Stereo Window - Poll time!

[P3D Dr. George A. Themelis <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Effect of altering chip placing (relative to mount):

   Chip
 placement    Effect Seen by GT     Effect Seen by PT            
 ---------    -----------------     -----------------
                      []
  close       O       ||Scene       O    []Scene
                      []
   far        O    []   Scene       O    []   Scene

Explanation:  I see the stereo window ([]) moving back and forth with
respect to the fixed scene ([] also changes size, it becomes larger as it
is pushed back.) Paul sees the scene moving back and forth with respect to
the fixed window.

Photo-3d audience, can we have your vote please? :-)

Comments:  

As Paul said, the answer is relative.  We agree that the end result is that
the window and scene come closer to each other when the chips are brought
closer.  The question is, is this achieved by pushing the window away from
the observer or by pulling the scene closer to the observer?  Does it even
matter?

The brain must choose one of the two answers to explain the end result.  I
believe that in most cases it will choose my answer because Paul's answer
requires that the size of the *known* scene is changed.  If the scene was
really coming closer to the observer, then it should be getting bigger and
with more depth, but this is not happening.  On the other hand, the window
is an artificial contraption and it is very easy to perceive it changing in
size.

I realize that by bringing the chips together, I change my eye's
convergence.  If convergence has a strong effect on the depth perceived
then that could support Paul's perception but I believe that convergence is
overridden by stereopsis and recognizable sizes.  I can see however how one
can get Paul's perception in the case of unrecognizable artificial objects
like computer generated wire diagrams, etc.

Question for Paul: Is the size of the objects in the scene changing too? 
How about the size of the stereo window?

Effect of changing viewing FL:

 Lens FL    Effect Seen by both GT and PT
 -------    -----------------------------
 Short      O  []  Scene
 Long       O     []      S c e n e

We agree on that.  Window moves back (it is also physically smaller,
everything is smaller) and scene is "stretched".

-- George Themelis



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