Pulfrich effect

The Pulfrich effect is an optical illusion, which was discovered in 1922 by the German physicist Carl Pulfrich.

The effect is based on the fact that bright optical stimuli are perceived by the eye faster than dark stimuli, ie darker objects in the visual field. If a sideways moving object is viewed with both eyes, one eye (such wise with a pair of sunglasses ) is darkened, the image of the object of the darkened eye a little later to perception. With this small time difference in the perception arises when a moving object that there seems to be something at two spatially dispersed locations. Of this apparent disparity, the brain determines the spatial depth information, which is not the objective.

In the example, this effect can be experienced eye well with a side to side swinging pendulum and a " darkened ". That in its plane (ie two-dimensional) swinging pendulum appears to rotate in a circular path ( three-dimensional). The apparent direction of rotation changes with the change in the darkening of the left or right eye.

Terms of effect

A better effect is obtained with the use of a laterally moving motion picture camera, generally from left to right. The recorded movie can be considered as pseudo- stereoscopic. For real stereoscopic shots a separate image is required for each eye. So there must be two aufgenommenene in eye relief images that are viewed with a real 3D glasses.

Commercial application was the Pulfrich effect in the so-called Nuoptix process, which became known with the RTL TV show Tutti Frutti. Here, however, a pair of glasses with yellow and violet color filter is used, the violet color filter strongly abdunkelte the image. In addition, various consignments at ProSieben and kabel eins were presented, which applied the method. An indirect use of the effect is used in the development of 3D television.