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Visual Masking
Visual masking is a phenomenon of visual perception. It occurs when the visibility of one image, called a target, is reduced by the presence of another image, called a mask. The target might be invisible or appear to have reduced contrast or lightness. There are three different timing arrangements for masking: forward masking, backward masking, and simultaneous masking. In forward masking, the mask precedes the target. In backward masking the mask follows the target. In simultaneous masking, the mask and target are shown together. There are two different spatial arrangements for masking: pattern masking and metacontrast. Pattern masking occurs when the target and mask locations overlap. Metacontrast masking occurs when the mask does not overlap with the target location. Factors affecting visual masking Target-to-mask spatial separation Suppression can be seen in both forward and backward masking when there is pattern masking, but not when there is metacontrast. Simultaneou ... [...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] |
Contrast (vision)
Contrast is the difference in luminance or color that makes an object (or its representation in an image or display) visible against a background of different luminance or color. The human visual system is more sensitive to contrast than to absolute luminance; thus, we can perceive the world similarly despite significant changes in illumination throughout the day or across different locations. The maximum contrast of an image is termed the contrast ratio or dynamic range. In images where the contrast ratio approaches the maximum possible for the medium, there is a ''conservation of contrast''. In such cases, increasing contrast in certain parts of the image will necessarily result in a decrease in contrast elsewhere. Brightening an image increases contrast in darker areas but decreases it in brighter areas; conversely, darkening the image will have the opposite effect. Bleach bypass reduces contrast in the darkest and brightest parts of an image while enhancing luminance contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightness
Lightness is a visual perception of the luminance (L) of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a standard observer. While luminance is a linear measurement of light, lightness is a linear prediction of the human perception of that light. This distinction is meaningful because human vision's lightness perception is non-linear relative to light. Doubling the quantity of light does not result in a doubling in perceived lightness, only a modest increase. The symbol for perceptual lightness is usually either J as used in CIECAM02 or L^* as used in CIELAB and CIELUV. L^* ("Lstar") is not to be confused with L as used for luminance. In some color ordering systems such as Munsell color system, Munsell, Lightness is referenced as value. Chiaroscuro and tenebrism both take advantage of dramatic contrasts of value to heighten drama in art. Artists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, flat or inappropriate affect. Symptoms Prodrome, develop gradually and typically begin during young adulthood and rarely resolve. There is no objective diagnostic test; diagnosis is based on observed behavior, a psychiatric history that includes the person's reported experiences, and reports of others familiar with the person. For a diagnosis of schizophrenia, the described symptoms need to have been present for at least six months (according to the DSM-5) or one month (according to the ICD-11). Many people with schizophrenia have other mental disorders, especially mood disorder, mood, anxiety disorder, anxiety, and substance use disorders, substance use disorders, as well as obsessive–compulsive disorder (OCD). About 0.3% to 0.7% of peo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Inhibition
In neurobiology, lateral inhibition is the capacity of an excited neuron to reduce the activity of its neighbors. Lateral inhibition disables the spreading of action potentials An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific cell rapidly rises and falls. ... from excited neurons to neighboring neurons in the lateral direction. This creates a contrast in stimulation that allows increased sensory perception. It is also referred to as lateral antagonism and occurs primarily in visual processes, but also in Touch, tactile, Auditory system, auditory, and even olfactory processing. Cells that utilize lateral inhibition appear primarily in the cerebral cortex and thalamus and make up lateral inhibitory networks (LINs). Artificial lateral inhibition has been incorporated into artificial sensory systems, such as vision c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephen Macknik
Stephen Louis Macknik ( ; born August 9, 1968) is an American neuroscientist and science writer. He is a Professor of Ophthalmology, Neurology, and Physiology & Pharmacology at the State University of New York, Downstate Medical Center, where he directs the Laboratory of Translational Neuroscience. He directed laboratories previously at the Barrow Neurological Institute and University College London. He is best known for his studies on illusions, consciousness, attentional misdirection in stage magic, and cerebral blood flow. Macknik is a founding member of the Neural Correlate Society. He serves on the Advisory Board of ''Scientific American: Mind'', and on the Leadership Team of the Center for Emergency Management and Homeland Security at Arizona State University. Biography Early life and education Stephen Macknik was born in 1968 in Dayton, Ohio, to an astrophysicist father and physical therapist mother. He grew up in Maui, Hawaii. Macknik completed a triple-major in Psycho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Susana Martinez-Conde
Susana Martinez-Conde (born October 1, 1969) is a Spanish-American neuroscientist and science writer. She is a professor of ophthalmology, neurology, physiology, and pharmacology at the SUNY Downstate Medical Center, where she directs the Laboratory of Integrative Neuroscience. She directed laboratories previously at the Barrow Neurological Institute and University College London. Her research bridges perceptual, cognitive, and oculomotor neuroscience. She is best known for her studies on illusions, eye movements and perception, neurological disorders, and attentional misdirection in stage magic. Early life and education Susana Martinez-Conde was born in 1969 in A Coruña, Spain, to a merchant sailor father from Santander, Spain and a stay-at-home mother from Garciaz. Her maternal grandfather survived the sinking of the SS ''Castillo de Olite'' in 1939, during the Spanish Civil War. She majored in experimental psychology at the Universidad Complutense de Madrid in 1992, and ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Geniculate Nucleus
In neuroanatomy, the lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a structure in the thalamus and a key component of the mammalian visual pathway. It is a small, ovoid, Anatomical terms of location#Dorsal_and_ventral, ventral projection of the thalamus where the thalamus connects with the optic nerve. There are two LGNs, one on the left and another on the right side of the thalamus. In humans, both LGNs have six layers of neurons (grey matter) alternating with optic fibers (white matter). The LGN receives information directly from the ascending retinal ganglion cells via the optic tract and from the reticular activating system. Neurons of the LGN send their axons through the optic radiation, a direct pathway to the primary visual cortex. In addition, the LGN receives many strong feedback connections from the primary visual cortex. In humans as well as other mammals, the two strongest pathways linking the eye to the bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attentional Blink
Attentional blink (AB) is a psychological effect where people struggle to notice a second visual target in a rapid sequence if it appears 200 to 500 milliseconds after the first and is followed by distractions. For instance, in a fast stream of letters like "B, X, C, K," if "X" and "K" are targets to spot, "K" is often missed if a letter like "C" comes between them. The AB is typically measured by using rapid serial visual presentation (RSVP) tasks (tasks where items flash quickly one after another), where participants often fail to detect a second salient target if it is presented within the blink. The AB has also been observed using two backward-masked targets and auditory stimuli. The term attentional blink was first used in 1992, although the phenomenon was probably known before. Research The precise adaptive significance behind the attentional blink is unknown, but it is thought to be a product of a two-stage visual processing system attempting to allocate episodic context ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Masking
In audio signal processing, auditory masking occurs when the perception of one sound is affected by the presence of another sound.Gelfand, S.A. (2004) ''Hearing – An Introduction to Psychological and Physiological Acoustics'' 4th Ed. New York, Marcel Dekker Auditory masking in the frequency domain is known as simultaneous masking, frequency masking or spectral masking. Auditory masking in the time domain is known as temporal masking or non-simultaneous masking. Masked threshold The ''unmasked threshold'' is the quietest level of the signal which can be perceived without a masking signal present. The ''masked threshold'' is the quietest level of the signal perceived when combined with a specific masking noise. The amount of masking is the difference between the masked and unmasked thresholds. Gelfand provides a basic example.Gelfand, S.A. (2004) ''Hearing – An Introduction to Psychological and Physiological Acoustics'' 4th Ed. New York, Marcel Dekker Let us say that for a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
