Autostereoscopy: 3D Without Glasses

by Johnny Knoxville II

By now, most all of us have been introduced to 3D (stereoscopic) films, if not having tried our hands at 3D filmmaking using the various consumer 3D camcorders that have come onto the market. Exciting times we live in!

We've become familiar with our wearing 3D glasses or headgear of some kind that have a lens before each of our eyes, in order to enjoy the stereoscopic effect.  In fact, we may even associate this setup with stereoscopy. 

However, though most popular at this time, these are not the only technologies out there for creating three dimensional illusions in imagery.  Let's have a look at some other techniques, which many organizations are also developing (but we'll have to see when and if they make it into the mainstream TV market):

Firstly, the official term for referring to stereoscopy that does not need the viewer to wear any special glasses or headgear, is referred to as "Autostereoscopy".  The very basics of creating a stereoscopic image of course is to create a slightly different picture seen from the two slightly different angles the two eyeballs of the viewer are based.

One way this is accomplished is through what is called "lenticular lenses".  You may have seen them as a child when you had those little rulers with the pictures on them, that would seem to move as you move the ruler and look at it from different angles.  Some fancy "tazzos" or tokens you could collect as part of the Pokemon, Digimon and other marketing ploys also made use of this technology.  In this case it was basically used to simulate an animation or simple movement of the image. 

The same way these lenticular lenses can be used to seem to create a different image from a different angle, so they can be used to show two different images to the two eyes.  The lenticular lens is an array of magnifying lenses, designed so that different images are magnified when viewed from slightly different angles. 

Another way to create 3D illusions is to use what is called a parallax barrier.  A parallax barrier is a device placed in front of an image source, such as a liquid crystal display, to allow it to show a stereoscopic image without the need for the viewer to wear 3D glasses. Placed in front of the normal LCD, it consists of a layer of material with a series of precision slits, allowing each eye to see a different set of pixels, so creating a sense of depth through parallax.  One disadvantage though is that the viewer will have to be in just the right spot for the effect to work.

An interesting application of this technology (though not for 3D) is its use in the navigation system in the 2010-model Range Rover, allowing the driver to view GPS directions, while a passenger watches a movie, both seeing a different image from where they sit.

Another fun 3D creation is what is called an "Autostereogram".  These are what we see published many times in magazines, where a picture may seem like many messy pixels, or a lot of repeating patterns, but if you can train your eyes to look "inside" the picture, you can clearly make out a 3D shape, usually against a background further "in".  Or many repeating objects, usually in horizontal rows, may seem to be at different depths.  Autostereograms are popular as still pictures, but they can of course also be animated. 

These are just some other ways (though not the only other ways) of creating a stereoscopic illusion.  Let's see what the future brings :)