A pseudoscope is a binocular
optic
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
al
instrument that reverses
depth perception
Depth perception is the ability to perceive distance to objects in the world using the visual system and visual perception. It is a major factor in perceiving the world in three dimensions. Depth perception happens primarily due to stereopsis an ...
. 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
Sir Charles Wheatstone FRS FRSE DCL LLD (6 February 1802 – 19 October 1875), was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope (a device for di ...
coined the name from the Greek ψευδίς σκοπειν – 'false view'. The device was used to explore his theory of stereo vision.
Basically, pseudoscopic vision is three-dimensional vision in reverse. For example, in aerial photography, swimming pools appear to look like buildings and buildings appear to look like swimming pools. In red and green plotters like the Kelsh and Multiplex this is achieved by reversing the lenses on the 3D glasses. The images will be reverse order. The right image will be viewed through the left eye, and the left image will be through the right eye.
Effect
Switching the two pictures in a standard
stereoscope
A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image.
A typical stereoscope provides each eye with a lens that makes the ima ...
changes all the elevated parts into depressions, and vice versa. The pseudoscope also changes convex into concave, and high-relief into low-relief.
History
Before the pseudoscope itself was created intentionally, it existed in binocular instruments as an imperfection. The first binocular microscope was invented by the Capuchin monk
Cherubin d'Orleans. 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.
The instrument subsequently fell into complete neglect for nearly two centuries. It was revived in 1852 by
Charles Wheatstone
Sir Charles Wheatstone FRS FRSE DCL LLD (6 February 1802 – 19 October 1875), was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope (a device for di ...
, who published his ideas in his 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
John Leonard Riddell (February 20, 1807 – October 7, 1865) was a science lecturer, botanist, geologist, medical doctor, chemist, microscopist, numismatist, politician, and science fiction author in the United States. He was born in Leyden, Massa ...
(1807–1865) devised his binocular microscope, which contained the essentials of Wheatstone's pseudoscope.
[''Binocular Instruments'', from a classic 1911 encyclopedia]
References
External links
Further reading & commercial pseudoscopeMake your own Pseudoscope for 10 dollarsHistory of design prismatic pseudoscope
{{Stereoscopy, state=expanded
Optical instruments
Optical illusions
Experimental psychology