P3D Re: PHOTO-3D digest 2567

[boris@xxxxxxxxxxxx (Boris Starosta)]

>Date: Fri, 6 Feb 1998 14:39:25 EST
>From: KenDunkley@xxxxxxx
....
>But Les, both colors lie on a flat surface, and are actually equidistant from
>the observer.  Once you detect the 3-DVG effect you will be able to perceive a
>clear and definite depth distinction between objects in a picture. This

and...

>Date: Fri, 6 Feb 1998 14:20:36 -0700
>From: Bob_Maxey@xxxxxxxxxxxx
...
>Concerning the recently discussed Thing-A-Ma-Jiggey-Do-Wackey for seeing
>stereo in non-stereo images, please someone correct me. Isn't a single lens
>picture just that, a single image? Doesn't stereo require 2 different
>viewpoints stereo? Help me to understand this, or is it an optical illusion
>that looks like stereo?
>
>RM


Bob, you are correct insofar as we might be addressing actual stereo
photography.  However, Mr. Dunkley is providing us with an interesting
_illusion_, not stereo photography.

The impression received by using Dunkley's technique is clearly
"stereoscopic," in that you perceive depth in an otherwise flat photograph.
Naturally it is an illusion.  Given only one image, actual stereo cues do
not exist.

As I tried to explain in my previous post, I believe the effect is caused
by variable chromatic aberration.  As you view objects within the
photograph, different colors are displaced by different amounts,
artificially producing variable disparity among those objects, and
therefore the illusion of "stereo" depth.  The illusion is most easily
recognized in photographs containing strong colors, and barely visible in
B+W photographs.  It is not unlike the view through "chromadepth" glasses,
but more interesting.

I would encourage the various members of P3D, who are knowledgeable with
optics theory (Bercovitz and Abrahams come to mind), to have a look at
Dunkley's site, because the effect really is quite interesting.  (Ken, you
will have to re-announce your URL, because I've lost track of it at the
moment.)

Respectfully submitted,



Boris Starosta

usa 804 979 3930

boris@xxxxxxxxxxxx
http://www.starosta.com
http://www.starosta.com/3dshowcase

"The cut worm forgives the plough."
-Blake

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