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Illusory Contours
Illusory contours or subjective contours are visual illusions that evoke the perception of an edge without a luminance or color change across that edge. Illusory brightness and depth ordering often accompany illusory contours. Friedrich Schumann is often credited with the discovery of illusory contours around the beginning of the 20th century, but they are present in art dating to the Middle Ages. Gaetano Kanizsa’s 1976 ''Scientific American'' paper marked the resurgence of interest in illusory contours for vision scientists. Common types of illusory contours Kanizsa figures Perhaps the most famous example of an illusory contour is the Pac-Man configuration popularized by Gaetano Kanizsa. Kanizsa figures trigger the percept of an illusory contour by aligning Pac-Man-shaped inducers in the visual field such that the edges form a shape. Although not explicitly part of the image, Kanizsa figures evoke the percept of a shape, defined by a sharp illusory contour. Typically, the shap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kanizsa Triangle
Illusory contours or subjective contours are visual illusions that evoke the perception of an edge without a luminance or color change across that edge. Illusory brightness and depth ordering often accompany illusory contours. Friedrich Schumann is often credited with the discovery of illusory contours around the beginning of the 20th century, but they are present in art dating to the Middle Ages. Gaetano Kanizsa’s 1976 ''Scientific American'' paper marked the resurgence of interest in illusory contours for vision scientists. Common types of illusory contours Kanizsa figures Perhaps the most famous example of an illusory contour is the Pac-Man configuration popularized by Gaetano Kanizsa. Kanizsa figures trigger the percept of an illusory contour by aligning Pac-Man-shaped inducers in the visual field such that the edges form a shape. Although not explicitly part of the image, Kanizsa figures evoke the percept of a shape, defined by a sharp illusory contour. Typically, the shap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neon Color Circle
Neon is a chemical element with the symbol Ne and atomic number 10. It is a noble gas. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. It was discovered (along with krypton and xenon) in 1898 as one of the three residual rare inert elements remaining in dry air, after nitrogen, oxygen, argon and carbon dioxide were removed. Neon was the second of these three rare gases to be discovered and was immediately recognized as a new element from its bright red emission spectrum. The name neon is derived from the Greek word, , neuter singular form of (), meaning 'new'. Neon is chemically inert, and no uncharged neon compounds are known. The compounds of neon currently known include ionic molecules, molecules held together by van der Waals forces and clathrates. During cosmic nucleogenesis of the elements, large amounts of neon are built up from the alpha-capture fusion process in stars. Although neon is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Receptive Field
The receptive field, or sensory space, is a delimited medium where some physiological stimuli can evoke a sensory neuronal response in specific organisms. Complexity of the receptive field ranges from the unidimensional chemical structure of odorants to the multidimensional spacetime of human visual field, through the bidimensional skin surface, being a receptive field for touch perception. Receptive fields can positively or negatively alter the membrane potential with or without affecting the rate of action potentials. A sensory space can be dependent of an animal's location. For a particular sound wave traveling in an appropriate transmission medium, by means of sound localization, an auditory space would amount to a reference system that continuously shifts as the animal moves (taking into consideration the space inside the ears as well). Conversely, receptive fields can be largely independent of the animal's location, as in the case of place cells. A sensory space can also m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phantom Contour
A phantom contour is a type of illusory contour. Most illusory contours are seen in still images, such as the Kanizsa triangle and the Ehrenstein illusion. A phantom contour, however, is perceived in the presence of moving or flickering images with contrast reversal.Kiely, P. M., Crewther, S. G., & Crewther, D. P. (2007). Threshold recognition of phantom-contour objects requires contrast velocity. Perception & Psychophysics, 69, 1035-1039. The rapid, continuous alternation between opposing, but correlated, adjacent images creates the perception of a contour that is not physically present in the still images. Quaid et al. have also authored a PhD thesis on the phantom contour illusion and its spatiotemporal limits (University of Waterloo) which maps out limits and proposes mechanisms for its perception centering around magnocellularly driven visual area MT (see also Quaid et al., 2005 on www.pubmed.com). Example One example of this illusion involves stimuli consisting of two sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negative Space
Negative space, in art, is the empty space around and between the subject(s) of an image. Negative space may be most evident when the space around a subject, not the subject itself, forms an interesting or artistically relevant shape, and such space occasionally is used to artistic effect as the "real" subject of an image. Overview The use of negative space is a key element of artistic composition. The Japanese word " ma" is sometimes used for this concept, for example in garden design. In a composition, the positive space has the more visual weight while the surrounding space - that is less visually important is seen as the negative space. In a two-tone, black-and-white image, a subject is normally depicted in black and the space around it is left blank (white), thereby forming a silhouette of the subject. Reversing the tones so that the space around the subject is printed black and the subject itself is left blank, however, causes the negative space to be apparent as it fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestalt Psychology
