Re: [photo-3d] Re: Telestereoscope

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

A bit of trivia.  The first camera image tube used for commercial broadcast
television was named the iconoscope.  Universally used until it was rapidly
replaced by the Image Orthicon in the late 1940's and early 1950's.

Of perhaps more interest to stereographers, the television iconoscope was
used in several early stereoscopic television experiments.   Being very high
resolution, it produced some startlingly realistic stereoscopic images
(albeit monochrome).

With a sensing surface measuring about 3 x 4 inches (75 x 100mm), it could
easily effect resolutions in excess of 1000 lines horizontally and
vertically.    Of course, these figures could only be achieved on special
one-of-a-kind receivers equipped with high resolution yokes around the neck
of the picture tube (CRT).  This pretty much limited such experiments (as
well as the stereoscopic experiments) to wired (connected by special coaxial
cables) setups in the lab.  To my knowledge, none of these early experiments
were ever broadcast over air.  The bandwidth available just did not permit
it.

The complete industrywide replacement with Image Orthicons (which had a
receiving surface, or "matrix" as it was called back then, that was only
about an inch across) pretty much ended both the stereoscopic and the high
resolution (high definition!) experiments.

The Image Orthicon, although a much lower resolution device, was much higher
in sensitivity, and more linear in color response yielding more believable
gray tones (sort of like comparing orthochromatic with panchromatic b & w
films).   This, plus much lower replacement cost, led to a very rapid
industrywide conversion.

Before this transition, some experimenters tried to compensate for the
iconoscope's nonlinear response by placing color filters in front.  But, it
was already too slow to allow this in most practical applications; (white
flame carbon arc lamps had to be used for any interior shots).

Somebody may have been reading Drouin and figured that by then the name
"iconoscope" would be in the public domain.

JR

----- Original Message -----
From: "Dr. George A. Themelis" <drt-3d@xxxxxxx>
To: <photo-3d@xxxxxxxxxxx>
Sent: Sunday, October 22, 2000 12:44 PM
Subject: Re: [photo-3d] Re: Telestereoscope


> At 10:26 AM 10/22/00 -0700, you wrote:
> >So what would you call that?  A lilliputiscope?
>
> Drouin (1894) shows an instrument that he calls iconoscope.
> Via mirrors you can look at a real object with both eyes and
> see it totally flat (eliminate relief).
>
> George
>
>
>
>