Holography is the science and practice of making holograms. Typically, a hologram is a photographic recording of a light field, rather than of an image formed by a lens, and it is used to display a fully three-dimensional image of the holographed subject, which is seen without the aid of special glasses or other intermediate optics. The concept was invented by Dennis Gabor.
Researchers at the University of Southern California’s ICT Graphics Lab have created a new type of holographic display that can generate simultaneous 3D views for multiple observers without the need for special glasses. The setup also happens to be relatively inexpensive since it’s built around a specially modified off-the-shelf DLP projector that works with a spinning mirror.