LED large screen moiré phenomenon elimination principle

"The principle of eliminating moiré phenomenon on large led screen" how to eliminate moiré on large led screen, the latest technology can solve this problem, with the development of LED screen technology, large led screen size, brightness, resolution, flexibility, display index, etc. In terms of technical breakthroughs, it has more competitive advantages than other types of display products, and has gradually become the mainstream display device on the stage. In the long-term use process, many friends will find that the large led screen will occasionally appear inexplicable water-like colors, which is the moiré phenomenon. What is the situation? The moiré phenomenon is a manifestation of the beating principle. When two patterns with spatial frequencies overlap, another new pattern is usually produced. This new pattern is usually called moiré. Since the camera's CCD (image sensor) target surface (photosensitive surface) is similar to the figure in the middle of Figure 2, and the LED large screen is composed of uniformly arranged dot matrix light-emitting tubes, the entire LED large screen has a large non-luminous area, forming a The grid-like pattern is similar to the image on the left of Figure 2, and the two overlap to form a moiré pattern similar to the right of Figure 2. Moiré is a manifestation of the beating principle, which is widely used in broadcasting, television and communications for frequency conversion and modulation. The main impact of the moiré phenomenon is on TV cameras. If the existing LED large screens have unbalanced light emission between pixels, poor imaging effects, and dazzling viewing at close range, moiré patterns will appear, which will affect the promotion and use of LED large screens in studios. Several methods to eliminate moiré. Elimination of moiré can be solved from two aspects of picture shooting and picture display. 1. Camera pixel offset technology The moiré phenomenon is caused by the fact that the image details are smaller than the interval between each image sensor. And the spatial bias improves the brightness level resolution of the CCD camera as much as possible. However, this method still cannot completely eliminate moiré, because the image sensor still has a certain spatial frequency and cannot be continuous into one surface. 2. Optical processing screen eliminates moiré. Through the optically processed LED large screen, the camera can shoot images without moiré at almost any angle, any position, and any focal length. The LED large screen with good optical processing, its brightness and color temperature meet the requirements of TV shooting, and there will be no moiré interference. At present, some manufacturers at home and abroad have mastered related technologies. A layer of optical treatment curtain is fixed on the surface of the LED large screen luminescent tube. At present, optical processing screen technology has been applied. The P2 small-pitch LED large screen designed and manufactured by Shanghai Sansi Company for Shanghai Qingpu TV Station is an application case. The optical processing screen must be close to the LED of the display screen; the optical processing screen uses a specific proportion of light-absorbing materials and microbead lens coatings to make it meet the requirements of TV photography in terms of light transmittance and color tone. This small-pitch LED large screen has high brightness uniformity, high saturation of color reproduction, and can improve color temperature and white balance; it can filter more than 90% of stray light. The image is clear, soft, and the colors are true to life, and the image is not distorted when taking close-up shots. The super-large viewing angle brings a very good visual experience to the audience. 3. Adjust the camera during shooting (1) Change the camera angle. Because the angle of the camera and the LED large screen will cause moiré, slightly changing the angle of the camera (by rotating the camera) can reduce or eliminate the moiré. (2) Change the focus, too clear focus and details on the detailed pattern may cause moiré, slightly changing the focus can change the clarity, and then help eliminate the moiré of the LED large screen. (3) Change the position of the camera, and change the angle relationship by moving left and right or up and down, which can reduce moiré. (4) Use software to eliminate moiré on the final image. However, the above-mentioned method can be applied in some specific occasions, but for television photography, especially for live television programs, there are practical operational problems. (5) Change the focal length of the lens, and use different lens or focal length settings to change or eliminate moiré on the LED large screen. .