Unusual 3d concept

[P3D sam smith <sam@xxxxxxxxxxx>]

I recently aquired a copy of the 1954 publication " Introduction to 3-D", by
H. Dewhurst, a book mostly  devoted to 3d TV and Motion Picture. While most
of the concepts I can fathom, there are some that have me perplexed.  On
page 60, Under the Viewing Aids chapter, it describes a technique similar to
the parallax stereogram, but using gridded screens.
 "  Left and right-eye pictures seen from a fixed stance are photographed
through a vertical grating in front of the film the width of whose apertures
was equal that of the bars. Such a film projected on to a screen with a
similar grating in front would, when viewed at a particular distance, be
seen stereoscopically."
 So far so good. The book then descibes revisions in this process, such as
"...swinging the camera in an arc centered on the subject with the film
maintained parallel to the chord of transverse 'pans' the compressed
slit-type images across the focal planes at the back of each of the
cylindrical-lens lenticulations of a plastic sheet in contact with the film
emulsion." OK, I'm a little lost on the swinging camera part.
Now things get real complicated. It seems the process had a " striation"
problem when viewing the images. Somone named Savoye had the following solution:
" ..Sayoye enclosed his screen by a rotating truncated cone, apex downwards,
which carried the bars of his grid across a field of view in front of the
screen. The bars decrease in width towards the bottom, and would pass, if
produced in imagination, through the same point through which lines in the
plane of the screen and on the sloping auditorium floor would also
preferentailly pass. The grid cone rotates at some fifteen to twenty
revolutions a minute to give an affective occultation frequency of
forty-eight per second. By such means Savoye has succeeded in eliminating
the discontinuity in the projected images and made the ' striation' of his
grid invisible".
Wow. Rotating truncated cones,affective occultation frequencies.... What
planet is this guy from?
Does anyone back here on earth understand this stuff? Unfortunately no
diagrams were included, and I'd love to see if this concept really works.
Anyone familiar with the writings ( or ramblings) of either H.Dewhurst or
this Savoye fellow might also be able to clue me in.

Sam Smith
sam@xxxxxxxxxxx


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