A novel design for 3D display in a cinema setting makes 3D viewable at high resolution and without the need for special eyewear. The prototype design, dubbed Cinema 3D, allows viewers to experience the same 3D effects from any seat in the theater. Whereas current displays for glasses-free 3D viewing attempt to cover a wide angle of view, which diminishes resolution, Cinema 3D delivers a narrow range of images to each individual seat in the house. A new prototype display could show 3D movies to any seat in a theater, with no eyewear required. Courtesy of Christine Daniloff/MIT. Researchers from Massachusetts Institute of Technology and Weizmann Institute of Science observed that a viewer in a cinema seat could only change their view of the screen within a tiny subset of angles limited by the width of their seat. Based on this observation, they designed a display that presented a narrow range of angular images across a small set of viewing positions from a single seat, and replicated the same narrow angle content for all seats in the cinema. Using this approach they were able to reduce the number of images that needed to be displayed, enabling higher spatial and angular resolution over each seat. They were also able to simplify content generation, since fewer images were required for the display. A key challenge was making the display work for viewers at different distances from the screen. Knowing that viewers observe the screen from different angles, the researchers constructed a structure similar to a cross-slits camera, with two layers of barriers that steered the rays from each pixel to each row of viewers, achieving equal parallax at all screen distances. Although glasses-free 3D exists, current methods do not scale well to movie theaters. Traditional methods for 3D TV sets use a parallax barrier to create 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 where the screen is viewed from different angles and distances. Cinema 3D encodes multiple parallax barriers in one display, so that each viewer sees a parallax barrier tailored to their position. The viewing range is replicated across the theater using an array of mirrors and lenses to make 3D viewable from many angles. "Existing approaches to glasses-free 3-D require screens whose resolution requirements are so enormous that they are completely impractical," said MIT professor Wojciech Matusik. "This is the first technical approach that allows for glasses-free 3D on a large scale." "With a 3-D 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," said Gordon Wetzstein, an assistant professor at Stanford University who was not involved in the research. "The authors [of Cinema 3D] cleverly exploited the fact that theaters have a unique setup in which every person sits in a more or less fixed position the whole time." Although the current prototype requires 50 sets of mirrors and lenses for a size that is barely larger than a pad of paper, the team has demonstrated that their approach allows viewers from different parts of an auditorium to see images of consistently high resolution. 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 3-D for large spaces like movie theaters and auditoriums." The research was presented at SIGGRAPH 2016 International Conference and Exhibition on Computer Graphics & Interactive Techniques. Cinema 3D: A movie screen for glasses-free 3D. Courtesy of MITCSAIL.