3D PROJECTION TECHNIQUES

3D PROJECTION TECHNIQUES

How to project 3D?
There are several methods and systems of 3D projection. But before we begin, it is recommended to learn two important facts:

3D projectors may not work in 3D
– confusing? Definitely! The reason for this lies in the simple fact that there is now a clear definition for three-dimension, and there are a number of methods, formats and technologies which contain different features and settings. Therefore, if you purchase a random three-dimensional projector, it is quite possible that it will support only one three-dimensional format (e.g. Pageflip) while you are interested in a more three-dimensional standard projector, which is available online (e.g. Side By Side). So it is recommended not to purchase a 3D projector before reading till the very end.

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Acer’s 3D Projector

3D projection “Red – Blue” is irrelevant- Why?

This is because the quality of this 3D screening technology, called anaglyph, is only average, on a good day. And for those who have no knowledge about 3D projection technologies, here it is, summarized: 3D red/blue projection is low quality, old and irrelevant, while other projection methods (Polarized, Active, Infitc etc.) offer much better results. Think for a minute, you will never get 3D glasses in red or blue (actually cyan, and not blue) at the entrance to a cinema or when buying a 3D TV / projector. Why? It is because it will just be an insult to 3D technology! So why are people still using this technology? As it’s cheap, simple and does not require any complex knowledge. Each projector and screen can play in “three-dimensional” red/cyan – you only need a 3D movie Red/Cyan, a pair of anaglyph 3D glasses, and you can relax and enjoy. Oh well, maybe not really enjoy! If someone wants to take 3D projection more seriously, he is welcome to read the explanations presented below.

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3D Glasses Red – Blue / Cyan

How do you choose a quality 3D system for 3D screening?

As we said, there are several methods for screening in 3D. And to select the preferred method we should first clarify a number of points. First thing we want to define is what we want to see in 3D, or in other words, its purpose , is it for watching 3D movies, playing 3D games, watching 3D online or more? The second thing we need to define is the amount of viewers, a small amount of viewers (family screening) or a large gathering (event screening). And finally, as with anything else in life, we should carefully consider our budget.
Having defined the above points will help us move forward and select the 3D projection system suited to our needs. Here we will discuss two key techniques and best practices: the active 3D projection method and the passive 3D projection method (polarized).

System 1: Polarized 3D projection – Dual projector

Polarized 3D projection systems (passive 3D projection), is the preferred screening system in 3D when it comes to a large number of viewers, and that is because the 3D glasses are significantly cheaper. So if you plan to perform a screening event or just invite all your family and friends, then this is the system you should consider. Beyond the price, the 3D dual projection system is more complex and requires more knowledge for the installation and adjustments. Furthermore, it requires a special projection 3D silver screen which is used to keep the light polarized, thus, maintaining the 3D effect. The dual project 3D system is ideal for watching 3D movies, but if we want to use it for more advanced applications, we will need more knowledge.
Polarized 3D projection systems are used in 3D cinemas such as RealD, IMAX, DepthQ, MasterImage etc. Though in 3D cinemas the polarized 3D projection system is based on a more expensive single projector technique (and not a dual projector) the technology itself is similar and the 3D quality can be almost identical.

What is needed to build a polarized 3D projection system?

  • A pair of identical and ordinary DLP or LCD projectors – projectors does not need to be 3D in the dual projector method.
  • A pair of 3D filters (3D polarizers) compatible with the type of projector.
  • Polarized 3D glasses compatible with the 3D filters.
  • 3D silver screen or 3D silver paint (to maintain light polarization)
  • HDMI cables. If you are using Frame Pack format you should use HDMI 1.4 or higher.
  • 3D content – can be a 3D movie, 3D Blu-ray disc, 3D Games, online 3D channels or any other format of 3D.
  • Content player. The player can be a computer, Blu – Ray, PlayStation, streamer or other. Note: This system requires designated computer software or an external demuxer.

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Polarized 3D projection system (passive) – Dual projector

System 2: Active 3D projection – uses one projector

The active 3D projection system is preferred for screening in 3D when it comes to a handful of spectators, it costs less for a small crowd (around 10 viewers or less), it is relatively simple in terms of components and integration and it supports all the different 3D applications we mentioned earlier. Its main disadvantages are that the glasses are significantly more expensive than the 3D polarized glasses and can cost around 100-150 USD per unit. Another disadvantage is that the glasses are in constant communication with the screen using the emitter, so it can sometimes cause flickering and mild dizziness. Active 3D projection technology is implemented in Xpand 3D cinemas.

What is needed to assemble such a 3D projection system?

  • A 3D Projector, 120 Hz, which recognizes how to get at least one 3D format (usually Pageflip). Note: You can also purchase a 3D projector which can already play a 3D format directly from a disc on-key (example SBS), then there is no need for a converter for the player and 3D projector.
  • A 3D converter which knows how to convert a standard type of 3D format into the specific type which is supported by your 3D projector- the most standard type of 3D format which can be found on the internet is the SBS 3D format.
  • Active 3D glasses. If you are using an IR/BT/RF emitter then you will need compatible 3D glasses, if you use a 3D converter for 3D DLP projectors you will need 3D DLP-Link glasses, in any case it is recommended to use a branded type of 3D glasses.
  • HDMI cables. If you are using Frame Pack format you should use HDMI 1.4 or higher.
  • 3D content. Can be a 3D movie, 3D Blu-ray disc, 3D Games, online 3D channels or any other 3D format.
  • Content player. The player can be a computer, Blu – Ray, Playstation, streamer, or other.

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3D glasses for active three-dimensional projection system