Movie projector
Overview
A movie projector is an opto
-mechanical
device for displaying moving pictures
by projecting them on a projection screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie camera
s.
According to the theory of persistence of vision
, the perceptual processes of the brain
and the retina
of the human eye
retain an image for a brief moment of time. This theory is said to account for the illusion of motion which results when a series of film
images is displayed in quick succession, rather than the perception of the individual frames in the series.
Persistence of vision should be compared with the related phenomena of beta movement
and phi movement
.
Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
-mechanical
Mechanics
Mechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....
device for displaying moving pictures
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
by projecting them on a projection screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie camera
Movie camera
The movie camera is a type of photographic camera which takes a rapid sequence of photographs on strips of film which was very popular for private use in the last century until its successor, the video camera, replaced it...
s.
According to the theory of persistence of vision
Persistence of vision
Persistence of vision is the phenomenon of the eye by which an afterimage is thought to persist for approximately one twenty-fifth of a second on the retina....
, the perceptual processes of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
and the retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
of the human eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
retain an image for a brief moment of time. This theory is said to account for the illusion of motion which results when a series of film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
images is displayed in quick succession, rather than the perception of the individual frames in the series.
Persistence of vision should be compared with the related phenomena of beta movement
Beta movement
The Beta movement is an optical illusion, first described by Max Wertheimer in 1912. Its illusion is that fixed images seem to move, even though of course the image does not change. It might be considered similar to the effects of animation...
and phi movement
Phi phenomenon
The phi phenomenon is an optical illusion defined by Max Wertheimer in the Gestalt psychology in 1912, in which the persistence of vision formed a part of the base of the theory of the cinema, applied by Hugo Münsterberg in 1916....
.
