3-D HDTV is starting to get more in focus

As 3-D versions of movies continue to attract an audience, it’s inevitable that film studios and consumer electronics companies want to duplicate the success at home. The time is at hand, with Sony and Panasonic recently announcing a new advanced generation of 3-D TV products that should be available within the next year in the United States.

"Technology exists today that can make great quality 3-D experiences in the home," said Rick Dean, chairman of the 3-D@Home Consortium, a group of companies cooperating on strategies and standards for 3-D TV.

But up until recently, the production and viewing of video in 3-D hadn’t changed much since the 1950s when 3-D movies such as "House of Wax" and "Creature from the Black Lagoon" lured viewers away from their TVs and back into the theaters, along with goofy-looking glasses.

The glasses — with red-and-green lenses, infamous for inducing headaches and nausea — are used to view a type of 3-D process called "anaglyph." The stereoscopic effect, which gives 3-D video the illusion of depth, comes from two superimposed images, one green and one red, depicted from slightly different perspectives. Each of the viewer’s eyes sees the opposite colored image.

3-D movies currently available on DVD and Blu-ray — including "Coraline," "My Bloody Valentine" and "Journey to the Center of the Earth" — use anaglyph 3-D with cardboard red-and-green lens glasses, and are viewable on any TV.

"In order to see stereoscopic 3-D you need to send a right-eye view to the right eye and a left-eye view to the left eye," said Robert Boudreau, technology development manager for display commercial technology at Corning, a supplier of glass for LCD TVs. "The 3-D effect is created in the brain once the person’s eyes see these two views."

Much-improved process
Anaglyph 3-D is often underwhelming, especially for viewers used to high-definition, 2-D material. Then there are those unpleasant sensations.

While anaglyph is available in 1080p resolution, such as the "Hannah Montana" concert Blu-ray disc, "it does strain the eyes because each eye sees different colors and it is often difficult for people to view this type of 3-D, especially if they have a dominant eye," said Boudreau.

If you've seen a 3-D movie in the theater recently, the massive leap in color fidelity and dimensional effects compared to anaglyph films is due to a newer 3-D process that uses polarized glasses and a special theater screen. Projected images for the right and left eye are alternated rapidly and the polarized glasses pick up the correct image for each eye.

A related polarization technology called X-pol (for "cross-polarization") is now available in 3-D LCD high-definition TVs from Hyundai in Japan and LG Electronics in South Korea. The polarized glasses separate images for the right and left eye from the even and odd horizontal lines of video.

The DDD Group of California developed the TriDef conversion processor chip to convert 2-D video and games into 3-D for Hyundai’s 3-D LCD TVs.

There’s no contest, said Chris Yewdall, head of the DDD Group, when "comparing the latest Hyundai 3-D LCD TVs with full color Blu-ray Hollywood content, to the old-fashioned red/blue 3-D played back from a Blu-ray on a standard 2-D HDTV. ... It’s like comparing black-and-white TV to color TV."

'Active shutter' technology
Both Panasonic and Sony are backing yet another 3-D technology known as "active shutter," referring to the glasses used to view the 3-D video.

Left- and right-eye images are synchronized with the LCD shutters on the glasses by a signal sent from the TV. The LCD shutters quickly block out left- and right-eye views so that each eye sees only the intended image in sequence. The technology works with both LCD and plasma HDTVs.

The active shutter approach has one critical advantage over polarized 3-D: higher resolution.

Since polarized systems use filters to display only alternate lines of the video image to each eye, the vertical resolution is cut in half and image fidelity suffers. All the available screen resolution is used in active shutter products.

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