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This topic comprises 2 pages: 1 2
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Topic: Is digital IMAX 2K – or a bit more?
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Antti Nayha
Master Film Handler
Posts: 268
From: Helsinki, Finland
Registered: Oct 2008
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posted 01-30-2012 08:41 AM
(Edit: sorry, wrong forum. Admins, please feel free to move this to Digital Cinema.)
There’s some conflicting information going around about the resolution of dual-projector digital IMAX, aka. LieMAX. Let’s clear this up once and for all, shall we?
As we all know, the fact is that they’re currently using two 2K projectors with overlapping images. But already back in 2009 or 2010, I read somewhere that the two projectors are actually not aligned at exactly the same position, but the pixel grids have a difference of exactly half a pixel (can’t find the source now, of course).
So with a setup like that and a 4K source, you could theoretically extract two slightly different 2K images for each projector and achieve a resolution higher than 2K. Think of it as a modern version of interlaced video. Although I still can’t imagine how the alignment could ever be made perfect enough for this to actually work.
Now, I noticed that at least M:I4 was distributed to digital IMAX venues as a 4K DCP, which would only make sense if the above is true.
Then again, some people are claiming that the two projectors are aligned at exactly the same point, pixel by pixel, both projecting the exact same 2K image. I think someone who works at an IMAX theatre even said this on this forum a while ago…?
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Antti Nayha
Master Film Handler
Posts: 268
From: Helsinki, Finland
Registered: Oct 2008
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posted 02-01-2012 06:47 PM
quote: Carsten Kurz
What tells you that they get special IMAX 4k DCPs?
Well, I saw one. ![[Smile]](smile.gif) Of course, they could simply be future-proofing their stuff for an upcoming 4K system.
quote: Carsten Kurz
Anyway - MI4 is available in IMAX DMR on film, so why bother about 2*2k...
No real reason at all, just curious. As I said, there are all kinds of rumors floating around.
It’s been announced that IMAX and Kodak are going to roll out their laser system already in 2013 (no word yet about the resolution, but 4K would seem most likely indeed). Barco, on the other hand, estimates that it will take another 3–5 years before their offering is ready to market. Naturally, they claim that it’s technically superior.
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Marcel Birgelen
Film God
Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012
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posted 02-28-2012 12:10 PM
Sorry for bumping this topic, but I landed here because I had exactly the same question as the topic starter, after Googling a bit around, I got some conflicting information.
I recently watched the first two movies in a local digital IMAX (aka LieMAX): MI4 (2D) and Journey 2 (Stereo-3D). REAL 15/70 IMAX has almost become extinct around here, the only real IMAX theatres left witin about a 4 hours drive only show the standard documentaries they've been showing for ages.
I've noticed that all the preshow content was projected trough a single projector, the second projector only kicks in right before the first "look-how-fabulous-we-are" IMAX trailer.
First I thought they might be slicing up the image vertically or horizontally, but after looking back to the projector booth, I could clearly see two full images being reflected on the glass in front. Also, getting that right without a visible seam might be even harder than projecting two images on top of each other.
During the MI4 presentation, the auditorium was almost empty, so I took the opportunity to walk to the screen. The Screen-door effect is clearly visible close upfront and you can clearly see pixels in a grid that looks rectangular to me.
So it looks like they manage to project two images exactly over each other. I cannot say if they project EXACTLY the same image from both projectors, but at least it alligns perfectly on the screen as a single pixel grid.
I still don't know how they achieve this, or more specifically, how they maintain this level of calibration.
There is a camera mounted near the booth pointed at the screen, that looks like an ordinary security camera, it is not even pointed straight at the screen, but with an angle. I guess you could use that to match both pictures using some predetermined test patterns, but I highly doubt you could detect alignment mismatches during a running show, let alone correct them on the fly, without a decent test pattern on-screen.
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