The Ouchi illusion, illustrated above, is an illusion named after its inventor, Japanese artist Hajime Ouchi. In this illusion, the central disk seems to float above the checkered background when moving the eyes around while viewing the figure. Scrolling the image horizontally or vertically give a much stronger effect.
The illusion is caused by random eye movements, which are independent in the horizontal and vertical directions. However, the two types of patterns in the figure nearly
eliminate the effect of the eye movements parallel to each type of pattern. Consequently,
the neurons stimulated by the disk convey the signal that the disk jitters due to
the horizontal component of the eye movements, while the neurons stimulated by the
background convey the signal that movements are due to the independent vertical component.
Since the two regions jitter independently, the brain interprets the regions as corresponding
to separate independent objects (Olveczky et al. 2003).
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