Forget the funny glasses [autostereoscopic display systems]

Shutter glasses, polarized glasses, and head-mounted displays (HMDs) have become common technologies for providing the illusion of 3D. Shutter glasses, popularized by StereoGraphics as CrystalEyes, use an LCD shutter over each eye to enable stereo viewing. The shutters are rendered alternately opaque and transparent so that only one eye can see through the glasses at any moment. The glasses are synchronized to the display system presenting the right and left images at the same frequency as the shutters' phase shifts. These systems can work with televisions, computer monitors, or projectors, but require that the display system can generate images at twice the frequency desired for viewing, because each frame must be shown twice (once for each eye). Although they can cause some loss of image brightness and can suffer from crosstalk, shutter glasses work well and permit full-spectrum color. However, especially with low-cost systems, they can cause eyestrain and other discomfort. In addition, the eyewear is bulky and often heavy, which makes using shutter glasses for long periods of time somewhat uncomfortable. Autostereoscopic displays (ASDs) use several technologies to present different images to both of a viewer's eyes. Volumetric display systems (VDSs) create an image with true depth, letting the eyes and brainwork in natural manner. ASD and VDS systems are intended to replace current 3D displays, all of which require the user to wear some sort of filtering system, such as eyeglasses.