There are still a few things I would like to say about LEDwalls and the Virtual Pixel (Geometrical Vs. Interpolated).

In the previous posts we learned that Geometrical is a relatively old technology and that it only works properly when LEDs are equally distant to eachother. The problem is that even in this case, there are some side effects.

The main side effects are related to the Minimum Viewing Distance, Chromatic Fidelity and Contrast Ratio. Why? you are probably asking. Good question. Lets see.

Minimum Viewing Distance

If LEDs are spread all over (and not grouped in units or pixels), what actually happen is that the pixel gets bigger. Right?

And if the pixel get bigger, the image must be looked at greater distance or it will appear pixelated (with dots). Right?

And if the image is pixelated, you must move away from the screen in order to perceive it as smooth and defined. Right?

What does that mean in terms of image quality? It means that the Minimun Viewing Distance increase. And you might want to consider that, expecially if you are installing the LEDwall indoor.

Chromatic Fidelity

The distance between the LEDs has another side effects: indeed, the closer the LEDs are to eachother, the better their single colors will mix, the sooner your eye will perceive the entire pixel color (the sum of the 3 basic colors: red + blue + green). Clear, no? Ok.

On the other side, the more distance you put between LEDs, the more distant you must be in order to perceive the right color mix. What does that mean? It means that not only the images at short distances might look pixelated, but they might also have a poorer chromatic fidelity (yellow might appear as a dot half red and half green)

Contrast Ratio

Last but not least, if you have LEDs spread on the LEDwall, the surface might not be as black as you would like it to be to ensure the best contrast ratio. Let me explain.

Each LED has a white background (or anyways clear) that is much lighter than the black surface of the screen. Now, if you spread this white LEDs on the black surface, what you get is a grey area.

Since the contrast level is a ratio between the light emitted by the LEDs and the environmental light reflected by the screen, you can very well understant that your surface should be as dark as possible.

Why Interpolated Pixel avoid all these problems?

Because it allows to put LEDs closer together, to form a clear unit (pixel). In this way you:   1) have a smaller minimum viewing distance because the pixel has a smaller surface;   2) get an higher chromatic fidelity because LEDs are closer and therefore colors mix faster;   3) you increase the contrast ratio because the more space there is between LEDs the more black the surface will look.

Each manufactuer will of course highlight the strong point of its technology, but bear in mind this information next time and make your own conclusion.

Ok, that's it. In the past few posts I tried to clarify a fairly complicated topic, that often create confusion among people approaching the LEDwall business.

Most of the time, the confusion is due to the fact that each manufacturer has its own approach and provide different solutions to the same problem, each one with its pros and cons.

I hope I provided you with useful information, that will help you to make a more conscious consideration when you have to decide which kind of LEDwall better suits your needs.

So how can you increase the image quality on your LED giant screen, without using the Geometrical / Squared Pixel (and its related side-effects)? Is there another way?

Dont panic! Yes, there is another way and it is called "Interpolated". How does it increase the quality by 400%? Well, I can tell you EXACTLY how it does it because I should reveal our Proprietary Algorithm for Image Elaboration... and I doubt they would like it here.

But what I can certainly do, is to give you an overview of how it work. To start, we can say that our Interpolated Technology is very similar to the MP3 technology used in the music industry.

MP3 is an audio-specific Compression Format Based On the Acoustic Perception of the Human Ear. It provides a representation of pulse-code modulation-encoded audio in much less space than straightforward methods, by using Psychoacoustic Models to discard components less audible to human hearing, and recording the remaining information in an efficient manner (similar principles are used by JPEG, a lossy image compression format). Please click here to learn more about MP3 Technology.

In the same way, the Euro Display Interpolated Pixel is a Compression Based On the Visual Perception of the Human Eye: by compressing a BIG image to fit the small resolution available on the screen, the Interpolated Pixel Proprietary Algorithm compress the images the way MP3 compress sounds.

This compression (together with the Image Persistence on the Retina) allows us to control the visual perception by showing details, in our case one pixel, where there is nothing: that's why it is called Virtual!

As you can see, with this state-of-the-art technology, it doesnt matter how far the pixels are, because the image quality does not rely on a geometrical distribution of the LEDs on the screen surface. Furthermore it also have other key advantages that Ill mention in the next post: I still have a few things to say about the two approaches to Virtual Pixel on LED Giant Screens, so please dont give up yet!

I admit these recent posts are more "technical" than usual... In the end, what should be important to you is the Image Quality of the LED screen! But Im sure these information will help you to make a more educated choice when needed.

So the Geometrical / Squared Virtual Pixel seems to be a pretty useful and "smart" technique. It uses half of two adiacent pixels to create other two.

It is pretty easy and straightforward once you understand the mechanism. So what are the limitations of this technique?

Well, there is only one main limitation, but it could be important. Let's see if I can explain it clearly:

In the previous post we saw how two adiacent pixels can create other two by "switching" the side LEDs of each pixel. In this case everything worked fine because the distance between the LEDs is the same distance we have between the pixels.



But let's say for example that I have a LED Giant Screen with a bigger pixel pitch, for higher viewing distances. What happen if the distance between LEDs and Pixels is not the same anymore? (see example below).



Well, in this case the Virtual Pixel you created is not identical to the Real Pixel anymore. The Virtual Pixels are more stretched then the Real ones and therefore the overlall image quality will be affected. In the image below, the Real Pixels are indicated by the Grey outline while the Virtual Pixels are highlighted in Blue. Can you see the difference?



Over the past 15 years Euro Display developed a technology that allows to go behond these limitations and guarantee a Superior Image Quality with ANY resolution.

Does it mean that the Geometrical / Squared Virtual Pixel is not a good technology? Well, let's just say that it is definetely not the most recent one! Some LED Giant Screen manufacturers still use it, so be careful: when considering your LEDwall supplier, make you check how their Virtual Pixel Technology works.

If you want to know how our "Interpolated Virtual Pixel Technology" works, dont miss the next post.

In the previous post I explained why LED Giant Screens use the Virtual Pixel: it's because it incredibly increase the image quality (+400%).

Now, how is that possible? Well, there are two different types of Virtual Pixel: the so called, "Geometrical or Squared" and the "Interpolated". Let's start from the first one.

Geometrical / Squared Virtual Pixel
This technology is based on a pretty simple geometrical concepts: if you have two identical shapes placed next to each other, by taking half of each shape, you can create other two identical shapes. Clear, isnt it? If not, the pictures below might help you.

Here we zoomed closer to the surface of a giant screen and now you can see 2 pixels, with 4 LEDs each (2 reds, 1 green and 1 blue), right? You see them? Ok.



Now, as I said, if you have two identical shapes placed next to each other, by taking half of each shape, you can create 2 more shapes. For example, if you have 2 identical pixels lying next to each other, by taking half of each pixel, you can create 2 more pixels... identical to the first two. Let's see it more clearly in the next image.

So, what happen when you combine the first 2 Real pixels, with the second 2 pixels that you created "Virtually"? You just doubled the number of pixels (from 2 to 4)! Now imagine to double the number of pixels you have in lenght, and - with the same technique -  double the number of pixels you have in height: well, you increased the number of pixles (and therefore the image quality) by 400%!

So this is how the "Geometrical / Squared Virtual Pixel". Pretty good, uh? Unfortunately Not. In the next post, I'll analyse the limitations and side-effects of this technology, in comparison with the "Interpolated Technology" we use on our LED Giant Screen. So you decide which one is the best ... stay tuned!