answer:All 3D imaging on a flat display, whether it’s a movie screen or a TV screen, works in much the same way. Two images are superimposed on one another, and the viewer wears a pair of glasses that suppresses one of the images for each eye. Early 3D films like “Creature From the Black Lagoon” were shot in black and white, with depth information added through cyan and magenta highlights. A viewer wore red and green colored glasses when looking at the screen. The red lens filters the cyan light so that part of the picture looks black. The green lens filters the magenta light so it looks black. A little later, 3D films went to a system of polarized light. This allowed for true color on films like “House of Wax.” Light polarized in one plane is suppressed by lenses polarized in the other. 3D films shown on screens still work this way. 3D TV, however, relies on the fast refresh rate of the imaging device. Alternating frames of two separate images are shown on the screen. The viewer wears glasses that have liquid crystal shutters built into them, so each eye sees only the image that is synchronized with the shutter. This technology isn’t new. You could buy a VHS camcorder back in the 1990s that incorporated the technology, but the image for each eye had an effective frame rate of 15 FPS, which made the image look jerky. Lots of people get headaches from looking at 3D movies, regardless of the technology used. Older films not shot in 3D cannot be directly upconverted to 3D because only a single camera was used. However, computer graphics could simulate a 3D picture by using information from adjacent frames in a movie shot with a single lens, or by adding depth through signal processing. The process would not be perfect, but given the sophistication of techniques used for films like “Avatar,” they could probably come up with something pretty impressive. Any processing would have to take place at the studio, though. The TV set wouldn’t be able to do it.