Gestalt-psychology, gestaltism, or configurationism is a school of psychology that emerged in the early twentieth century in Austria and Germany as a theory of perception that was a rejection of basic principles of Wilhelm Wundt's and Edward Titchener's elementalist and structuralist psychology.Mather, George (2006) Foundations of Perception, Psychology Pressch.1 p.32 As used in Gestalt psychology, the German word ''Gestalt'' ( , ; meaning "form") is interpreted as "pattern" or "configuration". Gestalt psychologists emphasize that organisms perceive entire patterns or configurations, not merely individual components. The view is sometimes summarized using the adage, "the whole is more than the sum of its parts." Gestalt psychology was founded on works by Max Wertheimer, Wolfgang Köhler, and Kurt Koffka. Origin and history Max Wertheimer (1880–1943), Kurt Koffka (1886–1941), and Wolfgang Köhler (1887-1967) founded Gestalt psychology in the early 20th century. The domi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filling-in
In vision, filling-in phenomena are those responsible for the completion of missing information across the physiological blind spot, and across natural and artificial scotomata. There is also evidence for similar mechanisms of completion in normal visual analysis. Classical demonstrations of perceptual filling-in involve filling in at the blind spot in monocular vision, and images stabilized on the retina either by means of special lenses, or under certain conditions of steady fixation. For example, naturally in monocular vision at the physiological blind spot, the percept is not a hole in the visual field, but the content is “filled-in” based on information from the surrounding visual field. When a textured stimulus is presented centered on but extending beyond the region of the blind spot, a continuous texture is perceived. This partially inferred percept is paradoxically considered more reliable than a percept based on external input. (Ehinger ''et al.'' 2017). A second ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autostereogram
An autostereogram is a two-dimensional (2D) image that can create the optical illusion of a three-dimensional (3D) scene. Autostereograms use only one image to accomplish the effect while normal stereograms require two. The 3D scene in an autostereogram is often unrecognizable until it is viewed properly, unlike typical stereograms. Viewing any kind of stereogram properly may cause the viewer to experience vergence-accommodation conflict. The optical illusion of an autostereogram is one of depth perception and involves stereopsis: depth perception arising from the different perspective each eye has of a three-dimensional scene, called binocular parallax. Individuals with disordered binocular vision and who cannot perceive depth may require a wiggle stereogram to achieve a similar effect. The simplest type of autostereogram consists of a horizontally repeating pattern with small changes throughout that looks like wallpaper. When viewed with proper vergence, the repeating p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amodal Perception
Amodal perception is the perception of the whole of a physical structure when only parts of it affect the sensory receptors. For example, a table will be perceived as a complete volumetric structure even if only part of it—the facing surface—projects to the retina; it is perceived as possessing internal volume and hidden rear surfaces despite the fact that only the near surfaces are exposed to view. Similarly, the world around us is perceived as a surrounding plenum, even though only part of it is in view at any time. Another much quoted example is that of the "dog behind a picket fence" in which a long narrow object (the dog) is partially occluded by fence-posts in front of it, but is nevertheless perceived as a single continuous object. Albert Bregman noted an auditory analogue of this phenomenon: when a melody is interrupted by bursts of white noise, it is nonetheless heard as a single melody continuing "behind" the bursts of noise. Formulation of the theory is credited to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Face Recognition
A facial recognition system is a technology capable of matching a human face from a digital image or a video frame against a database of faces. Such a system is typically employed to authenticate users through ID verification services, and works by pinpointing and measuring facial features from a given image. Development began on similar systems in the 1960s, beginning as a form of computer application. Since their inception, facial recognition systems have seen wider uses in recent times on smartphones and in other forms of technology, such as robotics. Because computerized facial recognition involves the measurement of a human's physiological characteristics, facial recognition systems are categorized as biometrics. Although the accuracy of facial recognition systems as a biometric technology is lower than iris recognition and fingerprint recognition, it is widely adopted due to its contactless process. Facial recognition systems have been deployed in advanced human–compu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edge Detection
Edge detection includes a variety of mathematical methods that aim at identifying edges, curves in a digital image at which the image brightness changes sharply or, more formally, has discontinuities. The same problem of finding discontinuities in one-dimensional signals is known as ''step detection'' and the problem of finding signal discontinuities over time is known as ''change detection''. Edge detection is a fundamental tool in image processing, machine vision and computer vision, particularly in the areas of feature detection and feature extraction. Motivations The purpose of detecting sharp changes in image brightness is to capture important events and changes in properties of the world. It can be shown that under rather general assumptions for an image formation model, discontinuities in image brightness are likely to correspond to: * discontinuities in depth, * discontinuities in surface orientation, * changes in material properties and * variations in scene illumi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Perception
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflected by objects in the environment. This is different from visual acuity, which refers to how clearly a person sees (for example "20/20 vision"). A person can have problems with visual perceptual processing even if they have 20/20 vision. The resulting perception is also known as vision, sight, or eyesight (adjectives ''visual'', ''optical'', and ''ocular'', respectively). The various physiological components involved in vision are referred to collectively as the visual system, and are the focus of much research in linguistics, psychology, cognitive science, neuroscience, and molecular biology, collectively referred to as vision science. Visual system In humans and a number of other mammals, light enters the eye through the cornea and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
