What is the principle of red and blue filtration?

The reason why human vision can distinguish distance is because of the difference between two eyes. People's eyes are about 5 cm apart, and nothing will have the same angle except aiming straight ahead. Although the gap is very small, it is transmitted to the brain through the retina, and the brain uses this tiny gap to generate the depth of distance, thus creating a three-dimensional sense. Although one eye can see objects, it is not easy to tell the distance between them. According to this principle, if the same scene is made into two images by using the difference between the two eyes, and then each eye sees its own image on one side, the depth of field can be stereoscopic through the retina. Various three-dimensional demonstration technologies also use this principle, which we call "polarization principle".

IMAX's 3D movies are made by the principle of polarization. At the same time, two cameras are used to shoot images of the scene from different angles at the same time. During screening, two sets of films shot by two cameras are simultaneously screened by two projectors with polarized lenses, so that two slightly different images are overlapped on the screen. The light output by a film projector becomes polarized light after passing through a polarizer, and the projector is usually equipped with a vertical polarizer. The polarized glasses used by the audience are actually a process of restoration. Imagine a scene: there are two movie projectors with polarized lenses behind you. After wearing polarized glasses, the left eye can only see the images played by the left-hand projector, and the right eye can only see the images played by the right-hand projector. Combined with the "polarization principle", we can see movies with strong three-dimensional sense.

According to the principle of red and blue filter, it is also very convenient to make movies by using this stereoscopic imaging, and its biggest advantage is that it is not limited by existing imaging equipment, and you can experience almost perfect stereoscopic effect as long as you match a pair of red and blue filters. In the past, some media playback software, such as the 3D version of Oriental Cinema, achieved stereoscopic effect through interpolation, which was actually a red and blue filter.

1. It is best to use a red-blue mirror with a heavy color depth, and the red-blue virtual shadow at the edge of the scene can be almost completely filtered out. In addition, the original color of the film is the best. 2. The red-blue mirror with lighter color depth has a slightly poor effect and a slight ghost problem. The original tone of the film is slightly poor, but the effect is acceptable. 3. The dark red-green mirror has the same effect on the projector, but it is more suitable for close-up viewing on TV and high-brightness display equipment. 4. Light red-blue mirror and red-green mirror failed the most.

Under the current equipment conditions, it is impossible to watch stereoscopic movies based on the principle of polarizer at home, although its effect is the best, unless you use two imaging devices equipped with polarizers, two DVDs shot from different angles, and professional playback equipment and synchronizer. The 3D movies with red-green filter or red-blue filter should become the mainstream of home theater, and the movies made with this filter principle are completely compatible with our current home audio-visual playback system.