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Crowding Out Effect
Crowding (or visual crowding) is a perceptual phenomenon where the recognition of objects presented away from the fovea is impaired by the presence of other neighbouring objects (sometimes called "flankers"). It has been suggested that crowding occurs due to mandatory integration of the crowded objects by a texture-processing neural mechanism, but there are several competing theories about the underlying mechanisms. It is considered a kind of grouping since it is "a form of integration over space as target features are spuriously combined with flanker features." Crowding has long been thought to be predominantly a characteristic of peripheral vision. Yet, while it is indeed particularly prominent there, it is present in the whole of the visual field, with only its spatial extent varying (governed by Bouma's law; see below). In particular, crowding is of utmost importance in foveal vision, overriding the importance of visual acuity in pattern recognition and reading where crowdi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Angle
Visual angle is the angle a viewed object subtends at the eye, usually stated in degrees of arc. It also is called the object's angular size. The diagram on the right shows an observer's eye looking at a frontal extent (the vertical arrow) that has a linear size S, located in the distance D from point O. For present purposes, point O can represent the eye's nodal points at about the center of the lens, and also represent the center of the eye's entrance pupil that is only a few millimeters in front of the lens. The three lines from object endpoint A heading toward the eye indicate the bundle of light rays that pass through the cornea, pupil and lens to form an optical image of endpoint A on the retina at point a. The central line of the bundle represents the chief ray. The same holds for object point B and its retinal image at b. The visual angle V is the angle between the chief rays of A and B. Measuring and computing The visual angle V can be measured directly usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Perception
Visual perception is the ability to detect light and use it to form an image of the surrounding Biophysical environment, environment. Photodetection without image formation is classified as ''light sensing''. In most vertebrates, visual perception can be enabled by photopic vision (daytime vision) or scotopic vision (night vision), with most vertebrates having both. Visual perception detects light (photons) in the visible spectrum reflected by objects in the environment or emitted by light sources. The light, visible range of light is defined by what is readily perceptible to humans, though the visual perception of non-humans often extends beyond the visual spectrum. 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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object Recognition And Categorization
Object recognition – technology in the field of computer vision for finding and identifying objects in an image or video sequence. Humans recognize a multitude of objects in images with little effort, despite the fact that the image of the objects may vary somewhat in different view points, in many different sizes and scales or even when they are translated or rotated. Objects can even be recognized when they are partially obstructed from view. This task is still a challenge for computer vision systems. Many approaches to the task have been implemented over multiple decades. Approaches based on CAD-like object models * Edge detection * Primal sketch * Marr, Mohan and Nevatia * Lowe * Olivier Faugeras Recognition by parts * Generalized cylinders (Thomas Binford) * Geon (psychology), Geons (Irving Biederman) * Dickinson, Forsyth and Ponce Appearance-based methods * Use example images (called templates or exemplars) of the objects to perform recognition * Objects ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniel Kahneman
Daniel Kahneman (; ; March 5, 1934 – March 27, 2024) was an Israeli-American psychologist best known for his work on the psychology of judgment and decision-making as well as behavioral economics, for which he was awarded the 2002 Nobel Memorial Prize in Economic Sciences together with Vernon L. Smith. Kahneman's published empirical findings challenge the assumption of human rationality prevailing in modern economic theory. Kahneman became known as the "grandfather of behavioral economics." With Amos Tversky and others, Kahneman established a cognitive basis for common human errors that arise from heuristics and biases, and developed prospect theory. In 2011, Kahneman was named by ''Foreign Policy'' magazine in its list of top global thinkers. In the same year, his book '' Thinking, Fast and Slow'', which summarizes much of his research, was published and became a best seller. In 2015, ''The Economist'' listed him as the seventh most influential economist in the world. Kah ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Chart
__NOTOC__ An eye chart is a chart used to measure visual acuity comprising lines of optotypes in ranges of sizes. Optotypes are the letters or symbols shown on an eye chart. Eye charts are often used by health care professionals, such as optometrists, physicians and nurses, to screen persons for vision impairment. Ophthalmology, Ophthalmologists, physicians who specialize in the eye, also use eye charts to monitor the visual acuity of their patients in response to various therapies such as Eye drop, medications or Eye surgery, surgery. The chart is placed at a standardized distance away from the person whose vision is being tested. The person then attempts to identify the optotypes on the chart, starting with the larger ones and continuing with progressively smaller ones until the person cannot identify the optotypes. The size of the smallest optotypes that can be reliably identified is considered the person's visual acuity. The Snellen chart is the most widely used. Alternative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Friedrich Richard Förster
Carl Friedrich Richard Förster (15 November 1825 – 7 July 1902) was a