P3D Re: The Stereo Window

[aifxtony@xxxxxxx (Tony Alderson)]

Greg Wageman wrote (P3D digest 3430):
>We must then agree to disagree.<

I don't have a big problem with this. We seem to be mainly arguing about
terminology. I haven't seen any evidence Greg doesn't understand stereo
viewing, he just doesn't like the words we're using. I can understand some
of his points.

he continued:
>A "window" is something one sees through. If the border, edge or "window"
>is behind all the subject matter, it is not a "window" because one does
>not "see through" it. <

Well, I can't agree with this because it leads to contradictions and
confusion in discussing the issue. I repeat, your definition is too narrow,
you restrict yourself to a mere portion of the concept of the stereo
window.

The term "stereo window" is analogous to (and borrowed from) the attributes
of a physical window, but it is not necessarily the same. This often
happens when a word is appropriated from past experience to describe some
new observation.  But Greg's definition fails for both the stereo window
and a physical window.

More thought experiments:
If the panes of a physical window are painted opaque, does it cease to be a
window? If it is night outside, and we can't see anything in the dark
BEHIND the window, but we can see a fly IN FRONT OF THE WINDOW, is there a
window anywhere in our view? If these things are not windows, what do we
call them? Does one have to be able to see _through_ a window at any given
moment for the thing to be a window?

We place two chips of a stereo pair in a combined mount (e.g., RBT,
Realist, Albion, etc.). Our first iteration has all the points of the
stereo image in front of the stereo window. Of course , according to Greg,
there is no stereo window in this case so the above sentence is
meaningless; except this situation is clearly possible (and common) and
there is no other available term but "stereo window." Greg himself is
forced to use ""window"" to make his argument. Our second iteration is to
slide the chips apart, so the stereo image recedes into the frame. At some
point, according to Greg, a stereo window has appeared.  Greg has not yet
offered a term for the condition before the stereo window appears.

It is hard for me to see why there is no stereo window if the image is in
front of the frame. Consider a stereo slide with some portion behind the
frame, but some object protruding through the frame. Is there no stereo
window for the image portion in theater space? If so, why not for the case
where all the image is in front?

Greg continues and askes:
>I notice that Tony did not respond to my query, does a 2D photograph have
>a "stereo window"?<

>Everyone seems to be ducking that question!<

I must have missed that post. I've been scrolling through the digests
rather quickly, I guess I threw the baby out with the bathwater. It's a
good question.

But sure, a 2D photo has a stereo window. (At least for people with
stereopsis.)  A 2D picture is a special case of the stereo photograph,
where only one of the views is present!  Alright, maybe I'm being a little
puckish here, but we've all seen flattie dupes mounted in a stereo slide.
There isn't a stereo photograph, but there is a stereo window. Of course,
there is little utility in using that term in common conversation, but I'm
arguing for a broad definition, and Greg is right, this fits within my
definition. Not that I'm going to dig in my heels on this part!  (Good
debater's move, Greg!)

And finally:
>Well, that's some progress. We have reached a consensus that not all 3D
>images have a window.<

Gee, I conceded that from the first about immersive VR.

Anyway, this whole discussion reminds me of an exchange I had some time ago
with Charles Smith about the term "convergence" in stereography. Except I
was I the in the Greg Wageman role. Quite amusing, actually. (Charles got
me into "check", if not "checkmate." Not that I've given up even yet!)

Tony Alderson

P.S. I'm also reminded of the jurist who opined: "I may not be able to
define pornography, but I know it when I see it!"

So if porn is undefinable, and the stereo window is undefinable, how do we
discuss stereoscopic sexual images? ;-)

It's a rhetorical question! No answer is expected!  :)




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