Usually, making 2D things into 3D things involves tricking the eye using special glasses, which make you perceive something has depth when it really doesn't. Surprisingly, the next advance in 3D could come by way of a gadget first invented in 1907, one that goes straight for your brain instead.
Synoptic 3D was invented a hundred years ago buy a Polish guy named Moritz von Rohr. His synoptic viewer was a device that you could hold up to your eyes and look through like binoculars, and, by bouncing light around to make sure that both of your eyes were seeing an image from the same perspective, it could cause your brain to see 2D pictures in 3D.
This is basically the exact opposite of stereoscopic 3D. A synoptic 3D system fools your brain into thinking that it's looking at a distant 3D landscape instead of a close-up 2D screen, sort of like what happens when you look through a window. So, instead of relying on fake depth information, your brain uses natural visual cues, and simply imagines a 3D scene based on what it can see.
Since your brain does all of the 3D work on its own, you could use a synoptic 3D system with anything at all; pictures, movies, whatever. Just look at something 2D through a synoptic viewer, and bam, your brain makes it 3D.
It's also a much more natural experience: if you've ever tried to look at something in the background of a 3D movie instead of whatever is currently blasting out of the screen at you, you know things can get a little wonky. Synoptic 3D isn't going to solve the problem of having to wear those horrible glasses, but at least you won't walk out of the movie theater with blurred vision and a headache.
Via New Scientist