Index Key:  PHY090
Author:     saintofengineer
Subject:    Amazing Stereoscope
Text:       They call it a stereoscope.  What is it?  How does itwork?

Response #:  1 of 1
Author:      Arthur Smith
Text:        Yeah, I just discovered one of those the other day.  At least, I 
think it is the same thing you are talking about.  Normally, to see a 3-D 
image, your two eyes have to see slightly different versions of the same 
thing, and then your brain does some complicated mathematics to convert the 
two images into a 3-D representation.  Stereo images have been around for 
quite a while, but up until very recently always came in pairs - one for the 
left eye, the other for the right - that are best viewed through a special 
stereo viewer that presents each image to the eye it was intended for.  
Recently, somebody seems to have figured out that by printing an image (of a 
dinosaur or space shuttle) using special patterns, you could combine those two 
images into one.  The result looks like a big mess of these little patterns, 
until your left eye notices the dark/light contours that it was intended to 
see, and the right eye notices the contours it was supposed to see, and 
suddenly the brain transforms that mess of little patterns into a 3-D image of 
a big structure.  It is really pretty neat.