Recognition and Perception of Images. Группа авторов

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 Britain [Fershild, 2004].

      There are three types of color vision abnormalities: abnormal trichromatism, dichromatism and monochromatism. Normal color vision is three-component, and such color vision is called normal trichromatism. People with abnormal trichromatism need different quantitative ratios of primary colors. There are the following forms of abnormal trichromatism:

      The protanomal has an insufficient amount of long wavelength L cones, so it is not sensitive enough to shades of red. Dalton himself suffered from this anomaly. According to the theory of Goering, they cannot be implemented red-green opponent mechanism, with the result that they are unable to distinguish between reddish and greenish shades.

In deuteranomals, sensitivity to green tones is reduced, which is a result of a lack of M cones; they also have difficulty distinguishing reddish from greenish tones. In tritanomals, there is a low sensitivity to violet tones characteristic of short-wave light, an insufficient number of S cones, less common than the rest. Tritanomals cannot distinguish between yellowish and bluish shades.

Figure 1.2.22 shows some test images for determining color vision anomalies. For people with normal color vision, various combinations of numbers and geometric shapes will be visible in the pictures [Abbasov, 2019].

      People suffering from dichromatism need only two colors to reproduce all color tones, instead of three, like people with normal color vision. Monochromatism is also encountered – an extremely rare defect in color vision. To reproduce all the color tones of the spectrum, monochromes need only one primary color. People with such an anomaly of color vision can be called “color blind”; usually they do not see any colors at all.

      Anatomically, the retina of the deuteranomals, protanomals and tritanomals differ from each other in the number of cones containing blue, green and red pigments. The cause of a defect in color vision is the relative lack of a specific cone pigment. Many people with color vision defects are not aware of this until a certain point. Some well-known artists also suffered from these anomalies (for example, Russian painter M. Vrubel with his gray-pearl scale; French artist, graphic artist S. Merion).

      It should be noted that there is also the phenomenon of subjective colors. Under certain conditions, black and white stimuli can cause a sensation of color. Intermittent stimulation can cause neural processes that mimic the effects of colored stimuli.