Which surface looks darker? The top or the bottom?
Now cover edge connecting the surfaces (you can just put your finger right over it). Which looks darker now?
The two surfaces are actually identical, but our brains perceive a brightness difference in part because of the luminance changes right at the edge.
This is a really strong example of the Cornsweet Illusion , named after vision scientist Tom Cornsweet who did a great deal of research on the illusion many years ago. In the illusion, the positive and negative luminance gradients at the edge lead to the perception of vastly different surfaces: a dark luminance gradient leads to the adjoining surface being seen darker; a light luminance gradients leads to the adjoining surface being seen lighter. Covering the edge - where the luminance gradients occur - enables you to see that the two surfaces are actually exactly the same.
No comments:
Post a Comment