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Motion perception is the process of inferring the speed and direction of objects that move in a visual scene given some visual input. While this process appears straighforward to most observers, it has proven to be a hard problem from a computational perspective, and extraordinarily difficult to explain in terms of neural processing. This article or section does not cite its references or sources. ...
The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and processes input from the senses, and initiates actions. ...
Motion perception has connections to both neurology (i.e. visual perception) and computer science. Neurology is a branch of medicine dealing with disorders of the nervous system. ...
This article or section does not cite its references or sources. ...
Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems. ...
First-order motion perception When an object (defined by a difference in luminance from its surroundings) moves, the motion can be detected by a relatively simple motion sensor designed to detect a change in luminance at one point on the retina and correlate it with a delayed change in luminance at a neighbouring point on the retina. Sensors that work this way have been referred to as Reichardt detectors (Reichardt, 1961), motion-energy sensors (Adelson & Bergen, 1985) or Elaborated Reichardt Detectors (van Santen & Sperling, 1985). These sensors detect motion by spatio-temporal correlation and are plausible models for how the visual system may detect motion. Debate still rages about the exact nature of this process and it is unlikely to be resolved soon. These 'first-order' (i.e. luminance-based) motion sensors unfortunately suffer from the aperture problem, which means that they can only detect motion perpendicular to the orientation of the contour that is moving. Further processing is required to disambiguate motion direction. Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. ...
The aperture problem
 The Aperture Problem. Each neuron in the visual system is sensitive to visual input in a small part of our visual field, as if each neuron is looking at the visual field through a small window or aperture. The motion direction of a contour is ambiguous, because the motion component parallel to the line cannot be inferred based on the visual input. This means that a variety of contours moving at different speeds will cause identical responses in a motion sensitive neuron in the visual system. Image File history File links Animated Example of the Aperture Problem. ...
Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ...
The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. ...
One way in which the aperture problem could be solved is empirically, through experience of the world.
Individual neurons early in the visual system (LGN or V1) respond to motion that occurs locally within their receptive field. Because each local motion detecting neuron will suffer from the "aperture problem" the estimates from many neurons need to be integrated into a global motion estimate. This appears to occur in Area MT/V5 in human visual cortex (Salzman et al., 1992) The lateral geniculate nucleus (LGN) of the thalamus is a part of the brain, which is the primary processor of visual information, received from the retina, in the CNS. Schematic diagram of the primate lateral geniculate nucleus. ...
Visual cortex is the term applied to both the primary visual cortex (also known as striate cortex or V1) and upstream visual cortical areas also known as extrastriate cortical areas (V2, V3, V4, V5). ...
Visual cortex is the term applied to both the primary visual cortex (also known as striate cortex or V1) and upstream visual cortical areas also known as extrastriate cortical areas (V2, V3, V4, V5). ...
Visual cortex is the term applied to both the primary visual cortex (also known as striate cortex or V1) and upstream visual cortical areas also known as extrastriate cortical areas (V2, V3, V4, V5). ...
See also the barberpole illusion. Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ...
Motion in depth As in other aspects of vision, the observer's visual input is generally insufficient to uniquely determine the 'true' nature of stimulus sources, in this case their velocity in a visual scene. In monocular vision for example, the visual input will be a 2D projection of a 3D scene. The motion cues present in the 2D projection will by default be insufficient to reconstruct the motion present in the 3D scene. Put differently, many 3D scenes will be compatible with a single 2D projection. The problem of motion estimation generalizes to binocular vision when we consider occlusion or motion perception at relatively large distances, where binocular disparity is a poor cue to depth. This fundamental difficulty is referred to as the "inverse problem." Binocular vision is vision in which both eyes are used synchronously to produce a single image. ...
Second-order motion perception Motion stimuli are classified into first-order stimuli, in which the moving contour is defined by luminance, and second-order stimuli in which the moving contour is defined by contrast, texture, flicker or some other quality that does not result in an increase in motion energy in the Fourier spectrum of the stimulus (Chubb & Sperling, 1988; Cavanagh & Mather, 1989). There is much evidence to suggest that early processing of first- and second-order motion is carried out by separate pathways (Nishida, et al, 1997). Second-order mechanisms have poorer temporal resolution and are low-pass in terms of the range of spatial frequencies that they respond to. Second-order motion produces a weaker motion aftereffect unless tested with dynamically flickering stimuli (Ledgeway & Smith, 1994). Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. ...
