Thursday, July 28, 2011

#3D: "Smarter 3D Employs Eye Tracking"

LG claims to have solved the problems with glasses-free 3D displays with a smarter eye-tracking technology that adapts to the viewing angle of the user. Available this fall in a 20-inch monitor, the smarter 3D solution eliminates the need for glasses and is compatible with normal 2D imagery.

Glasses-free 3D displays, called auto-stereoscopic displays, have in the past depended on lenticular lenses that fit over displays to divert separate images to the right and left eyes. Unfortunately, lenticular lenses scramble regular 2D images. Parallax barriers are an alternative to lenticular lenses, but they do not provide a wide variety of viewing angles. LG has solved this last remaining problem with smarter eye-tracking technology that adapts the parallax barrier as the viewer's head moves.

Parallax barriers work similarly to lenticular lenses in that they divide an image into alternating stripes for the left- and right-eye. However, instead of using a lens to bend the alternating stripes to the correct eye, a parallax barrier uses a second layer of alternating clear and black lines to block the left-eye stripes from reaching the right eye, and vice versa. The brain fills in the gaps between stripes, resulting in completely separate images reaching the correct eyes without the need for lenticular lenses or 3D glasses.

Unfortunately, the tiny parallax-barrier stripes must be precisely located in order to correctly block the right-eye stripes form the left eye and vice versa. Thus in the past, parallax-barrier displays have only been successful with smaller screens like cell phones where users keep their heads centered on the screen anyway. However, larger displays did not work well with parallax barriers, because users are much more likely to move their heads out of the correct central location.
LG's solution was to add an eye-tracking camera that adjusts the parallax barrier so that it reliably diverts the left- and right-eye stripes to the correct eye even for users moving their heads.

The application of LG's smarter glasses-free 3D technology will be in its new 20-inch wide D-2000 display. The only major limitation is that it can only track the location of a single user's eyes. Thus the technology is not appropriate for TVs where multiple users may be watching from different angles. However, for single users, LG's smarter eye-tracking technology solves all the problems associated with auto-stereoscopic 3D displays and is suitable for still images, movies and gaming. The display also has a built-in conversion capability that adds some degree of 3D to 2D movies and games (but not still images).
Further Reading