The best part of watching a movie in 3D is being able to see places and things in ways we otherwise couldn’t. The worst part is having to wear those awkward 3D glasses.
Fortunately, 3D movie glasses may soon become obsolete.
A team from MIT’s Computer Science and Artificial Intelligence Lab (CSAIL) and Israel’s Weizmann Institute of Science have demonstrated a display that lets audiences watch 3D films in a movie theater without the need for glasses.
Dubbed “Cinema 3D,” the prototype enables viewers to watch a 3D movie from any seat in a theater with no glasses required. The complex arrangement of lenses and mirrors creates a set number of parallax barriers (similar to Venetian blinds) which show a slightly different set of pixels to each of the viewer’s eyes to simulate depth, and can address every viewing angle in the theater based on seat locations.
“Existing approaches to glasses-free 3D require screens whose resolution requirements are so enormous that they are completely impractical,” MIT professor Wojciech Matusik, one of the co-authors on a related paper whose first author is Weizmann PhD Netalee Efrat, said in a statement. “This is the first technical approach that allows for glasses-free 3D viewing on a large scale.”
Not quite ready for cinemas
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. According to Matusik, the team hopes to build a larger version of the display and to further refine the optics to continue to improve the image resolution.
Other glasses-free 3D options
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Glasses-free 3D already exists, but not in a way that scales to movie theaters. Traditional methods for TV sets use a parallax barrier, a series of slits in front of the screen 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 involve developing completely new physical projectors that cover the entire angular range of the audience. However, this often comes at the cost of 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. The team demonstrated that their approach allows viewers from different parts of an auditorium to see images of consistently high resolution.
“With a 3D TV, you have to account for people moving around to watch from different angles, which means that you have to divide up a limited number of pixels to be projected so that the viewer sees the image from wherever they are,” Gordon Wetzstein, an assistant professor of electrical engineering at Stanford University, who was not involved in the research, said in an interview. “The authors of Cinema 3D cleverly exploited the fact that theaters have a unique set-up in which every person sits in a more or less fixed position the whole time.”
Among the paper’s co-authors are MIT research technician Mike Foshey; former CSAIL postdoc Piotr Didyk; and two Weizmann researchers that include Efrat and professor Anat Levin. Efrat will present the paper at this week’s SIGGRAPH computer-graphics conference in Anaheim, California. The team’s work was funded by the Israel Science Foundation and the European Research Council.
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. “It remains to be seen whether the approach is financially feasible enough to scale up to a full-blown theater,” said Matusik. “But we are optimistic that this is an important next step in developing glasses-free 3D for large spaces like movie theaters and auditoriums.”
Video: MIT, Weizmann Institute