Ghosting/Crosstalk comes from Glasses - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 30 Old 07-05-2010, 08:08 AM - Thread Starter
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In fact I had the feeling it could be that, then I was able to test this with the 3D Vision system.

When the 3D Vision glasses are about to shut down, the left eye blink half a second ON, half a second OFF about 5-6 times. This is much longer than blinking 60 times a second.

In this half a second where the LCD are set to block the light, I was able to see bright parts of the screen and this could explain why we see ghosting/crosstalk with any current 3D TV/Monitors.

I believe the next big improvement will have to come from the glasses and this is somewhat great news, as all curent 3D TV/Monitors are actually doing a good job for delivering 3D. While a firmware can offer some very small improvment on this, I believe it's the glasses that need to be worked on. They will need to find a way to properly block the light more effectively. In the pasts years they were able to improve LCD TVs in a lot of way, Plasma also with better phosphor and such and now it's time someone focus on glasses. Something that should be easier to do than with any 3D TV set.

Now if I could find a trick on the 3D Vision set to manually control the glasses state, it would be easier to demonstrate.
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post #2 of 30 Old 07-05-2010, 03:23 PM
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Already covered in other threads.

This is how Samsung made their sets ghost less. They simply aligned the timing with the glasses shutters better.

The LCDs and plasmas still need faster refresh rates though since they do cause ghosting themselves (especially LCDs).
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post #3 of 30 Old 07-06-2010, 05:17 AM - Thread Starter
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Quote:
Originally Posted by peter0328 View Post

Already covered in other threads.

This is how Samsung made their sets ghost less. They simply aligned the timing with the glasses shutters better.

You mean they updated their firmware and completly solved the problem?? If it was that, many would solv the problem.. What I was saying is I believe the problem comes from the glasses, any current LCD glasses cannot block 100% of the light when in the block state. If we were able to put the glasses in a permanent block state you would be able to see thru them.

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The LCDs and plasmas still need faster refresh rates though since they do cause ghosting themselves (especially LCDs).

I thought some plasma had even faster refreshing rate than LCD...
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post #4 of 30 Old 07-06-2010, 06:40 AM
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Samsung has released several firmware to insure that the display and the glases are in sync.
The 3D Plasmas all have a maximum refresh rate of 120Hz and thryrely on the fact that the image phosphers decay to 0% brightness before the image for the other eye is displayed
All 3D TVs have a minimum240Hz refresh rate in order that they can insert a black frame between the actual image frames. There are some LCD's that have or will have a 480Hz refresh rate.
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post #5 of 30 Old 07-06-2010, 07:45 AM
 
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Quote:
Originally Posted by Rhialto View Post

I thought some plasma had even faster refreshing rate than LCD...

Not some - all. A PDP has a response time that is 2000 to 4000 times faster than an LCD; .001ms versus 4ms
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post #6 of 30 Old 07-06-2010, 09:08 AM
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On my VT20, I've noticed that ghosting is content-based rather than technologically-based. Some content is perfect, while others ghost fairly badly (such as some of the n3D programs).

I have yet to see ghosting in athletics coverage thankfully (world cup and NASCAR). Makes me excited for football and baseball.
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post #7 of 30 Old 07-06-2010, 09:16 AM - Thread Starter
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Quote:
Originally Posted by walford View Post

Samsung has released several firmware to insure that the display and the glases are in sync.
The 3D Plasmas all have a maximum refresh rate of 120Hz and thryrely on the fact that the image phosphers decay to 0% brightness before the image for the other eye is displayed
All 3D TVs have a minimum240Hz refresh rate in order that they can insert a black frame between the actual image frames. There are some LCD's that have or will have a 480Hz refresh rate.

Maybe but you understand when I say that if we were able to put the glasses in the block state permanently we would see thru them? Just like very dark sunglasses.
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post #8 of 30 Old 07-06-2010, 09:17 AM - Thread Starter
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Quote:
Originally Posted by Lee Stewart View Post

Not some - all. A PDP has a response time that is 2000 to 4000 times faster than an LCD; .001ms versus 4ms

That's what I thought... was replying to peter. Refresh rate is not the cause of ghosting/ct
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post #9 of 30 Old 07-06-2010, 11:01 AM
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Don't confuse the frame Refresh rate of the screen with the Response time to display a new frame when displayed. see:

http://www2.panasonic.com/consumer-e...00000000005702
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post #10 of 30 Old 07-06-2010, 12:33 PM - Thread Starter
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Quote:
Originally Posted by walford View Post

Don't confuse the frame Refresh rate of the screen with the Response time to display a new frame when displayed.

Again all what I'm trying to tell you is about the glasses. They are supposed to let the light pass thru/block the light 60 times a second in most case.

Now imagine the glasses permanently in the block state like if they were broken in that state, glasses will look black but if you wear them you'll find out you can see thru them.

Maybe my english is not strong enough to explain what I'm trying to... I can write all this in french if you prefer.
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post #11 of 30 Old 07-09-2010, 04:58 AM
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Quote:
Originally Posted by Rhialto View Post

Again all what I'm trying to tell you is about the glasses. They are supposed to let the light pass thru/block the light 60 times a second in most case.

