The Pseudoscope

Depth perception is really neat. We have it because we have eyes that point forward, and because of the distance between them (called the interpupillary distance). This distance creates binocular disparity, which is the difference between the location of an image seen by each eye. Close one of your eyes and look at an edge, then do the same with the other eye, and you'll see what I mean. Because of these two images projected on each retina, we have a sensation of depth (although depth is not only because of this and of course is also reliant on visual cues in the environment).



This is all well and good and relatively obvious, but imagine depth perception was reversed. Such is the occurrence when using a device called the pseudoscope, which makes objects appear inside out. Apparently inside out is the opposite of depth, which sort of twists me up when I try to think about the semantics of that philosophically. The word pseudoscope is Greek and means "false view"; this term was coined by English scientist and inventor Sir Charles Wheatstone, who also invented the more useful brother of the pseudoscope, the stereoscope (as well as a bunch of other incredible devices, including the kaleidophone, which makes sound vibrations visible). But while the stereoscope is certainly useful, the pseudoscope is odd and surreal, and I have an admittedly useless tendency to prefer things that are the latter.



The pseudoscope works by reversing the images from a normal stereoscope, which makes all the parts that are convex concave and vice versa. Basically what it does is, by using optical prisms or mirrors, trade the view of the right eye for that of the left eye and vice versa.

Here is a neat-o video on making your own pseudoscope: