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Understanding Moire Pattern


moire pattern example


What is the Moire Pattern?

Moire Pattern is a visual phenomenon that involves repetitive details such as lines, dots and colours in an image. At times, it can be used deliberately to produce a special effect but most of the time, it occurs as a fault. This can affect the quality of the image captured.

 


led walls and moire pattern

Why LED Walls?

In LED walls, each LED is one pixel of an image. The distance between the center of one LED to the next is called pitch. The closer the LEDs are to each other, the closer you can be to the screen and see a good image.

These patterns ruin the image quality. It’s one of the biggest challenges that photographers face. Soft images with less details have less chances of Moire fringes. The sharper the image, the higher the chance of Moire.

 

How is Moire Pattern formed?

Moire Pattern is formed by the overlap of two patterns against each other. In simpler words, when an opaque pattern overlaps with another pattern, the Moire effect is produced. This occurs when the pattern captured is exceeding the resolution of the camera. For this reason, cameras with higher resolution would reduce the chances of Moire fringes being formed.

The similar pattern in both the object and the imaging chip results in a third pattern called Moire. Anti aliasing filters are used to reduce this effect but this results in a softer image. Sharper images have more chances of Moire. This is why, the cameras that are designed to produce sharp images, result in Moire fringes more often than not.

Reducing the detail in capturing images has helped the photographers. But now, there are high resolution cameras that can eliminate Moire Patterns. With low resolution cameras however, it’s difficult to avoid Moire.

 

How does the Moire Pattern effect LED display?

When Moire is noticeable, it often results in an unpleasant viewing experience. The original beauty of the visuals is ruined. This effect often occurs when a jacket or a certain clothing with weaving patterns is being captured. If the patterns are denser than the resolution of the sensor, it results in a LED Display Moire pattern.

Due to this, anchors and broadcasters often wear clothes that would not result in the Moire. It’s even more noticeable when such objects are being moved. The image result in such cases is not good. Especially in professional scenarios, the Moire effect risks the reputation of the broadcasters and photographers.

Even if it is eliminated by softening the image, the overall image quality is not the best with such editing. Softening the image can eliminate some of the details of the image. There are other ways that help in eliminating the Moire during and after production.

 

Combating Moire Pattern while capturing

It’s very difficult to eliminate the Moire after production. Though it is possible, the best way to eliminate LED Display Moire patterns from forming on LED is to avoid it when shooting. Most of the causes of Moire actually occur during production, so solving it when capturing it reduces the risk of Moire largely.

Some of the ways to reduce Moire during production are,

  • Change the camera angle

Moire is caused by the overlap of two contrasting patterns. When Moire is forming at a certain angle, it means that the angle is causing the patterns to overlap. The best way to fix this issue is by changing or adjusting the angle of the camera. Most of the more issues will be fixed by this adjustment.

  • Adjust the focal length of camera

Most of the Moire can be simply solved by adjusting the focal length of the camera. When you change the focal length, it adjusts the resolution of the image. This reduces the chance of Moire patterns forming by a great number. Another alternative to this is, changing the distance.

Move a bit closer or farther and try to find the perfect distance. Once you have moved to the perfect distance, Moire will eventually disappear. Just keep in mind you would need to move around a bit, to find the best distance.

  • Change the focus to a different area

If the Moire patterns are forming, that means two patterns are overlapping. This can be solved by changing the focus. Change the focus from where the patterns are, this will eliminate the overlap and eventually remove the Moire effect. If it’s necessary to focus at the site of patterns, just adjust it around a bit and focus on an area around the patterns.

  • Adjust the shutter speed

If you adjust the shutter speed, and lower it a bit, it will help you make up for the low refresh rate of the LED Display. This will help you in lowering the horizontal bar from the display.

  • Anti-Aliasing Filter

If other methods don’t work, go for Anti-Aliasing Filter. With this filter, the repetitive patterns will be blurred softly, which will reduce or eliminate the Moire Filter produced by the overlapping of similar patterns. However, you need to keep in mind that this may reduce the overall quality of your image.

 

Reducing Moire on LED

There are instances when Moire is not caused during production but is caused by the LED Display. Due to Moire the viewing experience is ruined as a result of bad image quality. There are many technologies these days that reduce the problem of Moire effect forming on the screen. Some of such technologies are,

  • Optical Processing

With Optically processed large LED screens, the more interference can be largely eliminated. Many manufacturers around the world have great expertise in this technology. In this technology, optical processing curtains are fixed near the light eliminated tube of LED. The screens with this technology only use specific light absorbing materials and lenses to work well with TV cameras.

This technology also prevents the image from distorting regardless of how close the lens is. The moire effect can be eliminated well with this technology.

  • Ultra fine LED modules

These days, some companies offer ultra fine COB display modules. Since these modules have a smaller pitch, the distance of the moire effect is reduced. Due to this, the shooting distance is not a problem. This can reduce the LED Display moire patterns.

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