German ophthalmologist born in the town of Lissa (today Leszno, Poland). He received his medical doctorate in 1849, and for most of his career was associated with the University of Breslau. Two of his assistants at Breslau were Hermann Wilbrand (1851–1935) and Hermann Rudolph Aubert (1826–1892). Förster is remembered for conducting tests of visual acuity, and for his investigations of indirect vision (peripheral vision) and visual performance across the visual field together with Hermann Aubert. The linear variation of visual performance that they described is sometimes referred to as the Aubert-Foerster law. From Förster's research, the eponymous terms of "Förster perimeter" and "Förster's shift" are derived. A Förster perimeter was an instrument used to measure an individual's field of vision. He also devised a specialized photometer to determine the smallest amount of light that will permit an ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermann Rudolph Aubert
Hermann Rudolph Aubert (November 23, 1826 – February 12, 1892) was a German physiologist born in Frankfurt (Oder), Frankfurt. In 1850 he obtained his medical doctorate, afterwards serving as privat-docent of physiology at Breslau (1854). In 1862 he became an associate professor, later being appointed professor of physiology at the University of Rostock (1865). Aubert is known for his research involving psychophysics, including the way an observer perceives pattern, movement and orientation. He conducted several experiments involving the phenomenon of Adaptation (eye), dark adaptation; namely the eye's ability to regain its sensitivity in the dark after it had been exposed to bright lights. With ophthalmologist Carl Friedrich Richard Foerster, Richard Förster (1825–1902), he performed a series of tests on vision outside the fixation (visual), point of fixation, which they referred to as indirect vision. Their findings were published in a treatise called ''Beiträge zur Kenntn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Jurin
James Jurin (baptised 15 December 168429 March 1750) was an English scientist and physician, particularly remembered for his early work in capillary action and in the epidemiology of smallpox vaccination. He was a staunch proponent of the work of Sir Isaac Newton and often used his gift for satire in Newton's defence. In 1716 he was present—along with Newton, Robert Smith, William Whiston, and Edmund Halley—when Martin Folkes proposed the black Jamaican Francis Williams for fellowship of the Royal Society. Early life Jurin's father was John Jurin, a London dyer. His mother was John's wife Dorcas Cotesworth. He was educated at Christ's Hospital where he won a scholarship to Trinity College, Cambridge, graduating BA in 1705, and being elected fellow the following year. Becoming the ''protégé'' of the master of Trinity, Richard Bentley, Jurin became tutor to Mordecai Cary, travelling with him internationally. Jurin achieved his MA in 1709 and became headteacher of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ibn Al-Haytham
Ḥasan Ibn al-Haytham (Latinization of names, Latinized as Alhazen; ; full name ; ) was a medieval Mathematics in medieval Islam, mathematician, Astronomy in the medieval Islamic world, astronomer, and Physics in the medieval Islamic world, physicist of the Islamic Golden Age from present-day Iraq.For the description of his main fields, see e.g. ("He is one of the principal Arab mathematicians and, without any doubt, the best physicist.") , ("Ibn al-Ḥaytam was an eminent eleventh-century Arab optician, geometer, arithmetician, algebraist, astronomer, and engineer."), ("Ibn al-Haytham (d. 1039), known in the West as Alhazan, was a leading Arab mathematician, astronomer, and physicist. His optical compendium, Kitab al-Manazir, is the greatest medieval work on optics.") Referred to as "the father of modern optics", he made significant contributions to the principles of optics and visual perception in particular. His most influential work is titled ''Book of Optics, Kit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ricco's Law
Riccò's law, discovered by astronomer Annibale Riccò, is one of several laws that describe a human's ability to visually detect targets on a uniform background. It says that for visual targets below a certain size, threshold visibility depends on the area of the target, and hence on the total light received. The "certain size" (called the "critical visual angle"), is small in daylight conditions, larger in low light levels. The law is of special significance in visual astronomy, since it concerns the ability to distinguish between faint point sources (e.g. stars) and small, faint extended objects (Deep-sky object, "DSOs"). Derivation Suppose that an achromatic target of angular area A is viewed against a uniform background luminance B (e.g. a disc of white light is projected on a white screen, or a nebula is seen through a telescope). For the target to be visible at all, there must be sufficient luminance Contrast (vision), contrast; i.e. the target must be brighter (or darker) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weber–Fechner Law
The Weber–Fechner laws are two related scientific law, scientific laws in the field of psychophysics, known as Weber's law and Fechner's law. Both relate to human perception, more specifically the relation between the actual change in a physical Stimulus (physiology), stimulus and the perceived change. This includes stimuli to all senses: vision, hearing, taste, touch, and smell. Ernst Heinrich Weber states that "the minimum increase of stimulus which will produce a perceptible increase of sensation is proportionality (mathematics), proportional to the pre-existent stimulus," while Gustav Fechner's law is an inference from Weber's law (with additional assumptions) which states that the intensity of our sensation increases as the logarithm of an increase in energy rather than as rapidly as the increase. History and formulation of the laws Both Weber's law and Fechner's law were formulated by Gustav Fechner, Gustav Theodor Fechner (1801–1887). They were first published in 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
