[photo-3d] Retinal rivalry, find the x differences

[abram.klooswyk@xxxxxx]

George Themelis 20 Feb 2001:
>the audience can find the differences between similar 
>pictures very quickly, thanks to retinal rivalry. 
>I use this trick to amaze my friends and relatives by 
>freeviewing the newspaper cartoons.

I do the same. This is a perfect example of what the French 
call "étaper le bougeois". 
Once I have seen a contest in a toy shop window composed of 
two identical large structures built of Lego stones, some 
1.5 m (5 feet) high. Among hundreds of blocks seven were 
different. (Did I win? No, in a fit of sportsmanship I thought 
I shouldn't profit from free viewing).

A more serious application is in astronomy, many celestial 
body have been discovered by binocular comparison of star 
pictures taken at different times.

It also can be used in radiology. Radiology of course is a 
serious profession, but part of it boils down to finding the 
(7?) differences between (say) chest X-rays from different 
days.

As with the astronomy photographs, finding the differences is 
easier with the "blinking method". For this astronomers have 
shutters in their apparatus, but when doing the newspaper 
cartoon trick you can just move a hand before your eyes, 
covering them alternately. Then the static rivalry effect 
becomes an easy detectable movement. 

Returning to the topic of the list (beware of moderators!), 
this blinking method have been used in projection mounting 
systems. I have seen convincing demonstrations (but I don't 
use such a system myself...).

Abram Klooswyk