brainwagon

I imagine that millions of Americans were watching the Superbowl this weekend, and saw the trailer for Dreamworks Monsters vs. Aliens that was broadcast in 3D. Hopefully some small subset of you actually had the glasses that you needed to view the 3D images. I was a bit curious about the technology involved, so I did a bit of digging to find the patents (yes, the 3D method is patented), and thought I’d share what I discovered.

Here’s the patent:

Method for recording and viewing stereoscopic images in color using multichrome filters

And here is the most interesting figure from the patent, showing the transparency at each wavelength for the filters which cover both eyes.

Method for recording and viewing stereoscopic images in color using multichrome filters Svend Erik Borre Sorensen et al

You’ll notice that the right eye only passes light centered around 450 nm or so, which is essentially a very deep blue. By 500nm, the filter is passing very little light, and only begins to peak back up above 700nm (which is in the invisible part of the infrared). The other eye passes virtually none of this deep blue, but actually passes relatively little of any color: it’s maximum transparency is only about 20% or so in the visible spectrum. A moment’s thought on my part tells me that this is probably by necessity: if one eye perceived a much higher luminance than the other, then all sorts of ghosting and the like occur, and it’s very unpleasant to watch. Since your eye is relatively insensitive to blue light, you need to knock down all the rest of the colors pretty sharply to keep this kind of luminance clash from happening.

So here’s the thing: the net result is that the image that you view through these glasses is dim. Really dim. Which is at least part of why I found it so hard to watch. While this method does give a surprisingly good impression of color, it’s like watching your television through a pair of sunglasses. If you are like most people, you probably have the brightness of your television set really high, because you actually like that look. Trading a nice looking 2D image for a dimmer 3D one that is hard to watch doesn’t seem like a good tradeoff to me.

But here is the real thing: none of this has anything to do with the movies that you see in stereo theaters! The 3D they use is an entirely different system which uses polarized glasses. These allow both eyes to receive full color images. Because they both receive the same color spectrum, there is virtually no luminance mismatch. The net result: your eyes feel much more comfortable. The experience is a lot better. The image (while dimmer than regular projection) is much brighter than the ColorCode 3D system.

And, so finally, we get to the real real thing: if you hated the 3D you saw in the Superbowl, don’t give up on 3D movies! What you see in the theater will be a totally different and much more pleasing experience than you likely saw on TV.

Addendum:: Talk of the Nation had an interesting podcast where they interviewed Jay Ankeney about 3D and the Superbowl. He asks an interesting question: how does showing 3D which is actually pretty bad (ColorCode) actually promote 3D which actually works pretty well (ReelD in digital theaters)?