How Do 3-D Movies Work?
As an experienced ophthalmologist and expert on the human eye, I get questions about how the eyes work in all sorts of different contexts. Our eyes can help us enjoy life, and 3-D glasses represent one of the many clever ways we’ve been able to take advantage of the eyes’ natural evolution for leisure and entertainment purposes. The designers of 3-D glasses have done this by showcasing one of the most important aspects of our vision: depth perception.
Have you ever taken off your 3-D glasses while watching a 3-D movie? Chances are, the image on the screen was blurry and perhaps a little disorienting. This is because a 3-D images project two slightly different levels of depth to your eyes to create the illusion of three dimensions leaping from a two-dimensional surface. This means that there are two images projected on the screen, a bit like having two barely misaligned transparencies on top of one another.
Try closing one eye, then switching quickly to another, then between closing your right and left eye. You’ll notice that everything in your field of vision appears to move slightly each time you switch eyes. Your eyes are a couple of inches apart, which means that each eye sends a different perspective to your brain. Your brain then “computes” these two images to render a three-dimensional, and therefore more accurate, picture of the world around you. 3-D glasses, movies, and television sets take advantage of this characteristic of your vision to create the same illusion.
Simpler 3-D viewing technology uses color to separate the two images entering your eyes. These are the red-and-blue (or red-and-green) glasses that might be more likely to come bundled with an inexpensive magazine, book, or toy than a 3-D television or live viewing experience. Because they use two colors to separate the images, the color palette is limited with this technology. Thus, the picture quality tends to be low, and 3-D images that work with color-filter glasses can be projected from an ordinary television. You’re far more likely to use polarized 3-D glasses during a 3-D blockbuster movie or ride at Universal Studios.
Polarized 3-D glasses work by delivering two images to your eyes, and this more sophisticated technology allows for far superior image quality. During a 3-D film or ride, two projectors are synchronized to render two slightly different perspectives of depth onto a surface. Each lens of the 3-D glasses is polarized differently, as is each image being projected from the screen, so each eye only allows one of the images in. Polarized sunglasses use the same technology to filter out harmful radiation that polarized 3-D glasses use to filter out half of a 3-D projection. The fact that this method uses two images from two different perspectives makes it very similar to how your eyes work when viewing actual three-dimensional objects. There are other, more complex methods of creating 3-D images, but that complexity makes them cost prohibitive and therefore relatively uncommon.
At Georgia Eye Physicians & Surgeons, we aim to satisfy people’s curiosity about everything we can, from fascinating factoids to eye-health concerns. If you’re interested in any of the many services we offer, please contact Georgia Eye Physicians & Surgeons to schedule an appointment today. Be sure to follow Dr. Segal and Dr. Lay on Facebook and Twitter for more interesting information, tips on eyecare, and the latest news and updates about eye health.