What technology is used in the 3D stereoscopic image presented in the Spring Festival Evening? What technology was used to realize the five rings floating in the air in the 2008 Olympic Games?

3D image technology is based on the principle that the parallax formed by the pupil distance between the left and right eyes in the brain produces stereoscopic effect. Two different images are projected on the screen, and the viewer can see two consecutive images through the left and right eyes respectively, thus making the viewer feel immersive, which forms a stereoscopic image.

There are many ways to realize stereoscopic images, and the most common one is the polarization principle of light. When shooting a three-dimensional movie, two cameras are used to shoot synchronously with the angle difference between people's eyes. As we know, a light source becomes polarized light through a polarizer, which can only be seen through a lens with the same polarity. During screening, different polarizers are placed in front of two film projectors (or digital projectors) to obtain two kinds of polarized light in the vertical direction. One projects transverse light and the other projects longitudinal light. The audience sees two synchronized pictures from different angles through polarized glasses, which are transmitted to the brain to form a three-dimensional picture of far and near levels.

I haven't been to the field to see the naked-eye 3D technology of the Spring Festival Gala, so I don't know much about it. Whatever it is, it should not be seen at the scene, and it needs two cameras to shoot at the same time.