The Ouchi Illusion, named after the Japanese artist Hajime Ouchi who devised it, is an extraordinary optical illusion that creates a sensation of depth and motion in a flat, static image. At the heart of this illusion is the way it plays with the perception of depth and movement in our visual system.
The illusion consists of a central disk pattern, usually consisting of vertical bars in a checkered pattern, set against a background of a contrasting horizontal checkered pattern. When you view the image, the central disk appears to float or jitter above the checkered background, especially when you move your eyes around or scroll the image.
The illusion works based on the differences in how our visual system processes the distinct patterns in the image. As you move your eyes or the image, the eye movements in horizontal and vertical directions are processed differently by different sets of neurons in your brain.
The checkered pattern is more resistant to the eye movements parallel to the pattern, while the disk pattern appears to move more. Therefore, the neurons processing the disk signal that it’s jittering, while the neurons processing the background signal that it’s relatively stationary.
This discrepancy in perceived motion between the disk and the background causes the brain to interpret them as being on different planes. Therefore, the central disk is perceived as floating above the checkered background.
This illusion underscores the complexities and capabilities of the human visual system and how it can process and interpret visual information. It’s a striking demonstration of how our brain interprets depth and motion, even in two-dimensional images.