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    Visual Perception: Insights into Computational Visual Processing
    Visual Perception: Insights into Computational Visual Processing
    Visual Perception: Insights into Computational Visual Processing
    Ebook115 pages1 hourComputer Vision

    Visual Perception: Insights into Computational Visual Processing

    By Fouad Sabry

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    About this ebook

    What is Visual Perception


    Visual perception is the capacity to interpret the environment around oneself through the use of photopic vision, color vision, scotopic vision, and mesopic vision. This is accomplished by utilizing light in the visible spectrum that is reflected by things which are present in the environment. However, this is not the same as visual acuity, which is the degree to which a person is able to see well. Even if a person seems to have perfect vision, they may nevertheless struggle with the processing of their visual perceptual information.


    How you will benefit


    (I) Insights, and validations about the following topics:


    Chapter 1: Visual perception


    Chapter 2: Retina


    Chapter 3: Color constancy


    Chapter 4: Color vision


    Chapter 5: Visual system


    Chapter 6: Sensory nervous system


    Chapter 7: Photoreceptor cell


    Chapter 8: Afterimage


    Chapter 9: Trichromacy


    Chapter 10: Cone cell


    (II) Answering the public top questions about visual perception.


    (III) Real world examples for the usage of visual perception in many fields.


    Who this book is for


    Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of Visual Perception.

    LanguageEnglish
    PublisherOne Billion Knowledgeable
    Release dateApr 30, 2024
    Visual Perception: Insights into Computational Visual Processing

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      Book preview

      Visual Perception - Fouad Sabry

      Chapter 1: Visual perception

      Photoptic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision) use light in the visible spectrum reflected from objects to create an interpretation of the surrounding environment. Contrast this with a statement like I have 20/20 vision, which describes how sharply an individual's eyes see. Even with perfect eyesight, some people struggle with the processing of visual information.

      Vision, sight, and eyesight are all names for the ensuing sense (adjectives visual, optical, and ocular, respectively). Many fields of study, including linguistics, psychology, cognitive science, neurology, and molecular biology, have focused on the numerous physiological components involved in vision, which are together referred to as the visual system.

      The cornea acts as a window for light to enter the eye, and the lens focuses that light onto the retina, a light-sensitive membrane in the back of the eye, where it may be detected. The retina acts as a transducer, transforming visual cues into neural impulses. Rods and cones, two types of specialized photoreceptor cells in the retina, perform this transduction by sensing light and reacting with nerve impulses. The optic nerve carries these impulses from the retina to the brain's central ganglia. The information is sent to the visual cortex from the lateral geniculate nucleus. There is also a direct pathway for retinal signals to reach the superior colliculus. The visual association cortex has been described in recent years as being split into a dorsal and a ventral functional circuit. The two streams hypothesis describes this speculation.

      Human eyes are thought to be able to detect electromagnetic radiation with wavelengths between 370 and 730 nanometers (0.00000037 and 0.00000073 meters).

      The main issue with vision is that what individuals actually perceive is not an exact representation of what is happening in their retinas (i.e., the image on the retina). As a result, researchers in the field of perception have had a hard time articulating how exactly visual processing results in the world as we experience it.

      Two main ancient Greek schools provide a rudimentary explanation of vision's mechanism.

      The earliest of them was the emission theory of vision, which proposed that perception takes place when rays from the eyes are reflected back to the brain after being intercepted by visible objects. Direct vision required rays from the eyes to return to the item they were observing. However, a refracted image may also be viewed by means of rays, which left the eyes, traveled through the air, and eventually fell on the visible object observed as a result of the rays' motion. Scholars who admired the works of Euclid and Ptolemy in the field of optics advocated for this hypothesis.

      The second school of thought held that what we perceive is a representation of the item itself that enters our eyes. Aristotle was the movement's primary proponent (De Sensu), Alhazen (965 - c. 1040) conducted extensive tests on vision, built upon Ptolemy's research on binocular vision, and provided insightful commentary on Galen's anatomical writings.

      Modern studies of vision are generally attributed to Hermann von Helmholtz. Based on his research, Helmholtz concluded that the human eye cannot produce a sharp image. It looked impossible to observe clearly due to a lack of data. Thus, he arrived to the conclusion that vision must be the consequence of unconscious inference, a word he first used in 1867. He hypothesized that memory and experience allowed the brain to draw conclusions from little information.

      To make an inference, one must have had exposure to the real world.

      Typical presumptions that people make based on what they've seen are:

      Light is generated from above; Observing things from below is uncommon; The normal (and preferred) viewing angle for faces; The visibility of further away items can be obscured by those closer to the viewer, but not vice versa; and

      It's common for humans, or foreground items, to have rounded corners.

      Learning what sorts of assumptions the visual system makes through studying visual illusions (situations where the inference process fails).

      So-called Bayesian studies of visual perception have lately revitalized yet another form of unconscious inference hypothesis (based on probabilities). Another related and more recent theory that attempts to explain sight without resorting to Bayesian formalisms is known as the wholly empirical theory of perception..

      Many of the questions that vision scientists today are attempting to answer were first posed by Gestalt psychologists in the 1930s and 1940s.

      The study of how humans perceive visual components as organized patterns or wholes, rather than a collection of disparate elements, has been driven by the Gestalt Laws of Organization. The German word Gestalt can be roughly translated as complete or emerging structure and configuration or pattern. This hypothesis proposes that the visual system's instinctive categorization of items into patterns is determined by the following eight criteria: Good Gestalt (a regular, basic, and ordered pattern) and Prior Experience, as well as Proximity, Similarity, Closure, Symmetry, Common Fate (i.e. common motion), and Continuity.

      In the 1960s, technological advancements made it possible to continuously record eye movement while reading, What might happen within the first two seconds of a visual inspection is depicted to the right. While the man's boots are in sharp focus, the blurred background represents the viewer's peripheral vision (just because they are very near the starting fixation and have a reasonable contrast). The purpose of eye movement is attentional selection, which is the process by which the brain chooses which of many possible visual inputs to examine in greater detail.

      The subsequent obsessions will quickly switch faces. They may even make cross-face comparisons possible.

      It's safe to say that the icon's visage makes for a highly appealing search symbol when viewed from a distance. The foveal field of vision supplements the peripheral field of view with additional information.

      It's important to differentiate between the several forms of eye movements, including fixational (microsaccades, ocular drift, and tremor), vergence, saccadic, and pursuit. Fixations are relatively stationary focusing points. However, the position of the gaze always changes somewhat. Microsaccades, or extremely brief shifts in fixation, are used to counteract these drifts. The ability to perform vergence movements requires coordination between the two eyes so that a picture lands in the same spot on both retinas. One sharp picture is produced as a result. Rapidly scanning a scene or an image requires a certain sort of eye movement known as saccadic motions, in which the eyes rapidly shift from one location to another. Finally, pursuit movement is a type of smooth eye movement utilized to track moving targets.

      There's a lot of data suggesting that different systems are responsible for face and object recognition. Patients with prosopagnosia, on

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