stereoscopic (”3D”) television
One of the projects I’m excited to be working on is stereoscopic or “3D” television. I’m going to be showing one off at Foo Camp this weekend. There’s a lot of good websites on the topic but I’m going to try to give a superfast, biased tutorial of what you need to know. As expected, a good dry tutorial can be found at Wikipedia.
1) To create a 3D effect you need to show a different view to each eye. This can be accomplished in a variety of ways, and glasses is the most common way to get the effect in movie theatres or with monitors.
2) Floating 3D where you don’t have to wear glasses is called “autostereoscopic”. Printed holograms are autostereoscopic. They’ve been around for decades and they don’t look like the princess leia hologram from episode IV, do they? Autostereoscopic monitors exist - but they don’t use laser beams to draw the image miraculously in front of your eyes. Rather, they’re similar to the amusing but bad holograms we’re used to. Try not to think about autostereoscopic technology for now so we can get back to reality.
3) You can buy one kind of 3D television today. They use what are called shutter glasses. They’re heavy, and they alternately blank each eye based on signals they get from the TV. There’s another type of 3D television coming out on the market, that uses polarized glasses, using the same tech in the theatres. You can purchase 22″ 3D monitors using this technology now. A good analysis of the different approaches can be found on the Real-D blog.
4) Movie theatres currently display a pretty good form of 3D using “passive” glasses that are lightweight and don’t have batteries or shutters. They give a different image to each eye. The glasses probably cost less than $1 since they give you one free with your ticket.
5) The easiest movies to make into stereoscopic form are computer-generated animated movies, since they are modeled in 3D on the computer to begin with. Converting existing 2D movies to a simulated 3D (sort of like colorizing a film) is a labor-intensive, manual, computer-assisted process. Shooting good 3D cinema (with stereo cameras) has a tremendous learning curve but a number of major directors are starting to do just that.
6) There’s a huge pipeline of 3D movies. Some of the stats I’ve heard point to there being a new 3D movie every month in the next couple of years. Thus, it’s natural that you’d want a 3D television if you’re the wait-for-DVD type.
7) There has been 3D television for years, in the form of shutter glasses and frame-flipping TVs. There’s a de-facto standard called “field sequential 3D” and you can buy DVDs of this type of content on Amazon.com as well as a variety of hole-in-the-wall specialty e-tailers. The quality has never been that compelling however, because the DVDs are only 720×480 pixels. New 3D televisions and LCDs run at full 1920×1080 HD resolution, so that the frame to each eye is approximately 1920×540 worth of data, because half the lines go to the left eye and half the lines go to the right eye.
The red-blue or red-cyan glasses approach is called anaglyph. It’s great for 3D comic books and short content sent over television. The color variation of broadcast however is so high that it’s hard to get a consistent effect over broadcast TV. Plus, it alters the natural color of the scene. Anaglyph techniques are good demonstration, but will never be a mass market product.
9) You can encode stereoscopic content on a Blu-ray. Candidate formats are side-by-side and over-under. Side-by-side would provide a 960×1080 pixels of image quality to each eye; over under, 1920×540. Depending on the approach used to provide the 3d, these images would be expanded to fit the screen (shutter glasses alternate eyes in time; polarizing glasses provide every other line to each eye).
10) Interestingly, any kind of 3D content on a computer is a candidate for viewing on a stereoscopic monitor. We’re still in the alpha stage, so there are too many bugs and incompatibilities to count, but there are a number of great implementations of specific games. For instance, you can play World Of Warcraft, and a dozen other games, on any 3D screen or monitor. Nvidia makes a stereo driver, and iz3d provides drivers for their 3D gaming monitors.
Instead of damning with faint praise, people are praising the new generation of 3D with faint damnation: “It doesn’t hurt as much to watch 3D anymore”. While hardly a glowing endorsement, if you haven’t tried out passive 3D - in a movie theatre, you shoud.
If you haven’t seen 3D with passive glasses, you really should. I have tried shutter glasses and unfortunately my brain doesn’t buy the trick; it gets annoyed that something is being pulled over my eyes 30 times per second. The passive glasses, however, I find very fun.
The best in-theatre stereo I’ve ever experienced is at Walt Disney World, Magic Kingdom, the Mickey’s PhilharMagic movie. It has Donald duck following a string of Disney Princesses. My 5-year-old daughter literally stood up and reached out to try to grab floating jewels, and that kind of visceral reaction means that the technology is working.
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