Volumetric display

A volumetric display device is a graphic display device that forms a visual representation of an object in three physical dimensions, as opposed to the planar image of traditional screens that simulate depth through a number of different visual effects. One definition offered by pioneers in the field is that volumetric displays create 3D imagery via the emission, scattering, or relaying of illumination from well-defined regions in (x,y,z) space. Though there is no consensus among researchers in the field, it may be reasonable to admit holographic and highly multiview displays to the volumetric display family if they do a reasonable job of projecting a three-dimensional light field within a volume.

Most, if not all, volumetric 3D displays are either autostereoscopic or automultiscopic; that is, they create 3D imagery visible to the unaided eye. Note that some display technologists reserve the term "autostereoscopic" for flat-panel spatially multiplexed parallax displays, such as lenticular-sheet displays. However, nearly all 3D displays other than those requiring headwear, e.g. stereo goggles and stereo head-mounted displays, are autostereoscopic. Therefore, a very broad group of display architectures are properly deemed autostereoscopic.

Volumetric 3D displays embody just one family of 3D displays in general. Other types of 3D displays are: stereograms / stereoscopes, view-sequential displays, electro-holographic displays, parallax "two view" displays and parallax panoramagrams (which are typically spatially multiplexed systems such as lenticular-sheet displays and parallax barrier displays), re-imaging systems, and others.

Although first postulated in 1912, and a staple of science fiction, volumetric displays are still under development, and have yet to reach the general population. With a variety of systems proposed and in use in small quantities—mostly in academia and various research labs—volumetric displays remain accessible only to academics, corporations, and the military.

Many different attempts have been made to produce volumetric imaging devices. There is no officially accepted "taxonomy" of the variety of volumetric displays, an issue which is complicated by the many permutations of their characteristics. For example, illumination within a volumetric display can either reach the eye directly from the source or via an intermediate surface such as a mirror or glass; likewise, this surface, which need not be tangible, can undergo motion such as oscillation or rotation. One categorization is as follows:

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