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How do optical illusions work?

Optical illusions arise at healthy people rather often during all life as they are absolutely normal state depending on specific conditions or a structure of human eye.

The reasons of some illusions are established, but most of them have no scientific explanation, to this day. The phenomenon is caused by features of a structure of an organ of vision belong to the known types of optical illusions - it is the irradiation, optical illusions, which are accompanying an astigmatism Marriott's illusion ( so-called, blind spot).

Today doctors and psychologists managed to create an unusual classification, which divides all types of optical deceptive perceptions on different signs. Therefore, there are illusions of perception of the sizes of a subject or of figure, a ratio of the sizes of a figure depending on a background, deception of color and contrasts. And also, there is a wrong perception of depth and the movement, the effects of perceptual readiness and after-effects, seeming imaginary and impossible (areal, beyond reality, artificial) figures.

Optical illusion represents wrong visual perception of reality, a subject or visible phenomena as a result of features of a structure of the visual device, and also under the influence of a concrete environmental conditions (refraction of beams at a heavy rain, distortion of outline of objects or figure in twilight). In addition, such disease as color blindness, has no relation to optical illusions.

All system of the visual device including eyes, nervous cells and the terminations thanks to which the visual signal comes to a brain, and immediately that part of a brain which is responsible for a visual perception of the phenomena or objects is responsible for visual perception.

The reasons of some illusions are established, but most of them have no scientific explanation, to this day. The phenomena is caused by features of a structure of an organ of vision belong to the known types of optical illusions - it is the irradiation, optical illusions, which are accompanying an astigmatism Marriott's illusion ( so-called, blind spot).

Today doctors and psychologists managed to create an unusual classification, which divides all types of optical deceptive perceptions on different signs. Therefore, there are illusions of perception of the sizes of a subject or of figure, a ratio of the sizes of a figure depending on a background, deception of color and contrasts. And also, there is a wrong perception of depth and the movement, the effects of perceptual readiness and after-effects, seeming imaginary and impossible (areal, beyond reality, artificial) figures.

Optical illusion represents wrong visual perception of reality, a subject or visible phenomenon as a result of features of a structure of the visual device, and also under the influence of a concrete environmental conditions (refraction of beams at a heavy rain, distortion of outline of objects or figure in twilight). In addition, such disease as color blindness, has no relation to optical illusions.

All system of the visual device including eyes, nervous cells and the terminations thanks to which the visual signal comes to a brain, and immediately that part of a brain which is responsible for a visual perception of the phenomena or objects is responsible for visual perception.

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Widely known optical focus - soaring in air is an example (levitation). The illusions recreated by the person on the known natural deception isn't less interesting - it is the mixed optical illusions - illusory visual pictures.

If artificially created optical illusions have strict explanation (play with light, mechanical design), the natural illusory deception almost never has science-based solutions.

There are many examples of natural illusions, most of them concerns the irradiation. For example, when viewed at a distance squares of white and black, then white drawings are perceived by man larger, though in reality the pictures are the same geometric shapes. Moreover, researchers have long pointed out that an increase in the distance to the image, the illusion is enhanced - this is irradiation.

This kind of illusion is due to a specific effect, which occurs due to the structural features of the eye - every point of light tone "imprinted" on the retina as a circle (spherical aberration), and the perimeter of this circle bordered with bright tape, due to which increases the surface, with images of black everything happens on the contrary. All experiments directed to irradiation identification have confirmed her presence at all people.

The illusion of "a blind spot" provoking feature of the structure of the visual apparatus, or rather, the existence on the retina a small area in which there is no sensitivity to light. If the beam is reflected from any point of the object, it gets in this area, the mind is not able to receive it, so some of the items seem to be invisible and the picture is completely distorted. A few examples of perfectly illustrates the presence of this optical illusion.

If we look at the picture with a closed left eye at a distance of 20-25 cm, it becomes invisible big circle but smaller circles on the sides of the size has seen very well. But when looked at cross located at the bottom of the circle is only partly visible. This example is called an optical illusion (illusion Mariotte).

