Persistence of Vision

Introduction to persistence of vision:

Persistence of vision is the theory or phenomenon which explains that our retains the image of whatever we see for almost 1/25 second or twenty-fifth of a second or 0.04 seconds. This retained image is called the after image.

So according to this theory of Persistence of vision whatever we see or observe is actually a subtle blend or mix of images at the intervals 0.04 seconds, (that is a blend of images of what is happening now and what had happened a fraction of second back.

The theory of persistence of vision is believed to have been discovered by Lucretius,a Roman poet, although he had mentioned about persistence of vision only in connection with images seen in dreams.

Now a days it has become a common belief of thinkers and scientists that this theory is just a myth.


Persistence of vision examples:


FILM SYSTEMS
A film or a video is made of of number of still images known as frames. This frames are played one after the other with an time interval of less than 0.04 seconds.
This is accounted on the basis of persistence of vision in human, because of which we retain the first frame seen till 0.04, and after 0.04 seconds our eye looks out for another frame of the video. So a frame is changed just in an interval of 0.04 seconds, and our eye observes this to be a continuous video or film.
Thus the minimum frame rate for a video to appear continuous is 25fps( frame per second)

Cartoon Animation
Cartoon animations are also made up of  still images. In cartoons lesser number of frames are used each second.
Mostly they show the same drawing in two frames.That means for a cartoon animation having frame rate of 26fps, only 13 different drawings are shown.

Is Persistence of vision a myth:


In the year 1912 Theory of Persistence of vision was debunked, as their was no scientific proof to prove how this theory works.

Two modern theories that replaced this and have more scientifically  strong base are Phi phenomenon and Beta movement.