How to deal with water ripples in LED electronic display?
The water ripple phenomenon in the LED electronic display screen has become an important obstacle to the high-definition display of the picture quality. So what is the reason for this phenomenon and how to deal with it?
1. The difference between water ripple and scan line phenomenon in LED display
(1) Water ripples: generally show an irregular arc-shaped diffusion state!
(2) Scan line: horizontal black stripe line, mainly due to the low refresh rate of the display screen, which is captured by the camera!
2. LED electronic display “water ripple” scientific name “moiré”
When shooting a scene with a digital camera, if there is a dense texture, inexplicable water wave-like stripes often appear. This is moiré. Simply put, moiré is a manifestation of the beat principle. Mathematically, when two equal-amplitude sine waves with close frequencies are superimposed, the amplitude of the resulting signal will vary according to the difference between the two frequencies.
3. The process of moiré pattern generation of LED electronic display
(1) The two stripes with slightly different spatial frequencies have the same position of the black line at the left end. Due to the different spacing, the stripes gradually to the right cannot overlap.
(2) The two stripes overlap, and the white line can be seen on the left because the black line overlaps. The right side is gradually dislocated, the white line is facing the black line, and the overlapping result becomes completely black. There are variations of white lines and all black, forming a moiré pattern.
4. The process of moiré phenomenon in LED electronic display
The pixel distribution density of the LED electronic display screen is just within the interval that the CCD can distinguish. It is inevitable that the digital camera will still interpret some of the identifiable results, but it will also add the gray-scale area that cannot be recognized. The sum of the two Regular lines will be formed, and the reaction is visually periodic ripples.
5. The method of eliminating moiré pattern of LED display
(1) Change the camera angle. Since the angle at which the camera is shooting objects can cause moiré, changing the angle of the camera slightly, by rotating the camera, can remove or alter any moiré that is present.
(2) Change the camera position. Additionally, moiré can be reduced by changing the angular relationship by moving side to side or up and down.
(3) Change the focus. Too sharp focus and high detail can cause moiré, and a slight change in focus can change the sharpness, which in turn helps eliminate moiré.
(4) Change the focal length of the lens. Different lens or focal length settings can be used to change or eliminate moiré.
(5) Install the filter in front of the mirror directly in front of the CCD, so that the exposure conditions meet the spatial frequency, thoroughly filter the high spatial frequency part of the image, and reduce the chance of moiré on the LED display, but this will also reduce the image quality. sharpness.