The Future of Cinema - 'Real' 3D

GunSlinger writes "The IGN movies site is running a story on an old movie concept seeing a resurgence. 3D movies are making a cinematic comeback via new, more sophisticated techniques. Yes, you still wear glasses. No you don't get a headache. Yes, the effect is fantastic. This story looks at the technology, past and future projects, and why just about every major studio is now planning in three dimensions. 'There is indeed a revolution in cinema taking place. It's quietly slipped under the radar of most technophiles, beginning its assault on the way we consume media clothed in thoroughly unassuming garb -- the Disney Digital 3-D film, Meet the Robinsons ... no, we don't blame you for being skeptical. Most people in their mid-20s or later think of 3-D movies from the old school perspective -- goofy red and blue coloured glasses, strained eyes, possible migraines. And most importantly, a so-so 3-D effect. No more.'"

Comments

RTFA, they claim to solve that

[Mr2001]

Forget the ancient red and blue though, as Real D uses "a specially polarized type of eyewear called circular polarized lens, which is very different from traditional 3-D in that it allows you to tip your head without losing the 3-D effect -- something you can't do with typical 3-D systems."

Don't second guess if you haven't seen the movie!

[McVerne]

I saw Meet the Robinsons in 3D the other week.

Shoddy glasses?
The glasses were not paper/cardboard. They looked like plastic sunglasses.

Already wearing glasses?
I wear corrective glasses and the 3d glasses fit fine over them.

Can't move your head?
No, you don't have to keep your head still. You can turn your head without bluring or motion sickness.

The 3d effect is stunning. This is miles beyond the old cardboard red/blue glasses.

--McVerne

Technique overview

[chenjeru]

There are a few major approaches being used right now. They all come down to delivering a different image for the left and right eyes. The system in TFA uses a combination of circular polarization and frame sequential techniques. Here are the major techniques currently used:

Frame sequential
_This uses a single projector or screen with a high framerate, 120Hz or higher. Each frame alternates between a left and right eye view. The viewer wears a pair of LCD 'shutter glasses' which are synchronized to flicker and allow only the correct frame through per eye. Thus, a 120Hz output becomes a 60Hz image stream to the viewer. Unfortunately, the glasses are expensive and not easy to deploy to a large audience. This technique also often causes headaches after extended viewing.

Head mounted display
_Funky goggles are used to provide a dedicated image for each eye in close proximity. Advantages include the ability for head tracking which provides parallax shift and real immersion. The units are also localized to the wearer, so you can have them in small spaces like cockpits. Disadvantages: relatively low resolution and expensive for large deployments.

Linear polarization
_Using 2 projectors (usually DLP) which have linearly polarized filters in front of the lenses, one has left-right polarization for one image and the second an up-down polarization for the other eye. The user wears paper glasses with lens orientation corresponding the the projector output. This technique is easiest to deploy to large audiences since the paper glasses are relatively cheap. However, the 3D effect can be broken by rotating the head.

Circular polarization
_Similar as the linear approach, filters are used in front of 2 projectors creating left-right images. The filters used for the projectors and glasses are circularly polarized which allows head rotation, but suffers from 'ghosting' or 'image bleed' since the circular polarization does not block all light intended for the other eye.

Chromatic filtering
_Similar to the old red and blue glasses from yesteryear, this technique uses spectrum filtering to restrict certain wavelengths from reaching each eye. When used with filters in front of 2 projectors, dedicated left-right images can be created. The newer techniques use more controlled filtering so that the color aberrations are minimized.

Lenticular
_Using a special vertically banded lenticular lens in front of a back-projection screen or TFT/Plasma, this technique creates 'zones' in which 3D images can be seen without any hardware required on the viewer. By shifting your head left or right, you fall into viewing 'sweet-spots'. This is based on the fact that a human's eyes are generally spaced the same distance apart. One of the great things about this approach is that since there are images from multiple camera angles being displayed simultaneously, you can actually get a little parallax before falling out of a sweet-spot. You'll see this technique more and more at trade shows and in public advertisements.

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