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Crosstalk with shutter glasses systems vs polarized systems
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Author:  Matthew [ Tue Aug 26, 2014 2:00 am ]
Post subject:  Crosstalk with shutter glasses systems vs polarized systems

A few weeks ago, I got an Asus VG278HE monitor and an nVidia 3D Vision 2 system. I was struck by how little ghosting it has with 3D. With previous 3D systems I've used, there is significant ghosting with high contrast scenes. With this system, there is only minimal ghosting, even with high contrast scenes.

It has far less crosstalk than any polarized 3D system I've seen, including my Zalman Trimon monitor and a couple polarized 3D theaters I've been to. The local theater where I live uses shutter glasses (XpanD glasses with a DLP projector) and also has only minimal crosstalk.

It's been years since I've been to a polarized 3D theater, though, and the Trimon monitor is from 2007. Are newer polarized 3D systems as good, or do shutter glasses systems generally have less crosstalk than polarized systems?

Author:  cybereality [ Tue Aug 26, 2014 11:16 pm ]
Post subject:  Re: Crosstalk with shutter glasses systems vs polarized syst

Both systems can (and do) have crosstalk to different degrees.

I find the cinema systems to be mostly high quality and without any noticeable crosstalk except in the worst cases. I've tried all different movie systems (linear polarized, circular polarized, shutter glasses, and infitec). I've also tried different home systems as well. I think they're are all acceptable quality, and have pros and cons. I guess my favorite right now is DLP projection, as I find the ghosting almost non-existent and the brightness is good. I also use an Nvidia 3D Vision 1 setup, which has some ghosting and a dark image but is otherwise not bad. I did use to use the Zalman Trimon and it was nice at the time but I would not go back to using it.

Author:  Matthew [ Fri Aug 29, 2014 1:50 am ]
Post subject:  Re: Crosstalk with shutter glasses systems vs polarized syst

cybereality wrote:
I also use an Nvidia 3D Vision 1 setup, which has some ghosting and a dark image but is otherwise not bad.


The Lightboost technology fixes both of these problems. :)



cybereality wrote:
I did use to use the Zalman Trimon and it was nice at the time but I would not go back to using it.


I think the Trimon monitor originally was better than nVidia 3D Vision, but not anymore.



When nVidia 3D Vision was originally released, and for a long time afterward, I was heavily critical of it, for two reasons:

1. The lack of support for OpenGL Quad Buffering (except on professional graphics cards), or any other open API

2. The issues with ghosting and overdrive artifacts on LCD monitors

nVidia has now fixed both of these problems.



One criticism I have long had of the Trimon monitor (and similar displays) is that even though they require glasses, the viewing angle restrictions are similar to that of autostereoscopic displays (although vertical instead of horizontal). I think the Trimon monitor should instead have been an autostereoscopic monitor (which used a liquid crystal parallax barrier, so the stereoscopic feature could be toggled on/off).

It also has struck me as not being a very well built monitor. They tended to have a lot of stuck pixels (stuck pixels are defective pixels with one or more subpixels that are always lit, not dark). When I bought my Trimon monitor, it had a stuck yellow pixel (this was really nasty -- it was very noticeable when that part of the screen was dark) and I had it returned. Even the replacement one Zalman gave me had a stuck green pixel (their policy allowed a maximum of one green dot). And when in resolutions other than the monitor's native resolution, it didn't allow you to turn off the monitor's built in scaling and didn't even have an option for auto-selecting the proper aspect ratio -- it only allowed you to select between scaling to 16:10 and scaling to 4:3, and would distort the picture if the aspect ratio was different from what you selected.

I also have been critical of shutter glasses not having as high a refresh rate as they should. Although 120 Hz is standard, since the glasses halve the refresh rate, that results in 60 Hz when viewed through the glasses, resulting in flicker similar to that of a 60 Hz CRT display. They also cause strobing artifacts when you move your eyes. (Try looking at a light through the glasses and moving your eyes rapidly to create a motion blur -- it will be dashed, with opposite dash patterns in the left and right eyes.) This also is reduced at higher refresh rates.

Shutter glasses probably are the best technology available for conventional displays, though. I notice that there are now some 4K TVs that have pixel row interleaved 3D, but I wonder if they have the ghosting and viewing angle issues that the Trimon monitors had.

Author:  bastian74 [ Mon Sep 15, 2014 11:25 am ]
Post subject:  Re: Crosstalk with shutter glasses systems vs polarized syst

Dolby 3D has the best format for passive 3D in my opinion. No special screens are required, no light loss from polarized filters either.
The main drawback is the requirement to calibrate colors, which could be automated.
http://en.wikipedia.org/wiki/Dichroic_filter

Author:  Matthew [ Tue Sep 16, 2014 8:49 pm ]
Post subject:  Re: Crosstalk with shutter glasses systems vs polarized syst

Although I have never seen 3D with it, I have long been critical of the Dolby 3D technology. It uses the wavelength to separate the left and right eye images, which I think would affect the color quality. And I wonder how much crosstalk it has (I think it would have a significant amount, because the wavelength of light would not be completely preserved when it reflects off the screen).

I also don't think it would have any advantage over shutter glasses systems.

The interference filter technology is not very popular for 3D -- Dolby is the only company I know of that uses it. I wonder why.



bastian74 wrote:
The main drawback is the requirement to calibrate colors, which could be automated.


Why do you need to calibrate the colors? What do you have to do to do that?

Author:  cybereality [ Tue Sep 16, 2014 10:11 pm ]
Post subject:  Re: Crosstalk with shutter glasses systems vs polarized syst

I tried the Infitech system (which I believe is the same as Dolby). I found it to be surprisingly good and didn't really notice any problems with ghosting or color reproduction. That said, getting a similar system at home is prohibitively expensive and not really practical. Even at-home polarized projection is a hassle and expensive. Especially considering the price and quality of DLP projection units.

I got a 720P DLP-3D projector for around $600 and it looks fantastic. Practically no ghosting, full resolution, bright image. It's great.

Author:  Matthew [ Wed Sep 17, 2014 4:18 am ]
Post subject:  Re: Crosstalk with shutter glasses systems vs polarized syst

cybereality wrote:
I got a 720P DLP-3D projector for around $600 and it looks fantastic. Practically no ghosting, full resolution, bright image. It's great.


DLP projectors actually don't have full resolution when used with shutter glasses systems, because they only display half of the pixels each refresh, using checkerboard interleaving. This means that if you view 3D with shutter glasses with them, you'll get half resolution.

The same is true of Dolby 3D, because it uses a DLP projector and displays the left and right eye images sequentially, using a single color wheel.

Shutter glasses are definitely better.



With LCDs, the Lightboost technology is a huge improvement. I had long thought that LCDs weren't well suited for use with shutter glasses, but with Lightboost, they're better than CRTs. The image is bright and vibrant, and crosstalk is minimal. There are some inversion artifacts, but it's not that bad. It actually doesn't reduce the resolution; the backlight just amplifies the screen's inversion pattern. I usually don't notice it.

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