Analysis of the difference between phantom imaging and holographic projection

Interactive projection system is an interactive advertising and entertainment system integrating the highest technology in the world today. Interactive audio-visual system provides an unusual and exciting advertising and entertainment effect system, which is suitable for all public indoor places, especially leisure, shopping, entertainment and education places. 20 13 virtual interaction technology has completed human-computer interaction, and there are many kinds of simulations with nature or virtual world. The response delay of interactive projection is less than 0.05 seconds, which is equivalent to similar products abroad and is in a leading position in China.

Principle of interactive projection system

The working principle of the interactive projection system is to capture and photograph the target image (such as the participant) through the capture device (sensor), and then analyze it through the image analysis system, so as to generate the action of the captured object. The combination of action data and real-time image interaction system makes the interaction effect between participants and the screen closely combined. The light projected by the projector is visible light, and its infrared part is filtered by its internal filter, so that the camera can't see the content projected by the projector. If infrared light is strong, the camera can see the human body. How to enhance the object image seen by the camera? Fortunately, infrared active emission technology is very mature in the market. For example, the night vision camera sold in the surveillance market can emit near infrared (850 nm), and there is a special long-distance infrared lamp, but the night vision camera can reach a distance of 5m, so it is not needed. The night vision camera actively emits infrared, and then the ccd sensor receives infrared, which solves the most difficult part of interactive projection, the segmentation of human body and background virtual objects, and the camera gets a black-and-white monochrome background image including people. Next, human motion is detected by image difference technology. The difference is that you subtract two consecutive images obtained by the camera, so what do you get? You get the moving part, so as long as people are moving, the difference will intercept the moving part. The next step is to analyze the data and then project the virtual part. Of course, complex interactive projection is not only these technologies, but also the most basic principles, which also involve camera calibration, optical flow method to find the direction of motion, performance optimization, special effects and so on.

Front projection holographic display

Front projection holographic display is a 3D technology, which originally refers to the technology of recording and reproducing real 3D images of objects by using the interference principle. Then, under the guidance of science fiction movies and commercial propaganda, the concept of holographic projection gradually extended to commercial activities such as stage performances and exhibitions. However, the holographic technology that we usually know is not holographic projection in the strict sense, but a holographic projection technology that uses pepper illusion and edge blanking to achieve 3D effect.

"Holography" refers to the inclusion of amplitude and phase information in light waves. Ordinary photography can only record the intensity information (amplitude) of light, and the depth information (phase) will be lost. In the interference process of holographic technology, the superposition of peaks will be higher, and the superposition of peaks and valleys will be flattened, resulting in a series of irregular stripes alternating between light and dark, thus converting phase information into intensity information and recording it on photosensitive materials.

Principle of holographic projection technology

The first step is to record the light wave information of the object by using the interference principle, which is the shooting process: the object to be photographed forms a diffuser beam under laser irradiation; The other part of the laser beam, as a reference beam, hits the holographic negative and interferes with the object light beam, converting the phase and amplitude of each point on the object light wave into spatially varying intensity, thus recording all the information of the object light wave by using the contrast and interval between interference fringes. Negative recording interference fringes become holograms, or holograms, after being developed and fixed.

The second step is to reproduce the light wave information of the object by using the diffraction principle, which is the imaging process: the hologram is like a complex grating. Under the irradiation of coherent laser, the diffracted light waves of linearly recorded sinusoidal holograms can generally give two images, namely the original image (also called the initial image) and the yoke image. The reproduced image has strong stereoscopic effect and real visual effect. Every part of the hologram records the light information of every point on the object, so in principle, every part of the hologram can reproduce the whole image of the original object. Through multiple exposures, multiple different images can be recorded on the same negative, and they can be displayed separately without interference.

Shanghai Xianzhi Industrial Co., Ltd. is a company specializing in the integration of multimedia creativity, planning and construction. Since its establishment, the company has been based on honesty, innovated with technology, survived with quality, served every customer with the concept of "user" as God, and guided by high-end technologies such as digitalization, three-dimensional animation, film and television shooting and human-computer interaction, and can provide professional multimedia solutions according to customer needs.

Since its establishment, the company has participated in many corporate culture exhibitions in national museums, planning museums, science and technology museums and large state-owned enterprises, and has a professional technical team and rich practical experience.

The company's core products include intelligent central control system, fusion splicing software, customized research and development of multimedia interactive software, large-screen touch interaction, VR, AR technology, stage lighting and sound design integration, and multimedia front-end display technology in the exhibition hall.