Automultiscopic display could enable glasses-free 3D cinema

Technical details published in a paper from the Massachusetts Institute of Technology Computer Science and Artificial Intelligence Lab (MIT CSAIL; Cambridge, MA), the Weizmann Institute of Science (Rehovot, Israel), and Saarland University (Saarbrücken, Germany) describe an automultiscopic display that would enable a comfortable, glasses-free three-dimensional (3D) viewing experience for cinema-goers. The developers caution, however, that the approach has not yet been deemed commercially viable.

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Dubbed "Cinema 3D," the prototype technology uses a special array of lenses and mirrors to enable viewers to watch a 3D movie from any seat in a theater. "Existing approaches to glasses-free 3-D require screens whose resolution requirements are so enormous that they are completely impractical," says MIT professor Wojciech Matusik, one of the co-authors on a related paper whose first author is Weizmann PhD Netalee Efrat. "This is the first technical approach that allows for glasses-free 3-D on a large scale."

While the researchers caution that the system isn't currently market-ready, they are optimistic that future versions could push the technology to a place where theaters would be able to offer glasses-free alternatives for 3D movies. The video below describes the technology:

The developers remind us that glasses-free 3D already exists, but not in a way that scales to movie theaters. Traditional methods for TV sets use a series of slits in front of the screen (a "parallax barrier") that allows each eye to see a different set of pixels, creating a simulated sense of depth. But because parallax barriers have to be at a consistent distance from the viewer, this approach isn't practical for larger spaces like theaters that have viewers at different angles and distances.

Other methods, including one from the MIT Media Lab, involve developing completely new physical projectors that cover the entire angular range of the audience. However, this often comes at a cost of lower image-resolution. The key insight with Cinema 3D is that people in movie theaters move their heads only over a very small range of angles, limited by the width of their seat. Thus, it is enough to display images to a narrow range of angles and replicate that to all seats in the theater.

What Cinema 3D does, then, is encode multiple parallax barriers in one display, such that each viewer sees a parallax barrier tailored to their position. That range of views is then replicated across the theater by a series of mirrors and lenses within Cinema 3D's special optics system. The team demonstrated that their approach allows viewers from different parts of an auditorium to see images of consistently high resolution.

Cinema 3D isn't particularly practical at the moment: The team's prototype requires 50 sets of mirrors and lenses, and yet is just barely larger than a pad of paper. But, in theory, the technology could work in any context in which 3D visuals would be shown to multiple people at the same time, such as billboards or storefront advertisements. The team hopes to build a larger version of the display and to further refine the optics to continue to improve the image resolution.

"It remains to be seen whether the approach is financially feasible enough to scale up to a full-blown theater," says Matusik. "But we are optimistic that this is an important next step in developing glasses-free 3-D for large spaces like movie theaters and auditoriums."

SOURCE: MIT CSAIL; https://www.csail.mit.edu/new_movie_screen_allows_for_glasses_free_3D_at_a_larger_scale