So Are You Now Ready to Buy An LED Wall?

As enticing as it might seem at the prospect of buying direct, avoid "buyer's remorse" by working with someone you trust in finding the right LED wall for your needs.

So Are You Now Ready to Buy An LED Wall?
With some LED walls, there can be the problem of what is called the moiré effect, as is distinctly shown on the LED wall screen to the right. The creation of moiré is by the parallel lines in both the camera’s imaging sensor and the on the LED wall.
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It sure is exciting to think that you are about to embark on a journey that so far very few have done. 

Sure, you see the flashy advertisements and a few cornerstone quality projects in the trade magazines, but how do you go about buying a LED wall?

There are ways of minimizing the effect of moiré and lines when using a camera on an LED wall.


First off, I want to dig into a few more details that were touched on in the last article I wrote on August 2, and then talk a little about the major pitfalls to avoid.

So let’s discover what the term moiré means, and how it is caused … along with horizontal lines.

The best way to “see” what it is, can be accomplished by watching this YouTube video

The creation of moiré is by the parallel lines in both the camera’s imaging sensor and the on the LED wall.  All of the LEDs are lined up in rows and columns which make lines that are set up similar to a 3-chip camera.  Now we are not going to dive too deep in to the camera side of things, but the single chip vs. 3-chip camera will make a difference here, in how the LED wall looks on screen.  Just like the modern LED wall has three colors per pixel, the 3-chip camera has one pixel per color at each location, where the single chip has typically groups of four sensors, two being green, one red and one blue.  They are not overlapped, and there is interpolation going on in the in-between spaces on the image sensor.  (The reason there are two green is the human eye is most sensitive to green light and the Bayer pattern on a single-chip camera is trying to reproduce that, like the eye does.)

Now, if you try taking a still image of the LED wall and you see horizontal lines where there is black or dark lines, that has more to do with the refresh rate of the LED wall and the camera shutter speed, as shown in the photo with this article. If you have a fast shutter speed and slow LED refresh rate – this issue shows up very distinctly – but it can be minimized or eliminated by both the quality level of LED wall and also the camera shutter speed.

So this all seems so technical and confusing, right? 

Well maybe, but there are ways of minimizing the effect of moiré and lines when using a camera on an LED wall.


More About Stefan Svard
Stefan Svard has been involved with the A/V world for virtually all of his life. His first experience dates back to when he was 13 years old, and fast forward to the present. He now has the opportunity to serve a much larger base of people through his company, Audio Video Electronics, a Minneapolis-based AVL systems integrator, which specializes in sound systems, acoustic design, sound transmission isolation, video systems and lighting systems.
Get in Touch: ssvard@audiovideoelectronics.com    More by Stefan Svard

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Worship Facilities Magazine, November-December 2017
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Article Topics

Technology · Video · Video Displays · Projection · Team Management · Budgeting · Audio Video Electronics · Brightness · Image Sensor · Interpolation · LED Walls · LEDs · All Topics

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