At Ceatec in Japan, NTT Service Evaluation Laboratories showed a prototype of a 3D Sand Table display; i.e. one in which participants can view a 3D image while walking around it in a tabletop format.
The tabletop has a special screen on it that is 1.1 m in diagonal and is designed to provide a 360º viewing window. Its surface is about knee high so that standing people can get a clear view. 60 projectors are arranged in a 3 m circle above and around the screen. Each Ricoh projector has ½ HD resolution and multiple projectors are designed to provide a series of views for any position around the display. This requires lots of cameras to acquire 360º views or the generation of the these views from a game engine for synthetic content.
It is a horizontal only parallax system that offers only about 5 cm of depth which is only mildly noticeable. As one moves around the table, most of the images are ghosting badly, so look like double images and you can see transitions from zone to zone at some points. Sticking you head in for a closer look mean you interrupt the projector light, thus blocking your view.
Overall, it is not that impressive in its current state, but would clearly be a lot better with more projectors with higher resolution. This will add fidelity and more depth. NTT also says they are working on an improved screen. – CC
