Illusion/perception

An illusion is distortion of the senses, revealing how the brain normally organizes and interprets sensory stimulation.

Depth sensation is the ability to move accurately, or to respond consistently, based on the distances of objects in an environment.

In the late forties, visual researcher Adelbert Ames Jr. designed a series of visual illusions to demonstrate how the mind forms hypotheses about reality and depth. In one such illusion, Ames tested aspects of depth perception in a specially designed, distorted room.


Depth perception arises from a variety of depth cues. These are typically classified into binocular cues that require input from both eyes and monocular cues that require the input from just one eye.[1] Binocular cues include stereopsis, yielding depth from binocular vision through exploitation of parallax. Monocular cues include size: distant objects subtend smaller visual angles than near objects.[2] A third class of cues requires synthetic integration of binocular and monocular cues.

Anamorphosis is a distorted projection or perspective requiring the viewer to use special devices or occupy a specific vantage point to reconstitute the image. "Ana - morphosis" comes from the Greek words meaning "formed again."

There are two main types of anamorphosis: Perspective (oblique) and Mirror (catoptric). Examples of perspectival anamorphosis date to the early Renaissance (15th Century), whereas examples of mirror anamorphosis (or catoptric anamorphosis) occurred at the time of the baroque (17th century).





Andria Pozzo's painted ceiling in the Church of St. Ignazio


With mirror anamorphosis, a conical or cylindrical mirror is placed on the drawing or painting to transform a flat distorted image into a three dimensional picture that can be viewed from many angles. The deformed image is painted on a plane surface surrounding the mirror. By looking uniquely into the mirror, the image appears undeformed. Current in the 17th and 18th centuries, this process of anamorphosis made it possible to diffuse caricatures, erotic and scatologic scenes and scenes of sorcery for a confidential public.