P3D Re: Stereo Nomenclature (part 3[a] of 3)

[Larry Berlin <lberlin@xxxxxxxxx>]

> Date: Wed, 15 Dec 1999 
> From: Bruce Springsteen <bsspringsteen@xxxxxxxxx>
> .........
> Bruce's Heterodoxy Finally Exposed:
> 
> Definition I:  I define "stereoscopic recording" as making two perspective
> projections (arbitrarily called "left" and "right") of a real or imagined
> scene, photographed, drawn or otherwise produced, taken from two station
> points separated by any distance with their optical axes parallel and
> directed at the same point in infinity, and perpendicular to the line
> which includes both station points, the visual cones of both projections
> taking in the same angle of view.

***** Expansion note... The above applies to perspective projection
only.
Parallel projection can and does exist and as a recording circumstance 
it's subtly different. There is an interocular and two views, but the 
optical axes from the viewpoints toe-in towards the center of interest. 
There is no infinity point except as imposed by the perspective viewing 
arrangements.


> 
> Definition II:  I define "stereoscopic viewing" as two projections "left"
> and "right" made as in Definition I, presented directly or indirectly to
> the corresponding eyes of an observer, such that a "cyclopean image" is
> formed in the mind, wherein disparities between the two images are
> interpreted as a single three dimensional scene viewed binocularly.

****  I understand you are borrowing a term from elsewhere. However I 
will point out it's a significant mis-use in light of current knowledge. 
*Cyclopean* CANNOT accurately apply to the inner mental experience 
of stereoscopic vision as a Cyclops has only one eye, and would see 
the world strictly in 2D.

(and getting by in 2D it would loudly proclaim, -what is it with these 
two eyed creatures? I see just fine with one eye...- )

The synthesis of two images into one fully structured 3D and centralized 
comprehension is inherent ONLY to two eyed creatures. It is completely 
an ERROR to apply the term Cycolpean to this unquestionably binocular 
function. 

It more appropriately applies to the behavior of TV executives and other 
non-stereoscopically enlightened czars of the 2D information realm. They 
are extremely cyclopean in their outlook on life and business, despite 
having two functinoal eyes of their own.

Cyclopean as a term could ONLY appropriately apply as a descriptive of 
*stereoscopic blindness* (a complete lack of the stereo-synthesis 
experience), either physically induced or mentally adopted. Realize 
that a Cyclops wouldn't know what it was missing. A Cyclops would be 
clueless to understand such a thing. (sounds remarkably familiar!)

As a myth, it's anchor in reality is the notion of having vision, but 
only a limited form thereof. As such it describes most politicians 
both now and throughout history (as well as other classes of humanity's 
various blindnesses in a figurative sense.) It's no wonder such a 
creature was invented!

The only wonder is modern stereoscopically interested folk attempting 
mistakenly to apply the term to themselves! Let's hope it's less true 
among those who best appreciate the truth in stereoscopic vision 
phenomena.

> ............
> Why am I so uncomfortable with the classic definition of 
> "orthostereoscopy (Recording Base = Viewing Base while Recording 
> Focal Length = Viewing Focal Length)?  I've never felt it quite 
> "hangs together" and I've been trying to decide exactly why for 
> some time.
> ...........

****  I too have that experience with the definition. I've concluded 
that it's because stereo relationships preserved in a carefully made 
pair of images don't lose their obvious value merely because of 
not being precisely ortho either in the taking or in the viewing.

However, as a theoretical point of scientific principle, I do 
understand the precise notion, though feel it's most often over-rated 
in importance. I mean, how often do you reject the idea of buying a 
teddy bear for your kids because it's not ortho to the size and 
appearance of a real bear? 

The magic for stereo takes place in the mind of the observer. It 
matters very little if the perceived image is precisely ortho with 
the exact and original configuration. The image can still be 
perceived and interpreted along with it's depth components on 
an internal relational basis, and fully enjoyed too.

Ortho, per se, is merely the central anchor point to a very flexible 
medium. Not the definition of the medium itself, thankfully!
-- 
Larry Berlin

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