Effectively, even if it is incredible, our brain creates an optical illusion when we visualize our environment, this is based in two images that, separately, are captured through each eye. In other words, our brain would not be able to communicate the volume effect without all the information captured thanks to the eyes, perspective, size, plans, etc, that surrounding objects include .
So, if we cover an eye could we see the world in 3D? Yes exactly, with the caveat that if what we are watching, we have already seen it before, our brain will remind everything and it will be able to deceive us, once again, thus giving us a 3D effect.
If you want to prove this effect, you can go to an unknown place and there, you should cover just one eye: could we be able to detect the different distance between objects? The answer is no, let’s see why.
The 3D perception is based in philosophy and psychology processes related to monocular and binocular vision that creates volume sensation and gives the objects a solid aspect. Moreover, they are situated in a specific place in the space.
Monocular vision is related to one eye; it means that plane images are processed by our brain and thanks to different factors we are able to receive 3D images. Among all factors we can find the perspective, size of an object, projected lights from different angles and its shadows; or even, the superposition of the objects that indicates us what is in front or behind. In other hand, at the binocular vision, both eyes are situated in different positions; each one detects different images from reality. These small differences are processed in our brain in order to calculate the distance where objects are placed, getting a volume or profundity sensation.
This is the base of the stereotyping, in other words, all techniques are able to collect visual information and to create depth illusion. For example, in the cinema, on TV screens or even portable players, all these objects are based on this technique, in order to create a 3D effect in our brain.
Overall, if we choose two images with slightly different angle and we watch each through a different eye; then, the brain will be able to reconstruct the distance, and of course, a 3D sensation. This simple effect has been used from 1840 when Sir Charles Wheatston invented this technique.
Nowadays, there are two different ways of “emit” in 3D; by using glasses, as we have said before, 3D optical illusion in a two-dimensional surface can be created by proving different information to each eye.
The classic 3D glasses create 3D illusion while watching special images. Most know glasses are called anaglyph they include two lenses –red and blue- that transfer a different image each. Another kind of 3D glasses includes polarized filters, -one vertically and other horizontally-. Polarized 3D allows specifying 3D colors; otherwise, red-blue lenses create an image in a specific white/black color with red and blue stripes. It also exist another kind of glasses that use an electronic shutter that allows each lent to get darker and darker in quick intervals which are imperceptible for the human eye, that is why each eye receive a different image.
The second method, which is technologically more advanced, allows us to rule out glasses, thanks to screen evolution, so they will provide us different information to each eye, amazing, isn’t it? Most popular technique is called “Parallax Barrier” which end image is created by interpolating columns from two images with two separately cameras with similar distance to the eyes distance. This final image and a vertical grille are alienated, so left eye can see the image stripes, in order that both eyes could watch image stripes for right eye. Another technique, much more advanced, which will be the future 3D, is the lenticular, using a lenticular sheet, which is based on using parallax barrier; what is more, one of the advantages is that you do not need to be alienated with e screen for receive 3D sensation.
In short, our eyes are like digital cameras that receive 2D plane images. Another technique much more advanced will be the future of the 3D, called lenticular sheet, which uses a lenticular sheet –slight and long lens sheets which gets the same effect that the parallax barrier, but one of the main advantages I that it is not necessary to be alienated with the screen in order to perceive 3D sensation.
Summarizing, our eyes are like cameras that can visualize 2D images, due to existing separation between both eyes, this binocular vision can visualize two images which are slightly different, and these differences may vary due to the distance where some objects are placed in our field of vision. Our brain is the one to interpret those plane images, and creating the common known 3D effect.
Different systems of 3D vision try to visualize the way that our eyes detect all images from the real world, in order to perceive the image in a flat screen as it was in 3D; just remember that is our brain which creates the 3D effect.
Written by José Serrano Verdejo (Product Manager)