Engineers at UC Santa Cruz have developed a 3D+2D television that that combines both 2D and 3D, allowing viewers with stereo glasses to see three-dimensional images, while viewers without the glasses see a normal two-dimensional image without blurriness.
With existing 3D television displays, viewers must wear stereo glasses to get the effect of seeing images on the screen in three dimensions, while viewers without the glasses see a blurry image. That’s because the 3D TV shows a different image to each eye through the stereo glasses, and a viewer without the glasses sees both images superimposed, resulting in “ghosting.”
James Davis, associate professor of computer science in the Baskin School of Engineering at UC Santa Cruz, who led the project, developed the new technique with UCSC graduate students Steven Scher, Jing Liu, Rajan Vaish, and Prabath Gunawardane. His team will present their 3D+2D TV technology at SIGGRAPH 2013, the 40th International Conference and Exhibition on Computer Graphics and Interactive Techniques, on Thursday, July 25, in Anaheim.They have also described it in a paper in the June issue of ACM Transactions on Graphics.
Davis’s 3D+2D TV shows separate left and right images when viewed through glasses, but those without glasses see only the left image. The system also displays a third image, which is not seen through either lens of the glasses. The third image is the negative of the right image–bright where the right is dark, and dark where the right image is bright–canceling out the right image so those without glasses see only the left image.
With this simple version of the system, 2D viewers see a low-contrast image, because the darkest pixel is relatively bright. To restore acceptable contrast to 2D viewers, the researchers allowed the images seen by the left and right eyes of 3D viewers to have unequal brightness, where the left becomes brighter and the right dimmer. Then they conducted several experiments to determine the optimal brightness ratio between right and left images. They found that brightness ratios in the range between 20 percent and 60 percent were acceptable for viewers both with and without glasses.
Their findings indicate that the Pulfrich effect is not an obstacle to using unequal brightness for right and left eyes in a 3D+2D TV. In fact, they found that the virtual time delay of the Pulfrich effect can be used to cancel the effect of the actual time delay in a sequential-frame stereo display.
Publication: Steven Scher, et al., “3D+2DTV: 3D displays with no ghosting for viewers without glasses,” ACM Transactions on Graphics, Volume 32 Issue 3, June 2013, Article No. 21; doi:10.1145/2487228.2487229
Source: Tim Stephens, UC Santa Cruz
Image: J. Davis