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In mathematics, the Fourier transform is a certain linear operator that maps functions to other functions. ...
A low-pass filter is a filter that passes low frequencies well, but attenuates (or reduces) frequencies higher than the cutoff frequency. ...
In mathematics, physics, and engineering, spatial frequency is a characteristic of any structure that is periodic across position in space. ...
The motion aftereffect (MAE) -is a visual illusion perceived after watching a moving visual stimulus for about a minute and then looking at stationary stimulus. ...
References - Adelson, E.H., & Bergen, J.R. (1985). Spatiotemporal energy models for the perception of motion. J Opt Soc Am A, 2 (2), 284-299.
- Cavanagh, P & Mather, G (1989) Motion: the long and short of it. Spatial vision, 4, 103-129
- Chubb, C & Sperling, G (1988) Drift-balanced random stimuli: A general basis for studying non-Fourier motion perception. J Opt Soc Amer A, 5, 1986-2007.
- Ledgeway, T. & Smith, A.T. (1994). The duration of the motion aftereffect following adaptation to first- and second-order motion. Perception, 23, 1211-1219.
- Nishida, S., Ledgeway, T. & Edwards, M. (1997). Dual multiple-scale processing for motion in the human visual system. Vision Research, 37, 2685-2698.
- Reichardt, W. (1961). Autocorrelation, a principle for the evaluation of sensory information by the central nervous system. In: W.A. Rosenblith (Ed.) Sensory communication (pp. 303-317). New York: MIT Press.
- Rock, I. (1983). The logic of perception, The MIT Press, Cambridge, Massachusetts.
- van Santen, J.P., & Sperling, G. (1985). Elaborated Reichardt detectors. J Opt Soc Am A, 2 (2), 300-321.
- von Helmholtz, H. (1924). Helmholtz’s Treatise on Physiological Optics. Translated from the Third German Edition. Vol. 3. The Optical Society of America.
See also Beta movement is a perceptual illusion, described by Max Wertheimer in his 1912 Experimental Studies on the Seeing of Motion, whereby two or more still images are combined by the brain into surmised motion. ...
An eye is an organ that detects light. ...
Jerkiness: In a video display, the perception, by human vision faculties, of originally continuous motion as a sequence of distinct snapshots. ...
Lilac chaser is a visual illusion, also known as Very cool illusion. ...
Max Wertheimer (Prague, April 15, 1880 - New York, October 12, 1943) was one of the founders of Gestalt psychology. ...
The motion aftereffect (MAE) -is a visual illusion perceived after watching a moving visual stimulus for about a minute and then looking at stationary stimulus. ...
Optic flow is the perceived visual motion of objects as the observer moves relative to them. ...
According to the theory of persistence of vision, the perceptual processes of the brain or the retina of the human eye retains an image for a brief moment. ...
The phi phenomenon is a perceptual illusion described by Max Wertheimer in his 1912 Experimental Studies on the Seeing of Motion, in which a disembodied perception of motion is produced by a succession of still images. ...
The Pulfrich effect is a consequence of the fact that at low light levels the eye-brain visual response is slower. ...
Rudolf Arnheim (born July 15, 1904) is a German-born author, art and film theorist, and perceptual psychologist. ...
An animation illustrating the effect of strobe light A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. ...
Temporal aliasing is the technical term for a phenomenon also known as the stroboscopic effect or the wagon-wheel effect. ...
Visual cortex is the term applied to both the primary visual cortex (also known as striate cortex or V1) and upstream visual cortical areas also known as extrastriate cortical areas (V2, V3, V4, V5). ...
This article or section does not cite its references or sources. ...
The wagon-wheel effect, sometimes called the waggon-wheel effect, or the stagecoach-wheel effect, is an optical illusion in which a spoked wheel appears to rotate differently from its true rotation. ...
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