How about a glasses-free 3D movie experience?

Scientists have come out with a display that lets audiences watch 3D films without extra eyewear

Movies in the 3D format take us to new worlds and allow us to see places and things in ways that we otherwise couldn’t. But behind every 3D experience is something that is uniformly despised: those goofy glasses.

Fortunately, there may be hope. In a new paper, 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 theatre without extra eyewear. Dubbed ‘Cinema 3D’, the prototype uses a special array of lenses and mirrors to enable viewers to watch a 3D movie from any seat in a theatre.

While the researchers caution that the system isn’t currently marketready, they are optimistic that future versions could push the technology to a place where theatres would be able to offer glasses-free alternatives for 3D movies.

Glasses-free 3D already exists, but not in a way that scales to movie theatres. 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 theatres 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 theatre.

What Cinema 3D does, then, is encode multiple parallax barriers in one display such that each viewer

DUBBED ‘CINEMA 3D’, THE PROTOTYPE USES A SPECIAL ARRAY OF LENSES AND MIRRORS TO ENABLE VIEWERS TO WATCH A 3D MOVIE FROM ANY SEAT IN A THEATRE

sees a parallax barrier tailored to their position. That range of views is then replicated across the theatre by a series of mirrors and lenses within Cinema 3D’s special optics system.

However, 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. Matusik says the team hopes to build a larger version of the display and to further refine the optics to continue to improve the image resolution.