There are examples that prove the origin of optical illusions with astigmatism. If you look closely at the inscription, made with black letters, one eye, one of the characters will be seen blacker if rotated inscription at different angles, then a deeper black color will seem different letters.

Astigmatism is expressed in different convexity (in different directions) the cornea, this feature is almost everyone (congenital astigmatism, a recognized congenital disease has only 10% of people).

Examples of this phenomenon are many, if a long time to look with one eye at a short distance on the image, focusing on the top white square, then quickly disappear from sight lower white stripe (doctors attribute this fatigue of the retina).

One more wrong perception of objects arises in case of special types of lighting, this deception is called illusions of color. One of the unique effects is the experiment with lighting - if two lighters placed by a special method (distance of 20 cm) light vertically delivered subject, its shadow will appear on the white screen.

After that, on both lamps attire light filters of different bright color (for example, blue and red) - these colors will also be reflected in the screen. But... if to remove one color filter, then on the screen color in perception of the person, will remain. Extraordinary striking and unexpected example of optical deception when color is imprinted in a brain, this just deceptive perception of sight.

There are many theories that attempt to explain this phenomenon, but we must admit that not one of them does not give a complete picture of optical illusion.

Violation of color perception is also considered a type of optical illusion, but its consequences can be far not as harmless as one might expect. Road services are well aware that most of the accidents reported at intersections at dusk on statistics.

This results from the fact that sights is reconstructed from color perception to light (more sensitive).

Artificial creation of optical illusions gives the chance to experts to reveal certain regularities of visual perception therefore psychologists pay to experiments very much attention, the tests which are thought up by them serve as "a litmus piece of paper" for clarifications of the hidden mechanisms of sight. For this purpose experts think out various test experiments during which an eye has to in unusual conditions solve complex of problems.

The role of optical illusions has always been high, in ancient times they were used by shamans, the world-famous painting of Leonardo da Vinci are full of hidden optical illusions (he owns several treatises on the subject of illusions). Leaning Tower of Pisa "crashes" visual only 10% for reasons related to the construction, 90% of them - it's an optical illusion.

The researches connected with geometrical optical illusions from the scientific point of view for the first time were conducted in 1854 by Oppel. Their works tried to clear as it is possible more stoutly the nature of optical and psychological perception numerous for illusion.

Interesting illusion is represented by the circles applied on paper which under special conditions begins to rotate in consciousness of the person, it will be more correct to tell, the person perceives them rotating. The closer the image is considered, the circles rotate quicker. At the moment when the distance is so big that all picture "is located" under review, circles in general stop.

In the special way the placed coffee grains, also cause optical deception, it seems to the person that they move, make the chaotic wavy movements, reminding lifting and lowering by the person of a thorax at a breath and an exhalation (naturally, it is visual illusion, actually coffee grains aren't mobile).

Also the three-dimensional graphics, or creation 3D - drawings, volume drawings, more and more gaining popularity around the world belongs to artificially created illusory deception. The essence of such drawings or stereography is based that, the images created by 3D - technologies, purchase effect of dimensions.

The main difference of three-dimensional pictures from the two-dimensional image consists in transfer of a geometrical projection of a three-dimensional subject to the plane with use of special programs. As model for creation 3D - the drawing any subject, real objects or the natural phenomena can serve.

The dimension illusion created by three-dimensional graphics widely is used in architecture and construction - "live" walls, floors, "moving" facades significantly diversify apartments and exteriors of buildings.

Scientists always, studying optical illusions, concentrated, as a rule, on psychological and medical factors of this phenomenon, and only in recent years experts have come to an unusual conclusion that the natural illusions of sight existing in daily occurrence can influence scientific observations, bringing a perception inaccuracy that can lead to wrong conclusions.

Not so long ago when studying features of monocrystals experts have found out that optical illusions constantly brought to wrong, strongly distorted (25% and more) to results of assessment of the valid geometrical guidelines in this connection, it is necessary to check all visual perceptions by large-scale rulers.

Moreover, practically all difficult geometrical figures cause the visual illusions parallel to the line in a large number applied on the sheet of paper seem wavy, concentric circles begin "to move". Deception of curve mirrors, familiar to all since the childhood of optical deception treats the same type of illusions so kindly.

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