usda.gov/emusnow/stereo/1.htm and view the image while
> covering one eye.  To my eye, it's not only 3-D, it's actually slightly more
> 3-D than if I look at it with both eyes.

I was not able to view the "wobble" effect at this site because I dont have
pentium but I believe the bit about it being better with one eye. One of
the earliest examples of this type of stereo seems to have been the
rotoreliefs of Marcel Duchamp they consisted of concentric rings on a disc
alternately offset in opposite directions. This is in effect the same as
domes or cones with symetrical rings marked on them viewed slightly from
one side. The mirror image is the opposite eye view and the two viewed
together give a stereo image of receding and aproaching domes and/or cones.
Wheatstone himself produced some of his first stereo drawings with such
symetrical shapes rendered unsymetrical by a view from one side combined
with the mirror image for the other view.

However Duchamp actualy rotated his discs which presented a mirror image
every 180 degrees. This produces the same stereo image because it seems the
brain retains a memory of the image on one side and combines it with the
other. This does not require two eyes and in fact the normal two eye stereo
seems to contradict the effect because the image is actualy flat, and they
are best viewed with one eye.       P.J.Homer