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Fechner Color
The Fechner color effect is an illusion of color seen when looking at certain rapidly changing or moving black-and-white patterns. They are also called pattern induced flicker colors (PIFCs). The effect is most commonly demonstrated with a device known as Benham's top (also called Benham's disk). When the top is spun, arcs of pale color are visible at different places on the disk that forms its upper surface. The effect can also be seen in stroboscopic lights when flashes are set at certain critical speeds. Rotating fan blades, particularly aluminum ones, can also demonstrate the effect; as the fan accelerates or decelerates, the colors appear, drift, change and disappear. The stable running speed of the fan does not (normally) produce colors, suggesting that it is not an interference effect with the frequency of the illumination flicker. The effect was noted by Gustav Fechner and Hermann von Helmholtz and propagated to English-speakers through Charles Benham's invention of his t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illusion
An illusion is a distortion of the senses, which can reveal how the mind normally organizes and interprets sensory stimulation. Although illusions distort the human perception of reality, they are generally shared by most people. Illusions may occur with any of the human senses, but visual illusions ( optical illusions) are the best-known and understood. The emphasis on visual illusions occurs because vision often dominates the other senses. For example, individuals watching a ventriloquist will perceive the voice is coming from the dummy since they are able to see the dummy mouth the words. Some illusions are based on general assumptions the brain makes during perception. These assumptions are made using organizational principles (e.g., Gestalt theory), an individual's capacity for depth perception and motion perception, and perceptual constancy. Other illusions occur because of biological sensory structures within the human body or conditions outside the body within one's phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Receptors
Cone cells, or cones, are photoreceptor cells in the retinas of vertebrate eyes including the human eye. They respond differently to light of different wavelengths, and the combination of their responses is responsible for color vision. Cones function best in relatively bright light, called the photopic region, as opposed to rod cells, which work better in dim light, or the scotopic region. Cone cells are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. Conversely, they are absent from the optic disc, contributing to the blind spot. There are about six to seven million cones in a human eye (vs ~92 million rods), with the highest concentration being towards the macula. Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), but allow the perception of color. They are also able to perceive finer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Bach (vision Scientist)
Michael Bach (born 10 April 1950) is a German scientist who researches ophthalmology, clinical electroencephalography, clinical electroretinography, visual acuity testing, and visual perception. Bach is the creator of website ''Optical Illusions & Visual Phenomena'', which received over two million hits a day in 2005. Life and work Bach was born in Berlin on 10 April 1950. In 1956 he moved with his family to Dortmund, where he attended school. From 1970 to 1972, Bach completed an undergraduate degree in physics at Ruhr University Bochum, then moved to the University of Freiburg, where he studied for a Master's degree in physics. In 1975, he began a part-time position running an electronics workshop in the Department of Psychology, then began as a full-time research assistant in the Department of Neurology in 1978. Bach was awarded his Master's in physics in 1977 and his PhD, also in physics, in 1981, on the visual system. In 1981 he moved into a full-time position in the Dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newton Disc
The Newton disc, also known as the Disappearing Colour Disc, is a well-known physics experiment with a rotating disc with segments in different colors (usually Newton's primary colors: red, orange, yellow, green, blue, indigo, and violet or ROYGBIV) appearing as white (or off-white or gray) when it spins very fast. This type of mix of light stimuli is called temporal optical mixing, a version of additive-averaging mixing. The concept that human visual perception cannot distinguish details of high-speed movements is popularly known as persistence of vision. The disc is named after Isaac Newton. Although he published a circular diagram with segments for the primary colors that he had discovered, it is uncertain whether he actually ever used a spinning disc to demonstrate the principles of light. Transparent variations for magic lantern projection have been produced. History Around 165 CE, Ptolemy described in his book ''Optics'' a rotating potter's wheel with different colors on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Neuritis
Optic neuritis describes any condition that causes inflammation of the optic nerve; it may be associated with demyelinating diseases, or infectious or inflammatory processes. It is also known as optic papillitis (when the head of the optic nerve is involved), neuroretinitis (when there is a combined involvement of the optic disc and surrounding retina in the macular area) and retrobulbar neuritis (when the posterior part of the nerve is involved). Prelaminar optic neuritis describes involvement of the non-myelinated axons in the retina. It is most often associated with multiple sclerosis, and it may lead to complete or partial loss of vision in one or both eyes. Other causes include: # Leber's hereditary optic neuropathy # Parainfectious optic neuritis (associated with viral infections such as measles, mumps, chickenpox, whooping cough and glandular fever) # Infectious optic neuritis (sinus related or associated with cat-scratch fever, tuberculosis, Lyme disease and crypt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opponent Process
