How Do 3D Glasses Work?

Posted on 2014/05/29 at 1:11 pm by LASIK MD

How do 3D glasses work? This is a question that you’ve likely been asking yourself since you were just a kid and you had those fun 3D comic books that came with the cheap cardboard glasses with the blue and red lens. A simple understanding of how the process of seeing through 3D glasses works requires a brief discussion of three things: projection, coloured glasses, and the brain.

Movie Projection: There’s Something Tricky Going on Here…

For a 3D film to work, there must be a projection of two separate images onscreen simultaneously. These images are generally filmed at slightly different angles and then superimposed so they appear to be one big image, whether you’re viewing it with glasses or not. However, when the superimposed image is seen without the glasses, it will appear somewhat fuzzy or unfocused. This is because one of the images will be projected on the red end of the colour spectrum while the other will be projected on the blue end of the colour spectrum.

Coloured 3D Glasses: One Lens Red, One Lens Blue

The standard 3D glasses with which many of us became familiar in childhood come with one red lens and one blue lens. These different hues actually act as filters, as the red lens filters out the colour red from one eye and the blue lens filters out the colour blue from the other eye. The method behind this is so that each eye views the images in a slightly different manner. It matters not which lens is covering which eyeball, as the effect is the same regardless.

The Brain

How do 3D glasses work? This is a question that is (quite naturally) posed by the brain, but also caused and solved by the brain. The purpose behind the coloured lens filters and the superimposed image being shot from two different angles is to make the 3D glasses work like our eyes do. Ultimately, the point of using 3D glasses is to trick our binocular eyes into seeing the 2D image on the screen in three dimensions. This occurs as the tricked — and perhaps ticked off — brain creates a composite of the two images being viewed by each eye into a three-dimensional objectivity. By processing images that are just slightly different from one another due to the coloured glasses, the brain is actually hoaxed into putting them together with an illusion of depth that does not actually exist and cannot be accomplished without the effect of filtering colour from the image being transmitted to each eye.

Of course, for those of us who only desire to see in two dimensions, but still feel like they are watching “fuzzy” 3D movies without the glasses, it is probably time to see the vision experts at LASIK MD for a consultation.

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