Keywords: 3D, Red-Blue 3D Glasses, polarised 3D Glasses, How 3D effect works in Movies and 3D enabled TVs
The answer resides in our mind itself, wondering.. 😉 Well let me explain.
Human’s binocular vision system:
Our brain and eyes make an amazing binocular vision system. Our binocular system lets us easily tell with good accuracy how far an object is, for the objects up to about 6-7 meters (20 feet). For example when we see multiple objects, we can automatically tell which ones are farther and which are nearer, and how far they are.
With one eye, we can still see the objects but not with accuracy.
To see how much of a difference the binocular vision system makes, have a friend throw you a ball and try to catch it while keeping one eye closed. It is much harder to catch a ball with only one eye open than with two eyes open.
Our binocular vision system relies on the fact that our two eyes are spaced about 2 inches (5 centimeters apart. Therefore, our each eye sees the world from a slightly different perspective, and the binocular vision system of our brain uses the difference to calculate distance. Our brain has the ability to correlate the images it sees in its two eyes even though they are slightly different.
Based on this phenomenon, 3D effects can be generated by creating an illusion of depth/distance to the viewer. You can experience this experience yourself. Repeat this 2/3 times- Close one of your eye and see one object see some lamp, fan etc. Then open that eye and close another one and see the same object, after repeating this 2/3 times, you’ll feel as that object moving, coming near or going far. This is due to depth created in visualizing the same object with different eyes and our binocular system tells us the difference.
3D Glasses: 3D glasses are indispensable to enjoying 3D effect. In a movie theater or in front of a 3D-enable TV set, the reason why we wear 3D glasses is to “feed different images into your eyes “. The screen actually displays two images, and the glasses cause one of the images to enter one eye and the other to enter the other eye. Our brain then receives these two images and correlates them to one and this led to 3D effect in our brain.
Feeding separate image in each eye can be achieved by two approaches:
1. Red-Blue/Red-Green technique: In this system, two images are displayed on the screen, one in red and the other in blue (or green). The filters on the glasses allow only one image to enter each eye, and your brain does the rest. As this technique restricts use of more colours due to use of filters, we cannot get good image quality as compare to polarisation technique.
2. Polarisation Technique: In this system, two synchronized projectors project two respective views onto the screen, each with a different polarization. The glasses allow only one of the images into each eye because they contain lenses with different polarization as they have differently polarised filters at 90 degrees to each other. This makes a hi-quality 3D effect. Also it does not restrict colour-viewing so this technique is far better than Red-Blue/Red-Green technique. Hence most of the 3D systems use this technique.
Now when you’ll see a movie in 3D, you’ll know how this magic is happening, simple but amazing…. 🙂
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