[photo-3d] Re: Stereo x-rays, ortho/pseudo, front/back , up/down

[abram.klooswyk@xxxxxx]

John Rupkalvis:
>Pseudo, by itself is a rather loose term, as it simply means 
>"false".  Scope means "the range of one's perceptions".  
>Therefore, pseudoscopy means "a false range of perceptions".  
>Stereoscopists have specialized this to apply to images that 
>are transposed (etc)

Of course many technical and scientific terms have Greek or 
Latin roots, but once coined, many have _specific_ meanings. 
Charles Wheatstone coined the term "Pseudoscope" in 1852 in 
his second reading on binocular and stereoscopic phenomena, 
and the year after he used the adjective "pseudoscopic" in a 
reading on binocular microscopy in a specific way.
So there cannot be any misunderstandings about this term.

My point on the viewing of stereo x-rays of known asymmetrical 
objects is that, regardless of any copying, rotation, 
transposition, left-right flipping or whatever messing around, 
when you in the end see a 3D percept of the object, whether 
you see it from the back or from the front, left-right flipped 
or upside-down, in _all_ cases you can see whether it is 
pseudoscopic or not. 
Therefore I could see that one of Peter Abraham's shells was 
presented pseudoscopically (at first).

>Orthoscopy is not the opposite of pseudoscopy.

It surely is. Orthoscopic is not short for orthostereoscopic. 
This terminology in stereoscopy also has 19th century roots, 
it has been used in English, French, German and other 
languages, in many books and articles on stereoscopy. 
In Germany even in an official DIN stereo terminology (the DIN 
is comparable to the ASA). Recently the I.S.U. glossary with 
the same usage of the terms has been published in 
"Stereoscopy". This are not just arbitrary terms. (But as I 
recently wrote indeed "orthoscopic" also has meanings in other 
fields).

In radiology "focus", "tube window", "diaphragm", "collimation" 
have _specific_ meanings. After focus size, x-ray scatter is 
the main factor in causing x-ray image deterioration. 
The amount of scatter mainly depends on x-ray quality (mainly 
set by voltage), object size and diaphragm opening.
(Let's stop discussing radiology here).

 Abram Klooswyk 
 
 



 

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