(Newswire.net — September 11, 2021) –3D movies had a surge in popularity several years ago with the prevalence of IMAX theaters and a shift toward digital projectors. It might surprise you to learn that the science behind how 3D glasses work is not very complicated. Here are six things that can help explain the way they work.
1. The Stereoscope
3D movies might seem like a marvelous recent invention that is made possible by cutting-edge technology, but, the fact is that there have been 3D imaging devices for almost 200 years. In 1838, a man named Charles Wheatstone created a device called the stereoscope. It displayed a separate image of the same picture to each eye in a way that mimics human depth perception.
2. Anaglyphic Glasses
The first 3D movie was shown in theaters in 1922, and it used a different approach. Audience members would wear a pair of glasses that had a red lens on one side and either a green or blue lens on the other. This would filter out overlaid images of different colors on the screen, and it would cause either eye to see the same image in slightly different positions, enabling the brain to experience a sense of depth. These types of glasses are called “anaglyphic” glasses.
3. Polarization Glasses
Today, most of the 3D glasses that you get at the theater are polarization glasses. Like the green and red glasses, they use the same principle of displaying only one image on the screen to each eye. However, it accomplishes this in a different way. This method utilizes two cameras that project the same image on the screen with different polarization. The advantage of this type of technology is that the movies are viewed in full color.
4. Alternating Images
Another type of 3D technology that is not as popular but is more complex is to alternate the images on the screen. In this case, there is only one image on the screen at a time, but there are two frames shown in the succession of the same image in slightly different positions. The viewer is required to wear a special type of glasses that has shudders that rapidly shut out the view of each eye in an alternating pattern. This happens rapidly enough so that it seems like you are constantly looking at a 3D image. This technology seemed promising decades ago for 3D video games, but it never took hold in the market.
5. The brain on 3D
The human eye experiences the world as having depth because of our ability to interpret the same image from each eye from a different perspective. Since our eyes are about two inches apart, each eye sees the same thing from a slightly different angle. You will notice this when you hold up your fingers and stare at an object beyond your hand. In this case, it looks like you have eight fingers instead of four.
6. Creating Depth on the Cinema Screen
Technicians who develop 3D movies can vary the sense of the depth of certain objects on the screen by offsetting the positions of the images. In this way, the audience can “see” an object right in front of their face while another may appear to be far off into the horizon. When the dual images are farther apart, the 3D image actually appears closer to the viewer’s face.