Breaking Down 3D Formats


DPI explains the three categories of 3D: Low Tech, Mid Tech and High Tech.

Mar. 18, 2010 — by .(JavaScript must be enabled to view this email address)

Extraordinary 3D is all about creating the best environment and equipping it with powerful 3D displays capable of delivering a truly immersive experience.

In the world of 3D entertainment, the believability of the experience is everything.

Let’s take a look at the more advanced levels of 3D display technology available for home use.

Low Tech: 3D via Anaglyph 3D
Due to the limited number of true 3D TVs currently in homes, the delivery of television-based 3D content has had to rely on the anaglyph 3D process.

Viewed in 2D mode, the images look like “double vision” with one image having a cyan tint and the other image having a red tint. Anaglyph content is viewed using matching glasses, which have a cyan filter as the lens for the left eye, and a red filter as the lens for the right eye.

Through the anaglyph viewing process, the cyan content is only seen by the viewer’s left eye and the red content is only seen by the viewer’s right eye. This is the simplest and least expensive 3D delivery method and provides the least dynamic 3D experience.

The cyan and red filters tend to distort the color accuracy of the 3D content. Thus, while anaglyph 3D technology does allow 3D content to be delivered to any television in any home, it is generally considered to provide a 3D experience that is far from state of the art.

Mid Tech: 3D DLP for TVs
The first 3D DLP consumer displays were introduced in 2007 as rear-screen single-chip TVs. Using the inherent speed of the DLP’s micro mirrors technology, the displays transmit left and right eye imagery separately for stereoscopic imaging with high-quality 3D glasses.

Consumer-level 3D DLP TVs enlist a specific technology referred to as checkerboard imaging. For example, the red squares of the checkerboard represent the right eye, and the black square represents the left eye. In this fashion, full 1080p images can be displayed without the need for expanded bandwidth.

The images are displayed 60Hz right eye and 60Hz left eye (equivalent to 120Hz). Since every other pixel is dedicated to either the left or the right eye, the resolution of each single eye image is only half the native resolution of the 3D television. While this does sacrifice image quality, no additional system bandwidth is required to support signal distribution.

The high-speed LCD shutter glasses allow the appropriate left eye information to transmit to the left eye and right eye information to transmit to the right eye. Thus, total left and right eye signal can equal full 1920 x 1080, if that is the native resolution of the 3D TV.

High Tech: Active 3D Projectors
The latest 3-chip 3D projectors use a more advanced technology capable of supporting full Active 3D whereby a 120Hz signal is fed to the projector (full 1920 x 1080 60Hz, left; full 1920 x 1080 60Hz, right), and the right eye and left eye are displayed sequentially. Once again, high-speed LCD shutter glasses are used and synchronized with the projector via an IR emitter, blocking the right eye when left eye content is displayed, and vice versa.

The signal requirement is that you either need a high-speed dual link DVI cable to transmit 120Hz full HD signals to the projector from the source or two standard DVI/HDMI cables - one for the right eye content, one for the left eye content.

HDMI 1.4 looks to reduce this to a single cable. Due to the high speed of the 1920 x 1080 signal at 120Hz, extra care must be taken in cable bandwidth, connections, crimps and bending so as not to introduce bit errors.

There are several DLP two-piece consumer projection systems and flat-panel displays that advertise 3D capability, but they do so only at reduced resolutions. By reducing the resolution, the electronics and response times are greatly simplified. Most gaming flat panels are maximum 1680 x 1050, and many of the single-chip 3D projectors present a maximum of 1024 x 768 resolution.

There are a number of ways to create 3D with DLP systems. There are also numerous ways of generating 3D material, so the possible outcomes are limitless!

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