While the
announcement from the Blu-ray Disc Association (BDA) yesterday indicated that they were still examining candidates for implementation of 3-D on Blu-ray, moves by two primary Blu-ray companies - Sony and Panasonic - have given a glimpse into the future of Blu-ray: Active Shutter 3-D.
3-D presentations work by giving distance to otherwise flat images. Two visual perspectives are presented which, when combined, give distance to the image in the same way your eyes gauge distance. Try this: Hold a pencil a few inches from your nose. If you cover your right eye, the pencil will appear to be to your right. Cover your left eye and the pencil moves to your left. When your brain combines these two perspectives, it gives you a sense of distance – the third dimension. With film, two perspectives are presented to the viewer, and when combined, simulate distance. Thus, a 3-D effect.
You are likely most familiar with anaglyph 3-D presentations that require viewers to wear the now iconic red/blue glasses. The tinted lenses of the glasses act as color filters, restricting certain parts of the image specific to each visual perspective from reaching the viewer's eye. By presenting two different perspectives of the image to each eye, the viewer perceives a 3-D image.
Today, the majority of 3-D films are presented theatrically with an evolved version of the red/blue glasses which uses polarization to block images rather than color filters. Two polarized images are superimposed on the screen, one for the left eye and one for the right eye. Through polarization, the glasses allow each eye to only see the perspective intended for that eye. Similar to the red/blue presentations, two different visual perspectives simulate distance in the image.
While both the red/blue and polarized solutions are inexpensive, difficulties arise outside of ideal settings. If viewed at an angle or in lighter settings, the 3-D effect diminishes rapidly. In the home theater setting, it is unlikely that the majority of users watch films in the ideal settings, so an alternative was developed: active shutter technology.
Unlike the passive solutions described above, active shutter glasses literally block and unblock your view utilizing remotely activated LCD screens in the lenses. Here's how it works: Your HDTV sends a signal (via IR, Bluetooth, or other radio transmitters) to the glasses to sync them to the correct frame rate. The glasses - which are powered by rechargeable batteries - will send alternating electrical signals to each lens which activates an LCD screen in the lens, effectively blocking that eye's view of the screen.
At this same time, the HDTV is alternating visual perspectives (called "alternate-frame sequencing") at the exact same rate. When the right eye is blocked (and the left eye is viewing), the left perspective is displayed. When the left eye is blocked, the right perspective is displayed. By alternating visual perspectives to each eye it gives the perception of a 3-D image. And this all happens so fast, that you never realize your vision is being blocked.
If this all sounds too futuristic, you might be surprised to learn that it's being used commercially today. The main provider of this technology is
XpanD, and they have installed these active shutter 3-D systems in many theaters across the globe (including the screening theaters for the majority of Hollywood studios). The glasses run about $100 a piece, which should reduce as consumer interest rises.
Panasonic has been
parading their 3-D Blu-ray solution around the world since it was
first revealed at CEATEC 2008, which features a 3-D plasma HDTV, a 3-D Blu-ray Disc player, and active shutter 3-D glasses. Likewise, Sony has recently announced their intention to integrate 3-D across their entire home entertainment line using active shutter technology.
Officially, the BDA has yet to bless active shutter 3-D technology as the delivery mechanism for 3-D Blu-ray, but with two top Blu-ray companies now on board, there can be no doubt that when a decision is eventually made, it will be in favor of active shutter 3-D.