What's the difference between 3d movies and 3d holographic projectors? What technology are both used?

D is the prefix of English Dimension, and 3D refers to three-dimensional space. Internationally, 3D movies are used to represent stereoscopic movies. There are many forms of making 3D stereoscopic movies, among which polarized glasses method is widely used.

although one eye can see the object, it is difficult to tell the distance between the objects. According to this principle, if the same scene is made into two images with the difference of the visual angles of two eyes, and then the two eyes can see their own images one on each side, the depth of field can be stereoscopic through the retina.

during screening, two films are loaded into the left and right film projectors respectively, and two polarizers with polarization axes at 9 degrees are respectively installed in front of the projection lens. The two projectors need to run synchronously, and at the same time project the picture on the metal screen to form a double image of the left image and the right image. When the audience wears special polarized glasses, the polarization axes of the left and right polarizers are perpendicular to each other and consistent with those in front of the projection lens; The left eye of the audience can only see the left image and the right eye can only see the right image. The left and right images are superimposed on the retina through the binocular convergence function, and the brain nerve produces a three-dimensional visual effect. Show a continuous three-dimensional picture, so that the audience feels that the scenery is coming, or entering the deep recess of the screen, which can produce a strong sense of "being there".

The holographic projection technology is the reverse display of holographic technology, which essentially forms a three-dimensional image on air or a special three-dimensional lens. Different from flat screen projection, which only realizes stereoscopic effect on two-dimensional surface through perspective and shadow, holographic projection technology is a real 3D image, which can view different sides of the image from any angle of 36.

this is an advanced optical technology, which is still in the research and testing stage.