In many American movies, we often see this scene: the protagonist gently waves his hand, and a display screen appears out of thin air in front of us. Not only can the content on the screen be switched at will, but it can also be used to achieve face-to-face conversations with people thousands of miles away. This is holographic projection technology. As a new black technology, holographic projection is receiving more and more attention!

1. Is the virtual image on the stage holographic?

The most common holographic projection is seen at various concerts. In 2010, the famous Japanese virtual idol Chuyin appeared at a concert through holographic projection technology. Although the technology at that time was not mature enough, the emergence of stereo initial sound attracted widespread attention. The effect change from 2D to 3D seriously affected the neurons of a group of otakus. Similar techniques are now widely used on stage and appear to be a technical touch. Many people call it "holographic projection". Unfortunately, these are not holographic projection technologies. Their real name is Purber Illusion. Although it has a similar effect to holographic technology, it is still different from real "holographic projection".

2. Pepper's illusion:

This is a clever optical illusion technique, and its principle is not complicated. When light hits the real performers, the virtual image in the image above is created by mapping specific areas on the stage through the glass. This is the imaging process of the Perber illusion. Now, thanks to CG technology and high-brightness lighting, Pepper's hallucinations are brought to life.

3. What is holographic projection technology:

The first step is to use the interference principle to record the light wave information of the object. This is the shooting process. Irradiate the object with a laser to form a diffuse object beam; use another part of the laser beam as a reference beam to shoot on the hologram. The hologram overlaps with the object beam to generate interference, converting the phase and amplitude of each point on the object's light wave into space. in order to record the contrast between interference fringes and all the information about the light waves between objects. The negative film recording the interference fringes becomes a hologram after development, fixation and other processes, which is called a hologram. In the second step, the hologram acts like a difficult grating. Under the irradiation of laser, the light wave of the sinusoidal hologram can produce two images, namely the original image (also called the initial image) and the yoke image. The reconstructed image has a strong three-dimensional sense and realistic visual effects. Each part of the hologram records light information from each point on the object. Therefore, in principle, each part of the hologram can reproduce the entire image of the original object. With multiple exposures, several different images can be recorded on the same negative and interference can be revealed.