P3D Re: Stereo Nomenclature

[Bruce Springsteen <bsspringsteen@xxxxxxxxx>]

[returning to the original subject line]

Larry Berlin asks:

>So what does Bruce think now? Does Ortho still need a makeover?

Well, yes - or at least it needs to stop slouching and hiding behind
potted plants.
So far, I am unmoved from my vision of a better-organized nomenclature,
though I sympathize with Abram's crowded breast! ;-)   For that reason, I
am very interested in learning the intentions, history and details of
Donald Wratten's brave efforts.  If you are out there, sir, and have not
been put off by this lurching on-line discussion, I would like to learn 
about your experience with these issues.  I promise not to make
suggestions at this stage of your work. :-)

I fear that "Springsteen's Nomenclature", while it has an undeniable
appeal, is an overstatement of what I have done.  The truth is I have only
rearranged existing definitions, redrawing some boundaries to clarify some
(IMO) muddy concepts and inappropriately classified effects, eliminating
details and terms from the broad definitions that are more applicable to
narrow practical problems.  Again from Goethe:  "Everything has been
thought of before, but the problem is to think of it again."

Some definitions are subjective/phenomenological:
"Orthostereoscopy:  The recreation of a scene as perceived in reality."

Some definitions set conditions only in terms of the results sought:
"Orthostereoscopy:  Reproduction of a scene in its full natural shape,
size and distance." 

Some definitions impose minimal technical requirements to achieve those
ends, applicable in the widest possible circumstances (my goal):
"Orthostereoscopy:  Viewing a scene taken with a stereo base equal to the
average human interpupillary, under the same angle of view as in
recording.

Some definitions address narrow circumstances, without reference to
general cases:
"Orthostereoscopy:  Viewing your transparencies, taken with the same
separation as your eyes, in a viewer with the same focal length as the
camera lenses."

Some definitions impose values (NOT my goal):
"Orthostereoscopy:  The only correct and worthwhile way to do stereo!"

The definitions I find in my books on stereo are all peculiar combinations
of the various kinds above.  Talk about confusing the beginners!  I am a
beginner, or was one not so very long ago.  When I am learning something
new, I like basic definitions that are neither too fuzzy and
philosophical, nor too technically narrow for application in the broadest
circumstances, as I confront different situations down the road.  This is
the sort of definition I was aiming for in my original posting, as a
sample of how that might be done.  I trust that there is ample room for
improvement of my effort.  As to excessive abstraction, an abstract
definition doesn't preclude more concrete ones in practice, but it can
provide a benchmark to refer them to when necessary.  The definition of a
meter is far more precise than almost anyone has need for, but the precise
definition needs to exist.   

My other specific idea was to draw a clear distinction between a) scaling
with stereobase and b) preserving forms in their correct proportions by
matching viewing perspective to recording perspective.  The reason is I
think these are very different aspects of the stereo problem, with very
different roles in what we are calling "realistic", and too often confused
with one another in beginners' - and experts' - discussions.  (I have
examples, but am reluctant to drag them out.)  The best way I saw to do
this is to remove hyper and hypo stereo from the world of "deformations"
caused in non-ortho viewing, and allow them to stand as deliberate choices
by the recorder, similar to the decision to use black and white film over
color, time exposure over frozen action, and so on.

I am especially pleased with my idea (we always think our own children are
beautiful) of recording a real or imagined scene as the *encoding* of a
spatial "message", which then is *decoded* by some viewing method which
reproduces the geometric arrangement of all the elements in the recorded
scene.  My mnemonic (not really a mathematical equation) for the "key" to
decoding was Av = Ar (again not original in concept - it is familiar to 2D
photographers, who only need to do it once).  This key will accurately
reproduce the spatial "message" before the eyes; what the observer makes
of that message in their mind is then up to them.  By analogy, I may
encode an email message "Life is good" in a pattern of electrons which is
sent across the world to be decoded at a computer in another country.  If
that computer has the correct key, it will decode the message as written -
there is nothing subjective about that.  Slight flaws in decoding might
render it as "Lyf iz gud" which might still be understandable to the
reader, though distorted, a tolerable "deformation" perhaps.  But the
"correct" decoding is the same for all recipients, and may be stated as a
rule.  How they then perceive the meaning of the message, and their
tolerance for "deformations" that may occur, is beyond prescription, and
takes us into Abram's realm of individual variation and the mysteries of
the mind.   I have no intention of going into that realm, nor do I see a
necessity to when making ortho-definitions, deformation definitions, and
the like.

So why have I, a dilettante, rushed in where experts fear to tread?  I
don't generally like to use quotations in argument, because it is so easy
to find an out-of-context quote to support any opinion, but I'll make an
exception today.  A real philosopher, Socrates, said a couple of millennia
ago:

"The beginning of wisdom is the definition of terms."

And Oliver Wendell Holmes, who created the most successful stereoscope of
the previous century, also created Oliver Wendell Holmes Jr.,  who said:

"A word is not a crystal, transparent and unchanged; it is the skin of a
living thought and may vary greatly in color and content according to the
circumstances and time in which it is used."

With affection,
Bruce (Blaspheming the P3D gods and corrupting the newbies.) Springsteen 



 


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