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Persistence of vision

  1. Jan 1, 2005 #1
    I know it is used to refer to the property of brain/eye that it takes them one-tenth of a second to process a new image after processing one but I just cant figure out how does a movie camera takes advantage of it and fool our brain so that it thinks that its waching a smooth motion though i know that most of them change 24 images a second. I've tried google but coundnt find anything convincing.
    Thanks in advance for any help. :smile:
    Abdullah
     
  2. jcsd
  3. Jan 1, 2005 #2

    Integral

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    A film projector flashes images at about 30 frames per sec. So each frame is on the screen for a period of time which is less then the persistence of the eye. Before 1 frame has faded a new one is present. Thus you get the feeling of smooth motion.
     
  4. Jan 1, 2005 #3

    rcgldr

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    This only works well under dark light, with your pupils dialated and your retina getting just enough over-saturation that the persistance increases.

    Under bright light, you can see 60hz flicker on a monitor, but part of this is that the persitance of the monitor is set for faster refresh rates.
     
  5. Jan 1, 2005 #4
    here is a neat page with a simple explanation and demonstrative animations:
    http://www.privatelessons.net/2d/sample/m01_03.html

    however, it seems that the persistence of vision 'theory' may not be correct at all according to research done in the 1980s and that it is really a psychological phenomenon. here is a rather interesting (and surprising - to me at any rate) article on that matter:

    it has in fact long been determined that the so-called 'persistence of vision' is also probably irrelevant to the effect of (1), a continuous, flickerless image.
    PERSISTENCE OF VISION by Stephen Herbert
    http://www.grand-illusions.com/percept.htm

    it would seem that the commonly propagated explanation of illusion, may itself be an illusion!
     
    Last edited: Jan 1, 2005
  6. Jan 2, 2005 #5
    Given that the brain takes at least 50mS to process data and somtimes never it's hardly surprising that persistence should be more complex than retina saturation , it is often the case that what you remember is totally different from reallity --- so I guess you can say that everbodies movie is probably different antway.
    Ray.
     
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