Electronic Design

Several Kinds Of 3D Systems Are Gaining Momentum

There's no doubt that in the near future, 3D systems will hit many different venues. Less clear is which type will dominate. There's also much confusion about what's meant by 3D. For example, some think rendered 2D images can qualify as 3D. On the other end of the spectrum, devices that create voxels, or volume pixels, are considered by some as the ultimate 3D system. Several other types of 3D displays systems lie in between, with stereoscopic as the most popular.

Stereoscopic 3D presents slightly different perspectives of an image, a left and a right eye image, so the viewer sees a small difference in parallax, which creates the illusion of 3D imagery. These left/right eye images can be created with a special 3D camera, or else be generated from standard 2D imagery by various techniques.

Stereo images can be delivered directly to an immersive or semi-immersive headset with twin displays. Alternatively, the stereo image pairs can be displayed on a monitor or projected onto a screen. Many systems require the assistance of some glasses to see the stereoscopic image pairs, which are typically displayed in sequential fashion. This "eyeware" comes in two varieties, active and passive.

The passive glasses usually contain polarizers that transmit images to the proper eye. The active glasses, sometimes called shutter glasses, contain a liquid-crystal display element that transmits the left or right eye image and is synchronized to the projector or monitor.

StereoGraphics, San Rafael, Calif., just introduced its latest wireless, stereoscopic product, called CrystalEyes 3. It features enhanced stereo sync circuitry and 50% better battery life, allowing more than 250 hours of continuous operation.

An autostereoscopic system requires no glasses at all. Several methods exist to create images at slightly different output angles, so the eye can perceive the two images naturally. One method is to present the left and right eye images on alternating columns of a display. Using a lenticular screen, the images from all of the odd columns, for example, exit the display at a slightly different angle than the even columns. It's designed to allow each eye to see these images independently, creating the 3D effect. Such displays, however, often create "zones" of viewing that are discontinuous as one moves around the room.

But, New York University reports that it has developed an autostereoscopic display that eliminates the discontinuous zones. The system creates a dynamically varying parallax barrier, which continually changes the width and positions of its zones as the observer moves.

VisuaLABS, Alberta, Canada, has a 3D technology that isn't stereoscopic. Instead of producing left and right eye images, each pixel is encoded with depth information and displayed at up to eight different apparent depths from the viewer. Depth cues can be generated with a special camera or added to existing 2D material on a frame-by-frame basis, much like colorizing a movie.

A new concept for 3D vision comes from Nippon Telegraph and Telephone Corp., Tokyo, Japan. Recently, the company completed a prototype 3D display in which an impression of depth is created by projecting and overlaying the same image at different levels of brightness. The system doesn't require special lenses and provides the viewer with a more natural 3D effect than existing displays.

These developments, and many more, point out the huge potential that they represent for entertainment, e-commerce, scientific, and business applications.

TAGS: Components
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