autostereoscopic

Autostereoscopy refers to display methods that render three-dimensional images without the viewer wearing glasses. By presenting multiple slightly different views of a scene, the brain fuses them into a depth perception that changes with the viewer's position.

Most autostereoscopic systems rely on directing light so each eye sees a different perspective. Common approaches include parallax barriers, lenticular lenses, and integral imaging, as well as multi-view and head-tracking techniques.

Parallax barrier uses a physical mask that alternates visible image columns so each eye sees a different set of pixels. Lenticular displays place a sheet of tiny lenses over the image to route different views to different angles. Integral imaging stacks a microlens array over a 2D image to sample the light field. Multi-view systems render several fixed viewpoints and combine them depending on viewer position; some use head tracking to adapt the view in real time.

Advantages include glasses-free 3D and support for several viewers in some configurations. Disadvantages include limited optimal viewing zones, reduced effective resolution, potential crosstalk or ghosting between views, higher production costs, and content creation challenges.

Autostereoscopic displays have appeared in handheld consoles and some televisions, smartphones, and signage. The Nintendo 3DS is a prominent example, employing a parallax barrier to deliver glasses-free 3D. Ongoing research aims to increase viewing freedom, improve resolution, and reduce cost.