[photo-3d] Re: stereomonoscope ?

[abram.klooswyk@xxxxxx]

>>Niranjan P. Ghate
>>I am looking for a device that will let both my eyes
>>see from the same angle...
George Themelis 14 Feb 2001:
>I have heard of a device like that, called iconoscope.

The iconoscope to which George refers is mentioned in an  
originally French book by Drouin, 1894, a facsimile edition 
of the English translation was produced by David & Susan 
(http://stereoscopy.com/reel3d/book-drouin.html).

The name "iconoscope" was given to it by the French 
ophthalmologist Javal in 1866. The device was in fact a 
reversed telestereoscope (without lenses). It reduces the 
effective eye separation, but not to zero. It seems that a 
similar scheme was used by Wenham already in 1853 for 
microscopic stereoscopy. 

Drouin himself proposed a device which reduces the eye 
separation to zero, but it worked with a rotating drum and 
could only be used for objects of limited size.

Then Carl Zeiss patented some devices, the best is the 
"Synopter" from 1907, based on reflecting rectangular prisms 
and a beam splitting surface. Another form uses the same 
optical scheme with a half silvered mirror and some ordinary 
mirrors. With these devices both eyes are optically placed at 
the same position. This device is a true beam splitter (not 
image splitter).

(I remember having seen a scheme in recent years where a 
similar device was used, but reversed, to make direct 
anaglyphs with a single camera.)

In a paper by  Koenderink et al. from Utrecht University, the 
Netherlands, interesting experiments are described with the 
synopter. They have compared  pictorial relief under 
monocular, 'synoptic', and natural binocular viewing.

For observers with normal stereovision a painting is flat, but 
the "flatness cues" are removed by monocular and synoptic 
viewing. But for only one of the three subjects (the three 
authors) synoptic viewing was superior to monocular viewing. 
(Monocular viewing of paintings was already advised by Leonardo 
da Vinci.)

(Ref.: Koenderink JJ, van Doorn AJ, Kappers AM  
"On so-called paradoxical monocular stereoscopy", 
Perception 1994;23(5):583-594.  
The abstract of their paper is one line at Pubmed, 
http://www.ncbi.nlm.nih.gov/entrez/  , 
but it doesn't cover the paper very well in my opinion.)

Abram Klooswyk