No Subject

[telscope@xxxxxxxxxx (Peter Abrahams)]

>
>...
>
-Mapping the earth in 1996 is incredibly hi-tech, but the hundreds of
topographic maps of the US were made with stereoscopic photos taken from
airplanes.  The workers who viewed these photos used a technique of watching
a white disk that seemed to float over the photos, and matching the
perceived elevation of the disk to the photo of the landscape.
>...
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My background is as a film cameraman (over 30 yrs) and I think
-by comparing comments about seeing in general and talking about
images- that my eyesight is quite (MHO) acute, when I use proper
glasses.

I once filmed at a .mil mapmaking facility and got to peek through
one of those white disk machines mentioned in Peter's post.

Geez! Talk about feeling useless. One turned two heavy steel
wheels to move the dot, and I felt as inept as I have ever felt
at anything. I couldn't tell -for a single moment- if I was on 
or off 'target (?)'. Mind you, when viewing a normal stereo image I
can notice technical deficiencies, misalignments, etc. quite
easily.

The fellows operating those machines, *THEY* had stereoacuity!!!

pno


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