how they put the motion in motion pictures - slide projector

This summer, many of us were sitting in the dark theater, staring at the screen and displaying other world-fascinating events on the screen.
In "contact", aliens communicate with Judy Foster.
In the black man, Will Smith fights a giant alien cockroach.
In Lost World, velociraptors skip the grass, T.
Rex threatened the suburbs.
In this unusual action, it is easy to forget that, despite what their name is, the movie is actually a series of static pictures.
No movement on the screen;
All the moves are in our heads.
So why didn't we notice this when we were looking?
How do continuous static pictures create the appearance of motion?
It is worth noting that a key to achieving the effect is to dim the screen for a short but necessary time between each pair of still images or movie frames.
As it happens, over half the time we watched a movie, the screen was black and the theater was black.
This is something else we didn't notice.
Scientists don't fully understand how movies work, because our visual systems are so complex that the way we process movie images is too complicated.
But since the beginning of the 19 th century, the study of this phenomenon, we have come closer to understanding the subtle interactions between the brain, the eyes and the rapidly changing sequence of static pictures.
The study will lead to the invention and development of the film, which began almost two centuries ago.
About 1817, Sir John hershere, a British scientist, bet with a friend that he can show the head and tail of a preorder at the same time.
When Helel spun the coin on a table, his friend saw the rotating face of the coin fused into an image.
This phenomenon is called "visual persistence ".
"In 1824, Peter Mark Roger, author of the famous thesaurus, was also an early experimenter of this phenomenon, define visual persistence as "the ability of the retina to hold images from 1120 to 115 seconds after the object is removed from the field of vision.
While Roget's conclusions were too simplistic, his work encouraged the invention of several motions --
A device that simulates the motion picture.
For example, in 1825, John Elton of Paris developed the most famous Thaumatrope in the early "visual persistence" toy.
This is a disc with a picture of a parrot on one side and an empty cage on the other.
By spinning the disc like Herschel's coin, the viewer sees a picture and then another picture, two pictures merged: the parrot is in the cage.
On 1829 Joseph Plateau, a Belgian, published his investigation into the same phenomenon.
Plateau repeated a simple experiment over the years.
He would stare at the sun and then study faded optical images in the dark.
At the age of 28, his experiment blinded him.
A few months later, he partially recovered his vision, and in an extraordinary example of scientific dedication, he resumed the experiment and found that his vision was permanently damaged at the age of 40.
However, with the help of his wife, Plateau continued to carry out less harmful experiments until the death of 82.
He sold a toy in 1832, which he believed proved his theoretical research.
Around the edges on one side of the disk is a series of 16 still pictures with slightly different positions.
There is a gap between each pair of images passing through the disk.
The audience took a handle with the disk, rotated it and looked at the cracks in the mirror.
When a slit appears in front of the eye, allowing to see the mirror, the reflection image of a still image is briefly visible.
The picture seems to be moving when the disk rotates.
Plateau called his toy a "deceptive audience" from Greece. " {
You can make a phenomenon mirror.
Please see the following phenomenon. }
Plateau inadvertently used two features, which were later considered to be the basic feature of the film.
When the viewer is staring at the disk, the eye sees a brief darkness between each pair of still images.
In addition, the machine displays 16 images per second fast enough to create the illusion of continuous motion.
It was not until the analogy of the plateau slit was discovered that a successful projector was invented, and early filmmakers quickly realized the validity of 16 frames per second.
At the same time, others are also working on similar technologies.
In Vienna, Simon Ritt von staplver independently made a toy similar to the phenomenon mirror.
In 1834, William George Horner changed the disc to a round drum.
The paper tape with the image is placed inside the drum, and when the audience looks at the rotating drum through thin seams, the picture on the paper becomes animated.
Because the paper can be replaced, various moving pictures can be displayed on the same machine.
Horner first called his toy "Daedelum" and then called it "Zootrope" or "Zoetrope ".
In 1843, an Austrian artillery officer named Baron Franz von uchati began to work on a film projector.
He combined the Phantom mirror with the magic light and the candle.
Power slides.
Uchatius has installed a clear glass plate consisting of many slightly different graphics and a separate opaque plate with a slit.
The crank rotates two discs and the lamp projects the image onto the wall.
Many people the first time can at the same time watch animation.
The movie projector was born and, surprisingly, its working principle remained basically the same.
The idea of "visual persistence" is based on the belief that when a single image is formed on the retina, even if the viewer's gaze shifts to another object, it stays there briefly
Scientists speculate that when the next image arrives, it will somehow blend with the reserved image to create the illusion of continuous motion image flow.
In fact, the persistence of the vision is true.
When you close your eyes, images of shapes and colors seem to remain visible briefly, especially when the scene is illuminated brightly.
However, modern researchers do not believe that this phenomenon, called "the posterior image of the retina", can explain film vision.
Instead, they describe two other phenomena that begin to explain how continuous still frames produce the appearance of fluid motion: critical flicker fusion and apparent motion, or, as it is also known as strobography.
These phenomena--
Scientists have yet to fully understand-
Make the movie action look as smooth as real life.
Critical Flicker fusion refers to the impression that if they are close enough to the astigmatism flashing interval, they merge into continuous light.
For example, fluorescent lamps are turned on and off 60 times per second.
They will leave as long as they are still there.
But, of course, they seem to provide continuous lighting.
Since the eye is unable to handle the rapid change in brightness, we treat the off-astigmatism pulse as continuous light.
Without this fusion, Plateau's audience would notice a pause between the images in his phenomenon mirror.
