on the right. Spatial frequencies will no longer seem identical: the spatial frequency of the upper lattice will seem higher (denser) than the spatial frequency of the lower lattice [Shiffman, 2008], [Gusev, 2007].
Figure 1.2.16 Mach bands.
Figure 1.2.17 Spatial frequency.
Consider the effects based on the phenomenon of lateral inhibition, these include the lattice of Hermann and light contrast. Figure 1.2.18 shows the German grid (German physiologist Ludimar Hermann in 1870), it consists of a white square grid pattern on a black background. The lightness of the white stripes is the same along the entire length; however, phantom gray spots will appear at their intersections. They are due to the suppression of the neural activity of neighboring cells of the retina. If we concentrate our gaze on a separate point of intersection, the gray spot will disappear. In this case, the image is projected on the central fossa, and gray spots appear on other crosshairs, which will be projected on the peripheral areas of the retina with high sensitivity.
Figure 1.2.18 Hermann’s grid.
Figure 1.2.19 “Complementary” grid of Hermann.
You can observe the colored spots on the crosshairs; for this you can choose a grid and a background complementary in color. Such a color grid is shown in Figure 1.2.19, blue spots will appear on the yellow cross hairs [Abbasov, 2019]. When scaling Hermann’s grid, the “phantom” spots will be more stable; for this it is necessary to move the pattern away to the projection of the grid on the retina. From a long distance, the stripes will narrow and phantom spots will be visible regardless of the gaze fixation.
1.2.7 Light Contrast
A further example of the spatial interaction of neighboring areas of the retina is light contrast. It lies in the fact that the lightness of a small closed figure depends on the intensity of lightness of the massive background area (Figure 1.2.20) [Abbasov, 2016]. From the point of view of light reflected by them, all four central gray circles are identical; however, it seems that they differ in lightness. A circle on a dark background (left edge) seems lighter than a physically identical circle on a light background (right edge). Therefore, this means that the perceived lightness of the surface depends on the intensity of its background.
1.2.8 Object Identification
There are several theories of identification based on the distinctive features of surrounding objects. At the initial stage of anticipation, there is a fast processing of the information received, which allows you to perceive the basic, very simple and noticeable distinctive features of the object, the so-called perceptual primitives. The surfaces differ from each other by the simplest elements of the texture - by the textones, the specific distinguishable characteristics of the elements forming the texture. In Figure 1.2.21, one can observe a textural background from the set of letters P, Б, Ь; however, to find the letter B on such a background, concentration of attention will be required.
Figure 1.2.20 Light contrast.
Figure 1.2.21 Texture pattern of various letters.
According to another theory, object recognition begins with processing information about a set of primitive distinguishing features. Any object of three-dimensional space can be decomposed into a number of geometric primitives (geons: sphere, cube, cylinder, cone, pyramid, torus, etc.). On the basis of various operations of combining, intersection of surfaces of primitives, you can create new or analyze existing objects. Similarly, any letter can be obtained from a set of lines and curves. According to the theory of geons (geometric ions) by Biederman [Shiffman, 2008], a set of 36 geons will be enough to describe the shape of all the objects that a person is able to recognize. According to the experiments, the object is recognized; its geons are perceived as well. Usually, the description of an object includes not only its features, but also the relationships between the constituent parts. After describing the shape of the object, it is compared with an array of geons that are stored in memory, and the most appropriate match is found.
1.2.9 Color Vision Abnormalities
Color vision for most people is normal, but certain anomalies are characteristic of some. In people with color vision abnormalities, the quantitative ratio of primary colors is different from normal color vision. Anomalies of color vision are usually hereditary, and are associated with a lack of cones of a certain type. Based on the decoding of the genetic codes, each cone contains a photopigment with its own gene. The photopigment genes are found in the X chromosome; women inherit one X chromosome from their mother and one from their father.
To ensure normal color vision, at least one chromosome must contain genes of normal photopigment synthesis. Males inherit the X chromosome from the mother and the Y chromosome from the father. If the only X chromosome does not contain the gene for normal photopigment synthesis, then the son will have an anomaly of color vision. If a color anomaly has arisen in a woman, then this means that she has two defective X chromosomes and all her sons are doomed to a color anomaly. Therefore, when inheriting color vision anomalies, the genetic mechanism does not work in favor of men. Color vision anomalies exist in 8% of males and 0.5% of females.
One of the first color vision anomalies in the eighteenth century was described by the English chemist John Dalton. By chance, he found himself suffering from a color perception abnormality. During a ceremony, he donned a crimson mantle instead of a black academic mantle. He saw the blush on the cheeks of his girlfriend as green spots; the world was painted in a marsh-brown range. Since then, the anomalies of color vision (color blindness) have become known as blindness. To explain his anomaly, Dalton suggested that it was caused by the pathological staining of the vitreous body, which played the role of a filter. He made a will according to which, after death, his eyes should be opened in order to experimentally confirm the theory. Subsequent studies did not confirm Dalton’s theory, but the scientist’s eyes are still kept in the Manchester Museum of Great
