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How to eliminate the LED Video wall water ripple?

Source: Fengjiled  published:2018-4-10

Often we hear someone to consult us why at the scene to watch the large LED display screen is very clear, but use mobile phone or camera to shoot out. It was found that in the photo display screen there will be a kind of like water ripple on the screen, the entire LED screen is fuzzy, which will allow customers to LED display screen quality is very worried about that. What this kind of phenomenon is how to produce and how to deal with? 

To tell you, in fact, have lead to this phenomenon did not display their own reasons, but the photographer in the use of mobile phone and camera angle and focal length caused by. 

First, we need to understand the display on the wave pattern is what, as well as the distinction between it and the phenomenon of the scan line. 
1, it is also known as "moire". When we use the digital camera to shoot a scene, if there is a dense texture, often there will be a wave like stripes rather baffling. This is the mole pattern. In brief, the moire pattern is a kind of performance of beat principle. Mathematically, the two frequency is close to the equal amplitude sine wave superposition, the amplitude of the synthetic signal will be in accordance with the difference between the two frequencies. 
2, water wave pattern and the distinction between the phenomenon of the scanning line: 
wave pattern: the general appearance of irregular curved diffusion state! 
scan line: horizontal black stripes line, mainly due to the low refresh rate is captured by the camera to show! 

second, we want to understand the process of LED display to produce water ripple phenomenon. 
1, two spatial frequencies were slightly different stripes, they left the black line at the same position, due to the different intervals, to the right gradually streak line cannot coincide. 
2, two stripes overlap, because the left line overlap, so you can see the white line. On the right, white to black gradually staggered, overlapping results become black. There are white and black, composed of ripples. 
3, LED display pixel distribution density just between CCD can distinguish intervals, can avoid the digital camera will interpretation of the part can be used to identify the results, but also can not identify the gray zone, both and will form regular patterns of reaction in the visual is periodic corrugated. 

in the end, how to eliminate the LED display screen water ripple method is introduced: 
1, change the camera angle. The angle of the camera to shoot the object can cause the ripple, slightly changing the angle of the camera, through the rotation of the camera, you can eliminate or change the existence of any ripple. 
2, changing the camera position. In addition, through the left or right or up and down to change the angle of the relationship, you can reduce the ripple. 
3, change the focus. Too clear focus and high detail can cause ripples, slightly changing the focus to change the clarity, and thus help eliminate water waves. 
4, change the lens focal length. Can be used to change or eliminate water wave pattern with different lens or focal length. 

5, the use of mirror filter installed directly in front of the CCD and the exposure conditions satisfy the spatial frequency, thoroughly filtered images with high spatial frequency components, reduce the chance to display the ripples, but it will also simultaneously reduce the image sharpness.


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