In the early days, filmmakers accepted Plateau's frame rate of 16 frames per second as a magic number.
More frames per second will not make the motion look smoother. But with hand-
It is not easy to achieve a stable speed.
Normally, the camera takes pictures at 12 to 15 sheets per second.
The film is shown at a steady rate of 17 frames per second, which means silent
Movie stars like Charlie Chaplin seem to go fast.
Acceleration gets worse when old movies are projected through a late Machine of 24 frames per second.
However, even in the case of 16 fps, the flashing problem still exists, swinging between light and light.
This leads to "flashing", an early slang term that will be recalled today when we call a movie "movie.
When "talk Pictures" appeared in late 1920, the problem was partially improved.
The sound track recorded in a narrow lane is the easiest to coordinate with the picture, 24 frames per second, and this speed becomes the standard "sound speed" today ".
"But there is still an obvious flicker.
It was eliminated by a clever solution. -
Before the image changes, the shutter is turned on and off three times when a single frame is projected.
In other words, the projector places a frame in front of the bulb and continuously projects its image when the shutter is on and off, sends the image to the screen, before the projector pulls the next frame in place, block it and send it again.
This is done by an opaque disk with holes on the disk rotating in front of the film.
In the case of 24 frames per second, the image and blackness alternate 72 times in one second.
In fact, there was a little more than half of the time we watched the movie, the screen was actually blank, and we were sitting in a completely dark place.
Studies have shown that the exact frequency of flicker disappearance depends on the intensity of the light, the wavelength, duration, the relative area of the illuminated field of view, the location where the retina is stimulated and the age of the audience.
With these variables in mind, it is safe to say that in the case of typical motion image viewing, flashing fusion--
The point of flashing away--
Occurs about 50 flashes per second.
The film's 72 fps flashing rate is far beyond the ability of any viewer to notice moving frames.
While the key flicker fusion allows us to watch the movie without noticing the light from dark to dark and the shift from dark to back, to convince us that the still image is moving, the obvious movement is not from the frame to the frame.
The "apparent movement" allows the eye and mind to connect the stroboscopic succession of the still frame.
In cognitive scientists, the traditional view is that a psychological event called the "phi phenomenon" provides a psychological bridge between such frameworks.
According to this explanation, the mind somehow fills the gap between the still images.
The history of Phi can be traced back to the early 20 th century.
School of Psychology, Century gestalt
The basic idea of the Gestalt is that the whole of everything is what we perceive, not a collection of parts.
The word Gestalt is used in modern German to indicate the way something is either gestellt or combined.
In 1912, Max Wertheimer, a Gestalt psychologist, found that when two lights flashed next to each other,by-
At a certain time interval, what the audience sees is not two flashing lights, but a moving light.
Wetheimer believes that the clear jump of light from one position to another is a paradox that the brain has to solve.
The brain's conclusion that light is moving is simpler than the conclusion that two different lights are coordinated, so that when one light is turned on, the other light is turned off.
Film theorists who use the Gestalt theory believe that viewers may be using similar unconscious thought processes to create motor illusions.
This is thought to be something similar to what produces the illusion of intermediate motion.
Examples of the obvious desire of the brain to simplify ambiguity include several images that are familiar to the students of perception: inverted cubes and old/young women, etc. {
Meet the illustrations to the page. }
In these cases, the visual system presents two sets of incompatible information.
For example, in the same photo, one cannot see both the old woman and the young woman at the same time, although all the information about each of these explanations is contained in vague numbers.
The audience can only alternate between seeing an old woman and a young woman.
These numbers illustrate a "winner --takes-
The whole strategy of human perceptual system.
But, like "The Persistence of Vision"
Alzheimer's "phi phenomenon" is considered an incomplete explanation of film vision.
Recent experimental work has shown that our visual perception is only flawed but purposeful.
Research shows that the way we watch movies is not necessarily different from the way we see real movements in nature.
Cognitive researcher Joseph D in his recently published book The Reality of illusion
Anderson wrote, "the visual system simply cannot detect the real difference between the continuous change of the static frame of the Moving Image and the continuous change of the natural motion.
While the brain is sometimes compared to a computer, Anderson explains, its cells process information much slower than silicon chips.
The brain has developed strategies to make up for it.
One is the way data is compressed or compressed. -a shortcut --
This enables the brain to keep up with the incoming information of events in the world, such as the movement of objects.
It is the brain's natural use of this shortcut strategy that opens the way for filmmakers to introduce synthetic movements that the brain cannot distinguish from real movements.
The illusion of film provides a valuable perspective for the complexity of our perception system.
Although it accepts inaccuracies, the system is clearly enough to meet our needs, and in fact, the system is good enough in terms of film.
This visual quirk leads us to believe in the magical reality on the walls of the dark room.
However, when "Godzilla" comes to town next summer, you may want to calm your fears with the knowledge that monsters don't really move on the screen ---
You're just compressing data.
Mark Rambler is a freelance writer in New York.
Description: like a crank
Operate Rolodex, the 1901 devices play the movie by flipping the card, each with a still photo.
Description: At the beginning of the movie, the theme was simple.
In 1894, Thomas Edison's studio filmed a film of sneezing.
Description: In 1895, the brothers of Lumiere in France invented the film camera and projector.
Description: scientists used to think that we saw motion in movies because the brain automatically explained the blurred images.
Here is the example.
The two faces of the cube can see the projection, but the two faces cannot be seen at the same time.
Only old women or young women can be seen at certain moments.
Description: 1887 "praxinoscope" projects movie clips using lights and mirrors.