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Apparent Motion (other)
Apparent motion may refer to: Astronomy *Aberration of light, an apparent shift in position of celestial objects due to the finite speed of light and the motion of Earth in its orbit around the Sun * Diurnal motion, the apparent motion of objects in the sky due to the Earth's rotation on its axis *Parallax, the apparent motion of objects due to the changing angle of observation of an observer on Earth revolving around the Sun Perceptual illusions *Beta movement, an illusion of movement where two or more still images are combined by the brain into surmised motion *Illusory motion, the appearance of movement in a static image *Phi phenomenon, an illusion of movement created when two or more adjacent lights blink on and off in succession *Stroboscopic effect, a phenomenon that occurs when continuous motion is represented by a series of short or instantaneous samples **Wagon-wheel effect, temporal aliasing effect in which a spoked wheel appears to rotate differently from its true rotati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aberration Of Light
In astronomy, aberration (also referred to as astronomical aberration, stellar aberration, or velocity aberration) is a phenomenon where celestial objects exhibit an apparent motion about their true positions based on the velocity of the observer: It causes objects to appear to be displaced towards the observer's direction of motion. The change in angle is of the order of where is the speed of light and the velocity of the observer. In the case of "stellar" or "annual" aberration, the apparent position of a star to an observer on Earth varies periodically over the course of a year as the Earth's velocity changes as it revolves around the Sun, by a maximum angle of approximately 20 arcseconds in right ascension or declination. The term ''aberration'' has historically been used to refer to a number of related phenomena concerning the propagation of light in moving bodies. Aberration is distinct from parallax, which is a change in the apparent position of a relatively ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphical), foreshortening, nearby objects show a larger parallax than farther objects, so parallax can be used to determine distances. To measure large distances, such as the distance of a planet or a star from Earth, astronomers use the principle of parallax. Here, the term ''Stellar parallax, parallax'' is the semi-angle of inclination between two sight-lines to the star, as observed when Earth is on opposite sides of the Sun in its orbit. These distances form the lowest rung of what is called "the cosmic distance ladder", the first in a succession of methods by which astronomers determine the distances to celestial objects, serving as a basis for other distance measurements in astronomy forming the higher rungs of the ladder. Because parallax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Movement
The term beta movement is used for the optical illusion of illusory motion, apparent motion in which the very short projection of one figure and a subsequent very short projection of a more or less similar figure in a different location are experienced as one figure moving. The illusion of motion caused by animation and film is sometimes believed to rely on beta movement, as an alternative to the older explanation known as persistence of vision. However, the human visual system can't distinguish between the short-range apparent motion of film and real motion, while the long-range apparent motion of beta movement is recognised as different and processed in a different way. History Observations of apparent motion through quick succession of images go back to the 19th century. In 1833, Joseph Plateau introduced what became known as the phenakistiscope, an early animation device based on a stroboscopic effect. The principle of this "philosophical toy" would inspire the development ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illusory Motion
The term illusory motion, or motion illusion or apparent motion, refers to any optical illusion in which a static image appears to be moving due to the cognition, cognitive effects of interacting color contrasts, object shapes, and position. The Stroboscopic effect, stroboscopic animation effect is the most common type of illusory motion and is perceived when images are displayed in fast succession, as occurs in movies. The concept of illusory motion was allegedly first described by Aristotle. Types of illusory motion Induced movement works by moving the background around a fixed object. Films such as ''Airplane!'' and ''Top Secret!'' use a fixed prop and move the background props to give the effect of induced motion. Motion aftereffect occurs when one views moving stimuli for an extended period of time and then focus on a stationary object. The object will appear to move in the opposite direction of the moving stimuli. Mechanics of illusory motion perception Illusory motion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phi Phenomenon
The term phi phenomenon is used in a narrow sense for an Illusory motion, apparent motion that is observed if two nearby optical Stimulus (psychology), stimuli are presented in alternation with a relatively high frequency. In contrast to beta movement, seen at lower frequencies, the stimuli themselves do not appear to move. Instead, a diffuse, amorphous shadowlike something seems to jump in front of the stimuli and occlude them temporarily. This shadow seems to have nearly the color of the background. Max Wertheimer first described this form of apparent movement in his habilitation thesis, published 1912, marking the birth of Gestalt psychology. In a broader sense, particularly if the plural form ''phi phenomena'' is used, it applies also to all apparent movements that can be seen if two nearby optical stimuli are presented in alternation. This includes especially beta movement, which has been regarded as the illusion of motion in film, cinema and animation, although it can be argu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroboscopic Effect
The stroboscopic effect is a visual optical phenomenon, phenomenon caused by aliasing that occurs when continuous rotational or other cyclic motion is represented by a series of short or instantaneous samples (as opposed to a continuous view) at a sampling rate close to the period of the motion. It accounts for the "wagon-wheel effect", so-called because in video, spoked wheels (such as on horse-drawn wagons) sometimes appear to be turning backwards. A strobe fountain, a stream of water droplets falling at regular intervals lit with a strobe light, is an example of the stroboscopic effect being applied to a cyclic motion that is not rotational. When viewed under normal light, this is a normal water fountain. When viewed under a strobe light with its frequency tuned to the rate at which the droplets fall, the droplets appear to be suspended in mid-air. Adjusting the strobe frequency can make the droplets seemingly move slowly up or down. Depending upon the frequency of illuminatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wagon-wheel Effect
The wagon-wheel effect (alternatively called stagecoach-wheel effect) is an optical illusion in which a spoked wheel appears to rotate differently from its true rotation. The wheel can appear to rotate more slowly than the true rotation, it can appear stationary, or it can appear to rotate in the opposite direction from the true rotation (reverse rotation effect). The wagon-wheel effect is most often seen in film or television depictions of stagecoaches or wagons in Western movies, although recordings of any regularly spoked rotating object will show it, such as helicopter rotors, aircraft propellers and car rims. In these recorded media, the effect is a result of temporal aliasing. It can also commonly be seen when a rotating wheel is illuminated by flickering light. These forms of the effect are known as ''stroboscopic effects'': the original smooth rotation of the wheel is visible only intermittently. A version of the wagon-wheel effect can also be seen under continuous i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Flow
Optical flow or optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and a scene. Optical flow can also be defined as the distribution of apparent velocities of movement of brightness pattern in an image. The concept of optical flow was introduced by the American psychologist James J. Gibson in the 1940s to describe the visual stimulus provided to animals moving through the world. Gibson stressed the importance of optic flow for affordance perception, the ability to discern possibilities for action within the environment. Followers of Gibson and his ecological approach to psychology have further demonstrated the role of the optical flow stimulus for the perception of movement by the observer in the world; perception of the shape, distance and movement of objects in the world; and the control of locomotion. The term optical flow is also used by roboticists, encompassing related techniqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
