Holographic video

NHK is developing a holographic TV that doesn't require viewing glasses (via Reddit.)

The premise is simple: put a transparent surface between the viewer and the object. All the viewer sees is the photons coming from the transparent surface. Now sustain the photon emission from the transparent surface as-is and remove the object. To the viewer it looks like nothing has changed. The object seems to be still visible through the surface and you can walk around and look at it from different angles. A hologram! (When I understood the idea, I got a stupid goofy grin and walked around the house going all "WOOHOO! HOLOGRAMS! YEAH!")

Implementation then. The camera lens could be a large sheet of viewing-angle-optimized hemispherical pixels with an RGB light detector for each direction. The viewing device would swap the detectors for emitters. It'd require a huge lens (the size of the display, really) and require multiple times the megapixels of the usual one-directional image (as now each pixel is in fact several pixels, each facing a different direction.)

Except that they're not doing it quite like that. I don't fully understand it, but I think they're using an 2D array of lenses to get a flat projection and then record the resulting 2D image in the usual manner (project to a small CCD/CMOS/whatever). The display is a regular ultra-high-resolution flat panel with a similar array of lenses in front of it. Here's a good presentation slide deck: 3D-TV System Based on Spatial Imaging Method for Future.