Best Optical Illusions of 2007 | The Thinking Blog ~ Knowledge Grows When Shared
Make Money Online Freelance Jobs

25 May 2007

Best Optical Illusions of 2007

Contests have been at the core of scientific tradition since the beginning, and that’s no coincidence: contests bring out the best in us. For example, the annual Nobel Prize winners are awarded a medal and a cash prize for a variety of scientific and creative endeavors. The Best Visual Illusion of the Year Contest follows in this important tradition and hopes to bring visual science to public awareness.

The winner of the contest is remarkable. Not only it's an illusion but also explains more about our visual system.

From the page:

Here is a novel illusion that is as striking as it is simple. The two images of the Leaning Tower of Pisa are identical, yet one has the impression that the tower on the right leans more, as if photographed from a different angle.

The Leaning Tower Illusion

The reason for this is because the visual system treats the two images as if part of a single scene. Normally, if two adjacent towers rise at the same angle, their image outlines converge as they recede from view due to perspective, and this is taken into account by the visual system. So when confronted with two towers whose corresponding outlines are parallel, the visual system assumes they must be diverging as they rise from view, and this is what we see. The illusion is not restricted to towers photographed from below, but works well with other scenes, such as railway tracks receding into the distance. What this illusion reveals is less to do with perspective, but how the visual system tends to treat two side-by-side images as if part of the same scene. However hard we try to think of the two photographs of the Leaning Tower as separate, albeit identical images of the same object, our visual system regards them as the ‘Twin Towers of Pisa’, whose perspective can only be interpreted in terms of one tower leaning more than the other.

The same also works for three or more images of the Leaning Tower of Pisa:

The Leaning Towers Illusion

If you can't believe your eyes, then here is a flash animation to prove it:

At least it's not this kind of an optical illusion:

The Lifting Keyboard Illusion

Loading.. Digg It! Stumble It Reddit