Recognition and Perception of Images. Группа авторов
[Pepperell, 2019].
Figure 1.1.2 Example of three groups of stimuli tested in study (Original, column (a); Style, column (b); Color, column (c) [Maglione et al., 2017]).
It has been found that different regions of the brain including not only the frontal but also the motional and parietal cortical layers take part in the valuation of perceivable stimuli. It is necessary to admit that the prefrontal dorsolateral brain cortex is selectively activated by the only stimuli considered to be attractive. At the same time, the prefrontal activity is generally activated during the valuation of both pleasant and unpleasant stimuli. The value of research is that the neuroelectric visualization may be used for receiving useful information relating to the evolution of the aesthetic view of people who perceive the images from simple stimuli to the works of art.
The work of [Tikhomirov et al., 2018] is dedicated to the study of agnosia of visual objects to determine the pathologies of the brain. The visual agnosia has arisen in the case of damage of brain cortex structure responsible for the analysis and synthesis of information thus leading to the violation of the perceptual process and recognition of visual stimuli. The contemporary views about the neuroanatomical and neurophysiological basis of the visual process are described. The medical cases of visual objects agnosia and peculiarities of neuropsycological diagnostics and post-hospital rehabilitation of patients are presented.
The visual objects of different origin such as object images, geometric figures, letters, words and faces with various emotional expressions were used for testing. The basic test models were based on the modified methods of Wundt (Figure 1.1.3(a)), Stroop’s method (Figure 1.1.3(b)) and Gottschaldt figures (Figure 1.1.3(c)). The error types, response duration and detection time were evaluated; the recommendations on the diagnostics of visual agnosia in the clinical practice were worked out.
Furthermore, we’ll analyze some main concepts relating to the biological evolution of organs of visual sensing, the structural features of the human eye as well as the process of processing and perception of visual information by the brain.
Figure 1.1.3 Examples of interactive realization of basic test models: (a) Wundt’s method; (b) interference test by Stroop’s method; (c) test by Gottschaldt figures [Tikhomirov et al., 2018].
1.1.2 Light Perception
Photosensitive tissue is present in the simplest organisms. The reaction to light is fundamentally different from the formation of a visual image. The visual structures of the simplest organisms only accumulate light using a photosensitive pigment [Shiffman, 2008]. An eye capable of forming an image appeared in the later stages of evolution. The complex eye of arthropods consists of a bundle of conical elements (ommatidium, Greek – small eye, Figure 1.1.4) containing a lens and a photosensitive pigment [Website istockphoto, 2020]. Each ommatidium registers the incident light from the opposite side, resulting in an image consisting of individual signals. The resulting image is therefore grainy. Such a complex eye is effective in detecting minor changes in the visual field. According to this principle, a complex eye of a fly acts, which is not so easy to catch.
A compound eye is effective for detecting closely spaced objects. The eyes of vertebrates, in contrast to the complex eyes, are perfectly visible at a great distance. The eye of each biological species is maximally adapted to the conditions of its natural habitat and way of life activity.
1.1.3 Vertebrate Eye Anatomy
Anatomically, the eyes of all vertebrates have a similar structure. From fish to mammals, the eyes of all vertebrates have a photosensitive layer, called the retina, and a lens to focus the image on the retina. Figure 1.1.5 presents a vertical section of the human eye.
Figure 1.1.4 Structure of the compound eye of a fly.
The eyeball is located in the deepening of the skull, and has a spherical shape with a diameter of about 20 mm. Outside the eyeball is covered with sclera, a white opaque sheath about 1 mm thick. On the front surface of the eye, the sclera enters the transparent membrane – the cornea. The curved surface of the cornea provides the necessary refractive index (refraction) in the optical system of the eye. It has no blood vessels, it receives nutrients from the capillaries and liquids surrounding it. Light rays are refracted on the cornea and focused by a lens on the retina, located on the back of the eyeball. The vascular membrane of the eye is associated with the sclera, has a thickness of 0.2 mm, and consists of blood vessels that feed the eyes.
The anterior part of the choroid is a colored concentric disc called the iris. From a biological point of view, the iris contains a landscape filled with rings, dashes, specks; each person has more than 200 individual distinguishing features. The iris is a disc-shaped, colored membrane consisting of two smooth muscles, located between the cornea and the lens [Fershild, 2004].
Pigmentation of the iris is determined by the concentration of melanin inside the iris. The main function of the iris is to regulate the amount of light that enters the eye. In low light, the iris contracts, and the pupil increases in the form of a round black hole. In bright light, the reverse process occurs; the iris is stretched, and the pupils are narrowed. The change of the pupil is controlled by two oppositely directed iris muscles – the sphincter and the dilator of the pupil. In an adult, the diameter of the pupil varies from 2 to 9 mm; this leads to a change in the area of the pupil of more than 20 times.
Figure 1.1.5 Vertical section of the human eye.
Usually the pupil responds to changes in illumination reflexively; bright irritating light causes Witt’s reflex (described by physiologist Robert Witt in 1751). Witt’s reflex is used to diagnose diseases of the central nervous system, as well as to determine signs of life in a person during rescue operations.
The human pupil is round, but the pupils of some species may have a different shape. The pupils of the cat’s eyes are in the form of a vertical slit, and nocturnal animals (including crocodiles) have such pupils. Nocturnal animals also have a retinal layer, called tapetum (lat. tapete – carpet). It reflects part of the light that enters the eye. It is the reflection of light from the tapetum that causes the eyes to “glow” at night. In the dark, we notice well the “glowing”