(Redirected from Mach band)'Mach bands' are an
optical illusion named after
Ernst Mach. It refers to bands adjacent to a light to dark
gradient that appear lighter or darker than justified by the underlying light (
luminance, see figure).
The effect is one of increased, local, perceived brightness on either side of a luminance gradient, like that of a
spatial high-boost filter. It is usually supposed that this effect is caused by
lateral inhibition of the receptors in the eye. An alternative explanation is that the effect is explained by the fundamentally statistical strategy of visual perception, representing the common occurrence of highlights and lowlights in association with luminance gradients.
References
Mach bands as empirically derived associations, Lotto RB, Williams SM, Purves D, , , Proceedings of the National Academy of Sciences, 1999
See also
★
Cornsweet illusion
★
Lateral inhibition
External links
★
Demonstration of the Mach band
★
Laboratory of Dale Purves, MD