Re: [photo-3d] Hyper active

[Brian Reynolds <reynolds@xxxxxxxxx>]

John A. Rupkalvis wrote:
> With the hyperstereo viewing device, it is the two inboard mirrors
> that are spaced such that their optical centerlines are about 65mm
> apart.  The outboard mirrors are spaced much further apart, the
> optical centerline distance determining the hyperstereo base.
> Otherwise, the configuration is the same as that of a camera image
> splitter.
> 
> The results when looking at the images as seen through the center
> pair of mirrors can be quite fascinating.  This is especially true
> with wider stereo bases and more distant subjects, because when
> something is so far away that there is little depth perception with
> the unaided eyes, it is possible to make the depth impression quite
> exaggerated, which in some cases is quite startling.
> 

During WWII German artillery spotters used a device that could match
that description for ranging artillery shots.  From the outside it
looks like a long tube with binocular eyepieces at the middle on one
side and lenses on each end on the other side.  I don't know if they
used mirrors or prisms to bend the optical path.  My military
modelling books are all in storage so I also can't tell you the
official name of this device.

The various other armies also had similar devices.  The British
version is called a Coincident Optical Rangefinder, and Barr & Stroud
are credited with make the first practical ones in 1888.

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
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