Moving images

To human perception enough already about 16 to 18 frames per seconds to give the illusion of fluid motion, continuity, create, unless the individual images differ only slightly from each other.

The invention of moving pictures (motion pictures) is based on series of pictures or photographs moment in the natural sequence (1, 2, 3, 4, 5, etc.), providing. The first "moving pictures" were technical advancements of the flip , as the phenacistiscope , the zoetrope or praxinoscope. With the Elektrotachyscop , the possibility of increased wall projection , it eventually led to the film .

The photographs themselves or an image carrier to be seen standing still. One speaks of interrupted or intermittent transport in conjunction with a lock on the record or a screen during playback. Between the moment or phase images , there is a dark pause. In the usual film camera a so-called breaks cycle into two parts by the complementary angle of the circular current closure are expressed, for example, 190 degrees transport dark phase and 170 degrees exposure or light phase.

The "inertia of the eye , "the so-called after-or Phi-effect has however nothing to do with the actual perception of motion in the film, which is widely believed, however erroneously. This Zglinicki "phenomena on the image persistence are based have to do with the cinematography basically nothing. Only stroboscopic phenomena - but in conjunction with the image persistence - may be addressed as an immediate precursor of the film " 

The afterimage merely provides that the individual actually different images are seen as interrelated, and the dark phases are perceived as flickering. The actual motion perception is caused by the differences in the contents of successive frames, which are interpreted by the brain as changes in position and derived velocity. This is stroboscopic called.

Flicker-free display is possible from about 45 light-dark changes per second, perceive where most people only subconsciously fibrillation.However, very bright and crisp images, even here yet lead to fibrillation. This can make for an extended period of observation of moving images noticeable by eye fatigue or headaches. From about 60 light-dark changes per second, the risk of such effects is largely eliminated.A method with 60 frames per second is Showscan .

To actually do not take 50 or 100 frames per second have been used in the film early on the trick play any of the images several times. 16 (phases -) images per second are using a three-blade aperture or a translated triple rotating bezel with 48 light-dark changes to the presentation. Recorded from 24 film frames per second, the frame rate of sound films, with the help of a two-blade aperture 48 projected images, which is a compromise between stutter-representation, minimal material consumption and perceived as a flicker-free performance.

In video and television in the European process PAL and SECAM 25 frames or 50 fields per second shown, as this is customary in European electricity networks ac frequency of 50 hertz corresponds.

In addition to the simplex method described up to now there is the duplex method .
For playback of moving images, there are various techniques. The most important are:
? Film projectors ,
? Film viewer ,
? Cathode ray tube screens ,
? Plasma screens ,
? Liquid crystal displays ,
? OLEDs ,
? Beamer .
Plasma, liquid crystal displays and OLEDs due to their not functioning affected by the flicker.
If simultaneously with the moving images and sounds are still playing, then it is an audiovisual sequence .




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