The opponent process is a color theory that states that the human visual system interprets information about color by processing signals from photoreceptor cells in an antagonistic manner. The opponent-process theory suggests that there are three opponent channels, each comprising an opposing color pair: red versus green, blue versus yellow, and black versus white (luminance). The theory was first proposed in 1892 by the German physiologist Ewald Hering. Color theory Complementary colors When staring at a bright color for awhile (e.g. red), then looking away at a white field, an afterimage is perceived, such that the original color will evoke its complementary color (green, in the case of red input). When complementary colors are combined or mixed, they "cancel each other out" and become neutral (white or gray). That is, complementary colors are never perceived as a mixture; there is no "greenish red" or "yellowish blue", despite claims to the contrary. The strongest color con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Visual Cortex
The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and then reaches the visual cortex. The area of the visual cortex that receives the sensory input from the lateral geniculate nucleus is the primary visual cortex, also known as visual area 1 ( V1), Brodmann area 17, or the striate cortex. The extrastriate areas consist of visual areas 2, 3, 4, and 5 (also known as V2, V3, V4, and V5, or Brodmann area 18 and all Brodmann area 19). Both hemispheres of the brain include a visual cortex; the visual cortex in the left hemisphere receives signals from the right visual field, and the visual cortex in the right hemisphere receives signals from the left visual field. Introduction The primary visual cortex (V1) is located in and around the calcarine fissure in the occipital lobe. Each hemisphere's V1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retina
The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception. The retina serves a function which is in many ways analogous to that of the film or image sensor in a camera. The neural retina consists of several layers of neurons interconnected by synapses and is supported by an outer layer of pigmented epithelial cells. The primary light-sensing cells in the retina are the photoreceptor cells, which are of two types: rods and cones. Rods function mainly in dim light and provide monochromatic vision. Cones function in well-lit conditions and are responsible for the perception of colour through the use of a range of opsins, as well as high-acuity vision used for task ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system, which in turn result from physical or chemical stimulation of the sensory system.Goldstein (2009) pp. 5–7 Vision involves light striking the retina of the eye; smell is mediated by odor molecules; and hearing involves pressure waves. Perception is not only the passive receipt of these signals, but it is also shaped by the recipient's learning, memory, expectation, and attention. Gregory, Richard. "Perception" in Gregory, Zangwill (1987) pp. 598–601. Sensory input is a process that transforms this low-level information to higher-level information (e.g., extracts shapes for object recognition). The process that follows connects a person's concepts and expectations (or knowledge), restorative and selective mechanisms (such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color
Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are associated with objects or materials based on their physical properties such as light absorption, reflection, or emission spectra. By defining a color space, colors can be identified numerically by their coordinates. Because perception of color stems from the varying spectral sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance. Color science includes the perception of color by the eye and brain, the origin of color in materials, color theory in art, and the physics of electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florence Bagley
Florence Winger Bagley (January 7, 1874 – 1952) was a 19th-century American psychologist. Bagley's work focused on the research of Fechner's color rings and color aesthetics. She was listed in the first biographical compilation of American scientists. Early life and education Florence Bagley was born in Clay Lick, Pennsylvania. She was the daughter of Margaret (née Irwin) and Joseph W Winger. Bagley studied at the University of Nebraska and received her A.B. degree in 1895 and A.M. degree in 1898. She then moved to Cornell University in 1898, again as a Fellow in Psychology, holding the Susan Linn Sage Fellowship in Philosophy and Ethics. She completed her doctoral research in 1901 but did not complete writing her dissertation. However, her work was published under the guidance of her supervisor, Edward B. Titchener. She was recognized with membership in Sigma XI from Cornell and was a member of Kappa Kappa Gamma. Research Bagley's research in the field of Psychology occurre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Benham
Charles Edwin Benham JP (; 15 April 1860 in Colchester, Essex, England – 1 April 1929, also in Colchester) was a journalist who edited for many years the ''Essex County Standard,'' a published author of works such as ''Essex Ballads,'' and an amateur scientist-cum-inventor, which led him to create Benham's top, which was named after him. Known life and career Born on 15 April 1860 into a family of newspaper proprietors, Benham was educated at Colchester Royal Grammar School but did not attend university. He later returned to the school to become President of the Old Colcestrian Society for old boys of the school. Living in Colchester for all but a handful of years of his life spent with Mebrose printers in Derby - and, in turn, writing about it in many of his books - he helped edit the family-controlled paper the ''Essex County Standard'' jointly with his brother William Gurney Benham from 1892 until his death in 1929, which was described as "sudden and unexpected," from an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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