Crossword clues for optical illusion
Longman Dictionary of Contemporary English
Wiktionary
n. An image that is visually deceptive or misleading.
WordNet
n. an optical phenomenon that results in a false or deceptive visual impression
Wikipedia
An optical illusion (also called a montasir) is an illusion caused by the eye and characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source. There are three main types: literal optical illusions that create images that are different from the objects that make them, physiological illusions that are the effects of excessive stimulation of a specific type (brightness, colour, size, position, tilt, movement), and cognitive illusions, the result of unconscious inferences. Pathological visual illusions arise from a pathological exaggeration in physiological visual perception mechanisms causing the aforementioned types of illusions.
Optical illusions are often classified into categories including the physical and the cognitive or perceptual, and contrasted with optical hallucinations.
Physiological illusions, such as the afterimages following bright lights, or adapting stimuli of excessively longer alternating patterns ( contingent perceptual aftereffect), are presumed to be the effects on the eyes or brain of excessive stimulation or interaction with contextual or competing stimuli of a specific type—brightness, color, position, tile, size, movement, etc. The theory is that a stimulus follows its individual dedicated neural path in the early stages of visual processing, and that intense or repetitive activity in that or interaction with active adjoining channels cause a physiological imbalance that alters perception.
The Hermann grid illusion and Mach bands are two illusions that are best explained using a biological approach. Lateral inhibition, where in the receptive field of the retina light and dark receptors compete with one another to become active, has been used to explain why we see bands of increased brightness at the edge of a color difference when viewing Mach bands. Once a receptor is active, it inhibits adjacent receptors. This inhibition creates contrast, highlighting edges. In the Hermann grid illusion the gray spots appear at the intersection because of the inhibitory response which occurs as a result of the increased dark surround. Lateral inhibition has also been used to explain the Hermann grid illusion, but this has been disproved. More recent empirical approaches to optical illusions have had some success in explaining optical phenomena with which theories based on lateral inhibition have struggled (e.g. Howe et al. 2005).
Optical Illusion is the eleventh album by Russian rock band Splean, released on October 8, 2012 on Navigator Records.
Usage examples of "optical illusion".
If it were magic, I could snap my finger and the rabbit would be its normal self again in a normal cage -- and then you would know you were witnessing an optical illusion.
It was an optical illusion of the quadrimanual locomotion-quaddies even looked more human in free fall.
For an instant Daniel thought the movement was an optical illusion.
He was a young male, earless, with smooth skin that was painted or tattooed in swirling colors and patterns that made the thranta rider himself look like an optical illusion.
Bey stared at those piercing eyes, and after a few seconds the unmoving features before him seemed to shift and flow, reassembling themselves like an optical illusion to a different and familiar pattern.