How Do 3D Movies Work? 

Source of pictures: pixabay.com

"Mackle, are you free this weekend? Let's go to the cinema. I just heard of a new movie. Its 3D effect is fantastic!" It was a message from his good friend Linda. He likes watching movies very much for movies are always full of imagination and always brought him novelty and happiness. He particularlyprefers blockbusters with 3D effects, so he accepted the invitation without hesitation.

At the weekend, Mackle and Linda went to a movie theater and bought tickets for the hottest 3D blockbuster of the winter. Mackle put on the 3D glassesprovided by the service personnel. He sat down and waited for the movie to start.

The movie was extremely amazing. When he was going to the bathroom halfway, he took off the glasses and walked out of the projection hall.However, he was unwilling to miss even one plot, so he looked at the screen before going out. "Oh, I can see nothing," He said to himself, "I could just see the image. Why can't I see anything without 3D glasses now?" He was thinking about this question on the way to the bathroom. Why can he see3D movies with the help of 3D glasses? How is the 3D movie filmed?

3D movies are not filmed with complex methods. They come into play by applying principles of optics and how we look at things with our eyes. Due to the different positions of our two eyes, the sights seen by left and right eye are actually not the same. The subtle difference of two sights enable people to perceive the sense of three dimensions and distance. We can feel the three dimensions of objects when different images are respectively sent into two eyes through a certain method.

What on earth is going on? In fact, the 3D movie is shot by two cameras at the same time, just like the two eyes of people. The pictures filmed by disparate camera have nuances. When the film is showed, two different videos are screened by two projectors. Therefore, two images are simultaneously displayed on the screen. If you don't wear 3D glasses, you will see the overlapped pictures, which are extremely blurred. So how to show different pictures for two eyes respectively?

We need to put a polarizer in front of the two projector lenses when the film is screened. What is a polarizer? The natural light is made up of light rays fromall directions. The polarizer is the lens composed of tiny gaps with only one direction. When light rays pass through the polarizer, other light rays thatcome from different directions cannot pass. Only those light rays having the same direction as the gap can pass through the polarizer.

Two projectors are installed with polarizers with gaps of different directions. For example, if we put a polarizer with gaps of the vertical direction in front of the first projector, only the vertical light can pass through it. We placed another one with gaps of horizontal direction in front of the second projector, andonly the horizontal light can pass through. In this way, images projected onto the screen are composed of two sets of light rays of different directions.

The next problem can be solved by "3D glasses". You may have known that the 3D glasses are also polarizers. Its two lenses are two polarizers of different directions, corresponding to the direction of the light rays reflecting from the screen. Two sets of light rays in different directions will enter into your two eyes respectively, instead of into both eyes simultaneously, and the brain will inform you that these images are three-dimensional.

This is why you can see the 3D movie. What do you think? Is it amazing?

Author: Ya Wen