May 8, 2012

12 Optical Illusions Made from Shadows

 

Below you will find a collection of optical illusions created using shadows in a variety of ways. Many of these have been floating around the Internet for quite some time but I thought it would be fun to compile all of the most interesting ones into a single post. Some of the examples below may not technically be considered optical illusions, please do not get too upset.

 

 

A and B are the same shades of gray

 

shaow illusion same color checkerboard with cylinder 3 12 Optical Illusions Made from Shadows

 

The visual system needs to determine the color of objects in the world. In this case the problem is to determine the gray shade of the checks on the floor. Just measuring the light coming from a surface (the luminance) is not enough: a cast shadow will dim a surface, so that a white surface in shadow may be reflecting less light than a black surface in full light. The visual system uses several tricks to determine where the shadows are and how to compensate for them, in order to determine the shade of gray “paint” that belongs to the surface.
 
The first trick is based on local contrast. In shadow or not, a check that is lighter than its neighboring checks is probably lighter than average, and vice versa. In the figure, the light check in shadow is surrounded by darker checks. Thus, even though the check is physically dark, it is light when compared to its neighbors. The dark checks outside the shadow, conversely, are surrounded by lighter checks, so they look dark by comparison.
 
A second trick is based on the fact that shadows often have soft edges, while paint boundaries (like the checks) often have sharp edges. The visual system tends to ignore gradual changes in light level, so that it can determine the color of the surfaces without being misled by shadows. In this figure, the shadow looks like a shadow, both because it is fuzzy and because the shadow casting object is visible.
 
The “paintness” of the checks is aided by the form of the “X-junctions” formed by 4 abutting checks. This type of junction is usually a signal that all the edges should be interpreted as changes in surface color rather than in terms of shadows or lighting.
 
As with many so-called illusions, this effect really demonstrates the success rather than the failure of the visual system. The visual system is not very good at being a physical light meter, but that is not its purpose. The important task is to break the image information down into meaningful components, and thereby perceive the nature of the objects in view. [Source: Edward H. Adelson]

 

shaow illusion same color checkerboard with cylinder 2 12 Optical Illusions Made from Shadows

 

shaow illusion same color checkerboard with cylinder 1 12 Optical Illusions Made from Shadows

 

 

 

Place your thumb in the middle, between the two squares

 

optical illusion same gray color thumb over middle 12 Optical Illusions Made from Shadows

 

 

Shadow Art

 

shadow art building blocks kumi yamashita 12 Optical Illusions Made from Shadows

Artwork by Kumi Yamashita

 

 

dirty white trash 1998a 12 Optical Illusions Made from Shadows

 

 

Overhead Shadows

 

camel shadows from above aerial george steinmetz 12 Optical Illusions Made from Shadows

 

zebra shadows aerial from above national geographic 12 Optical Illusions Made from Shadows

Photograph via National Geographic

 

 

Shadow People

 

shadow optical illuion people 12 Optical Illusions Made from Shadows

 

sneaker shadow shoes silhouette 12 Optical Illusions Made from Shadows

 

 

Shadow Love

 

shadow kiss meet serendipity 12 Optical Illusions Made from Shadows

 

shadow doggy from behind 12 Optical Illusions Made from Shadows

 

 

Hovering

 

standing beside dark spot on ground hovering 12 Optical Illusions Made from Shadows

 

hover boat shadow illusion 12 Optical Illusions Made from Shadows

 

flying carpet shadow optical illusion 12 Optical Illusions Made from Shadows

 

 

 

 

 

 

If you enjoyed this post, the Sifter highly recommends:

 

 

hover cover 12 Optical Illusions Made from Shadows

 

 

 

 

 

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