Re: Stereogram on the "Stereo Window"

[P3D Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Sat, 21 Jun 1997 
>From: P3D Paul Talbot  writes:
>......................... (I said)..........>
>> while the window redefines itself for each example by the new
>> relationship.
>
>I have no idea what that part means.

******  The window is the plane of coincidence so if you move the image so
it includes the plane of the window, the window's actual content has changed
so things looks somewhat different than when everything is behind the
window. George described it as appearing to become larger.

>
>Then on Fri 20 Jun Larry wrote, in part:
>
>> ****  I submit that if you pay close attention, there is a perceptible
>> enlargement of the window continuously as it recedes into the image
>> with any chip adjustment.
>
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>I'm confused, Larry.  On Thursday you seem to be saying the
>window is fixed and doesn't move, relative to the observer,
>when the chips are adjusted.  On Friday you seem to be saying
>something quite different.  Did DrT win a convert to his point
>of view?

*****  No, in this point I'm referring to the perceptual change that
happens, not the actual change. I maintain that the window as defined by the
mount remains just as it was, spatially. However, as the window content
changes, it appears to enlarge or shrink according to the direction of
movement relative to the image contents. 

>
>On the experiment I described with the 4P mount and the window
>violations, the sides of the window that have no violations still
>appear to be at their usual close location; that part of the window
>has *not* receded into the scene.  That suggests to me that it is
>the visual confusion caused by the violations, not the chip spacing
>itself, that is altering the perceived location of the window.

*****  I understand what you are seeing. If you try freeviewing the slides
themselves ( because it's easier to be aware of the window edges themselves
in spatial relationships) as you move the chips, it's logical and consistent
to understand that as the scene is moved any tiny amount, relative to the
window, the window position relative to the scene changes relative position
equally and changes actual content. If you use a slide with mostly empty
space and a central object for your extreme movement experiment, you will
not have any window violations, yet can become aware of the position of the
window itself being changed to some point behind the central object. The
slide you are talking about happens to have objects on the side to create a
*violation*. If they weren't there, the window still changes in relative
position for any change of the chips. You can't move the one aspect without
affecting the other. You can learn to recognize the position of the window
in any of these circumstances. George just happens to prefer thinking in
terms of window motion alone and ignores the image shifts relative to the
viewer.

Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/
http://3dzine.simplenet.com/


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