eyeglob

I went with to see a movie in 3D.  As with any profession or hobby, people often ask about what you do for a living. So, I often get asked questions about eyes and such, and this night there was nothing different, the popular question was, “so how do they do the 3D effect?”

Ok, so we can judge depth because our eyes are apart, this allows each eye to have a slightly different image and view of an object (angle). The brain then interprets these differing views, processing and allowing us to note that the objects are at varying distances and interprets depth. This is what gives us what we call “stereoscopic vision” or binocularity.

Now, movie theaters project the image in a flat screen, so the trick here is to show each eye a slightly different image so that the brain can “fuse the image” to “see 3 D”. This is done by using polarized lenses (the best method) or red and green lenses (one eye red, one eye green). Polarized lenses are the better method, but in both cases, the idea is to filter the light so that each eye sees only one image and then the brain puts it together (fusion). An example would be the eye with the red lens would see the red image and the one with the green lens would see the green image.

Now, to the way its done, two movie projectors are then used (say one red and one green) to show the movie. Each projector’s image is seen by each eye and then they lightly offset both projections on the the screen, this is  to simulate the distance between our eyes.  Your brain will unite or we say “fuse” these two screens giving you depth to the image, or a sensation of 3D.

This is if you have two eyes that work together, people with lazy eye or say cataracts in one eye have a difficult time in the “fusion” process.

If you take your glasses off, you will notice the two projected images and the movie looks blurry!