Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur Graph Search.
Concept
Effet bêta
Résumé
The term Beta movement is used for the optical illusion of 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, there are notable differences between the short-range apparent motion that occurs in film (with little differences between successive images) and the long-range apparent motion originally described as beta movement (with bigger differences between positions of successive images).
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. It was often assumed that the animation effect was due to persistence of vision in the form of afterimages on the retina or a mental process that filled in the intervals between the images.
In 1875, Sigmund Exner showed that, under the right conditions, people will see two quick, spatially separated but stationary electrical sparks as a single light moving from place to place, while quicker flashes were interpreted as motion between two stationary lights. Exner argued that the impression of the moving light was a perception (from a mental process) and the motion between the stationary lights as pure sense.
In 1912, Max Wertheimer wrote an influential article that would lead to the foundation of Gestalt psychology. In the discussed experiments, he asked test subjects what they saw when viewing successive tachistoscope projections of two similar shapes at two alternating locations on a screen. The results differed depending on the frequency of the flashes of the tachistoscope. At low frequencies, successive appearances of similar figures at different spots were perceived.
Source officielle
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.