- Pseudoscope
. It is used to study human stereoscopic perception. Objects viewed through it appear inside out, for example: a box on a floor, would appear as a box shaped hole in the floor.
It typically uses sets of optical prisms, or periscopically arranged mirrors to swap the view of the left eye with that of the right eye.
Purpose
In the 1800s
Charles Wheatstone coined the name from the Greek ψευδίς σκοπειν -- "false view". The device was used to explore his theory of stereo vision. [ [http://books.google.com/books?id=0_QMAAAAIAAJ&pg=PA146&dq=pseudoscope&as_brr=1 "Experimental Psychology"] p.146 by Edward Bradford Titchener, Macmillan, 1906]Effect
Switching the two pictures in a standard
stereoscope changes all the elevatedparts into depressions, and vice versa. The pseudoscope produces these inversions also, itchanges convex into concave, and high-relief into low-relief.But the pseudoscopic inversion of a complicated picture — a landscape, streets, etc., produces a bewildering impression. It seems as if all the objects — men, trees, etc., had been placed in a depression of the earth, and yet everything remains in its place. Therefore, nearer objects appear very large, because we imagine them to be at a great distance, and more distant objects smaller, because they seem to be nearer. [ [http://books.google.com/books?id=TBQzAAAAMAAJ&pg=PA137&dq=pseudoscope&as_brr=1#PPA145,M1 "The Five Senses of Man"] , p.137, Julius Bernstein, Appleton, 1876]
History
. Because his instrument consisted of two inverting systems, it produced a pseudoscopic impression of depth by accident, although not recognized by microscopists of the time.
, who published his ideas in his second great paper "On Binocular Vision," in the "Philosophical Transactions" for 1852. Wheatstone's paper stimulated the investigation of binocular vision and many variations of pseudoscopes were created, chief types being the mirror or the prismatic.
In 1853 the American scientist
John Leonard Riddell (1807-1865) [ [http://asaweb.huh.harvard.edu:8080/databases/botanists?id=102014 "Harvard U. Herbaria"] ] devised his binocular microscope, which contained the essentials of Wheatstone's pseudoscope. ["Binocular Instruments", from a classic 1911 encyclopedia]References
External links
* [http://www.grand-illusions.com/pseudoscope.htm commercial pseudoscope]
* [http://pseudoscope.blogspot.com/ Make your own Pseudoscope for 10 dollars]
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