What is stereoscopic vision?

Vision is vital to most livingorganisms. It helps to properly navigate and respond to the environment. It is the eyes that transmit about 90 percent of the information to the brain. But the structure and placement of the eyes of different representatives of the living world is different.

What vision happens

There are the following types of vision:

• panoramic (monocular);
• stereoscopic (binocular).

With monocular vision, the world aroundperceived, as a rule, with one eye. This type of vision is typical mainly for birds and herbivores. This feature allows you to notice and respond to impending danger in time.

Stereoscopic vision is inferior to panoramic lower visibility. But it has a number of advantages, one of which is a three-dimensional image.

Distinctive features of stereoscopic vision

Stereoscopic vision is the ability to see the world around with two eyes. In other words, the overall picture is made up of the fusion of pictures that enter the brain from each eye at the same time.

With this type of vision, one can correctly estimate not only the distance to a visible object, but also its approximate dimensions and shape.

In addition, stereoscopic vision hasone significant advantage is the ability to see through objects. So, if you put in front of your eyes, for example, a fountain pen in an upright position and look alternately with each eye, then a certain area will be closed in the first and second cases. But if you look with two eyes at the same time, the pen stops being a hindrance. But such an ability to “look through objects” loses its strength, provided that the width of such an object is greater than the distance between the eyes.

The peculiarity of this type of vision in various representatives of the globe is presented below.

Features of the structure of the eyes of insects

Their vision has a unique structure.Insect eyes look like a mosaic (for example, wasp eyes). Moreover, the number of these mosaics (facets) of different representatives of this representative of the living world is different and ranges from 6 to 30,000. Each facet perceives only part of the information, but in total they provide a complete picture of the surrounding world.

And insects perceive color gamut differently than humans. For example, a red flower that a person sees, the eyes of a wasp are perceived as black.

Birds

Stereoscopic vision in birds is the exception rather than the rule. The fact is that most birds' eyes are located on the sides, which provides a wider viewing angle.

This type of vision is inherent mainly to birds of prey. This helps them correctly calculate the distance to moving prey.

But visibility in birds is significantly lower than, for example, in humans. If a person is able to see at 150 °, then birds are only from 10 ° (sparrows and bullfinches) to 60 ° (owls and nightjars).

But do not rush, claiming that the feathered representatives of the living world are deprived of the ability to fully see. Not at all. The fact is that they have other unique features.

For example, owls have eyes closer to the beak.In this case, as already noted, their viewing angle is only 60 °. Therefore, owls are able to see only what is directly in front of them, and not the situation on the side and behind. These birds have another distinctive feature - their eyes are fixed. But at the same time they are endowed with another unique ability. Due to the structure of its skeleton, owls are able to turn their heads 270 °.

Fish

As is known, in the absolute majority of fish specieseyes are located on both sides of the head. They tend to monocular vision. The exceptions are predatory fish, especially hammerhead sharks. For centuries, people have been interested in the question of why this fish has such a head shape. A possible clue was found by American scientists. They put forward a version that the hammerhead sees a three-dimensional image, i.e. she is endowed with stereoscopic vision.

To confirm their theory, scientists conductedexperiment. To do this, sensors were placed on the heads of several species of sharks, which were used to measure the activity of the brain of fish when exposed to bright light. Then the subjects were placed in an aquarium. As a result of this experience, it became known that the hammerhead was endowed with stereoscopic vision. Moreover, the accuracy of determining the distance to the object is the more accurate, the greater the distance between the eyes of this type of shark.

In addition, it became known that the eyes of the hammerhead rotate, which allows it to fully see the environment. This gives her a significant advantage over other predators.

Animals

Animals depending on species and habitatendowed with both monocular and stereoscopic vision. For example, herbivores who live in open spaces, for the safety of their lives and a quick response to impending danger, should see as much space as possible around them. Therefore, they are endowed with monocular vision.

Stereoscopic vision in animals is characteristic.for predators and inhabitants of forests and jungles. First, it helps to correctly calculate the distance to its victim. The second such vision allows you to better focus the view among the many obstacles.

For example, this type of vision helps wolveswith long pursuit of prey. Cats - with lightning attack. By the way, it is in cats, thanks to parallel-located visual axes, the viewing angle reaches 120 °. But in some breeds of dogs, both monocular and stereoscopic vision are developed. Their eyes are located on the sides. Therefore, to view the subject at a distance, they use the front stereoscopic vision. And for a review of nearby objects, the dogs are forced to turn their heads.

For residents of treetops (primates, squirrels, etc.), stereoscopic vision helps in the search for food and in calculating the trajectory of the jump.

People

Stereoscopic vision in humans is not developed withthe birth itself. At birth, babies cannot focus on a particular subject. Their binocular vision begins to form only at 2 months of life. However, in full, children begin to correctly navigate in space only when they begin to crawl and walk.

Despite apparent identity, eyespeople are different. One of them is leading, the other is driven. For recognition it is enough to conduct an experiment. Position the sheet with a small hole at a distance of about 30 cm and look through it at a distant object. Then alternately do the same, covering the left and right eyes. The position of the head should remain constant. That eye for which the image does not change position, and will be leading. This definition is important for photographers, videographers, hunters and some other professions.

The role of binocular vision for a person

This type of vision has arisen in man, as in some other representatives of the living world, as a result of evolution.

Конечно же, современным людям не нужно охотиться for prey. But at the same time stereoscopic vision plays a significant role in their lives. It is especially important for athletes. So, without an accurate calculation of the distance, biathletes will not hit the target, and gymnasts will not be able to perform on the balance beam.

This type of vision is very important for professions that require instant reaction (drivers, hunters, pilots).

And in everyday life without stereoscopic visionnot enough. For example, it is quite difficult, seeing with one eye, to push a thread through the eye of a needle. Partial loss of vision is very dangerous for humans. Seeing only one eye, he can not properly navigate in space. And the multi-faceted world will turn into a flat image.

Obviously, stereoscopic vision is the result of evolution. And only the elect are endowed with it.