Now imagine the glasses permanently in the block state like if they were broken in that state, glasses will look black but if you wear them you'll find out you can see thru them.

Maybe my english is not strong enough to explain what I'm trying to... I can write all this in french if you prefer.


Your English is very good; I wouldn't want to have to learn another language.

Thank you for your contributions.
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post #12 of 30 Old 07-09-2010, 08:30 AM
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The 3D TVs all refresh their screens 120 times a second so that each each eye sees 60fps. the glasses swith eyes at the same rate. With no power both lens are unblocked on the glases any you see normaly through them.
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post #13 of 30 Old 07-09-2010, 07:28 PM
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I am not going to esplain this again. Ghosting is not primarily content based but it is more visable on brighter scenes. The syncing can be screwed up but this have been fixed on most displays now. The primary cause on shutter glass systems is indeed the glasses and as these are improved ghosting will be lessened. You guys can research this in other threads where the reasons why are explained. You can believe whatever you want but 3D shutter glasses are the route of the problem. Not the displays once the syncing is fixed as it has been on some early model releases.
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post #14 of 30 Old 07-10-2010, 06:36 AM
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Quote:
Originally Posted by mark haflich View Post

I am not going to explain this again. Ghosting is not primarily content based but it is more visable on brighter scenes. The syncing can be screwed up but this have been fixed on most displays now. The primary cause on shutter glass systems is indeed the glasses and as these are improved ghosting will be lessened. You guys can research this in other threads where the reasons why are explained. You can believe whatever you want but 3D shutter glasses are the route of the problem. Not the displays once the syncing is fixed as it has been on some early model releases.

..

MarK, I know that you have explained this more than you care to but some of us thicker headed guys, me, didn't think that the glasses could be the cause. I am waiting for the new XpanD 103 glasses which may help to eliminate this problem according to them.

Thank you.
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post #15 of 30 Old 07-10-2010, 06:49 AM
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The reason ghosting is more prevelent with bright colored content such as the ocean in the MvA bridge scene is that if the glases lens are not 100% opaque for the inactive eye then some of the bright content sneaks through.
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post #16 of 30 Old 07-10-2010, 06:51 AM
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In simple terms, the glasses have tobe completely shut, they have to block the light entirely to say the left eye when the right eye image is on the screen. Now remembver all the bits about the image for each eye is not on the screen for 50% of the time. The glasses have to be synced with this and it really can`t be simultaneous because the image has to be fully written before the corresponding eye shutter can be opened and then it must close before the image isextinguished. The glasses must be fast and to eliminate cross talk, they must vlose completely. Also can`t have reflections yada yada.
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post #17 of 30 Old 07-10-2010, 08:06 AM
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Agreed but I don't know what make/models of glases meet both of these criteria.
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post #18 of 30 Old 07-10-2010, 10:55 AM
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Quote:
Originally Posted by walford View Post

Agreed but I don't know what make/models of glases meet both of these criteria.

RealD CrystalEyes is the best available at this time.

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post #19 of 30 Old 07-10-2010, 11:31 AM
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And the key is at this time. I may have not gotten this across, but the glasses because they are in essence an LCD crystal system working with a fixed polarizer, I think (not to be confused with polarizer glasses which are entirely something else and not under discussion, here) don`t completely close. Glass technology will improve but we can not now expect cheap glasses, even if say a company like Monster charges more for them, to do the job at a high level of performance. Things will get better and prices for the good stuff will drop. But this technology is not yet perfected for home theater and what is available in commercial theaters (mostly linear and circular polarizers) are price point solutions. Economics for the commercial theater owner. IMAX which uses linear polarizers is the worst they could give us. Circular polarizers which are more expensive would allow much more head movement without losing the 3D effect.

What you are buying now is early adopter. Understand that when you make any purchase. Things will get better and prices will drop.
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post #20 of 30 Old 01-08-2012, 04:00 PM
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Bumping to see if there's been any updates on universal glasses ability to block light.

Right now I get no ghosting on my set except when really bright things are put next to dark things and stereo effect is pushed heavily.

I like to have stereo at the highest setting in games, so it would be nice to know if there's a solution to this, or one in the works.

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post #21 of 30 Old 01-09-2012, 05:50 AM
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I have the monster vision glasses and with a DLP projector I don't see any ghosting. Although I do see ghosting using the same glasses with a JVC projector so it isn't the glasses in that case.
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post #22 of 30 Old 01-11-2012, 07:53 AM
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Originally Posted by Ronomy View Post

I have the monster vision glasses and with a DLP projector I don't see any ghosting. Although I do see ghosting using the same glasses with a JVC projector so it isn't the glasses in that case.

If it is the ability to block light, it may be that one projector is brighter than the other and thus light gets through in the dark shutter blocked state.

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post #23 of 30 Old 01-11-2012, 08:10 AM
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The conventional thinking these days on AVS Forum is that it's the response time of the panels in the projector that really causes the problem. Because of the way DLP tech works, it's able to respond very quickly, even when going from full dark to full brightness (and the opposite) for any given pixel. So it can transition almost instantly when the left and right images are alternating. But it would seem that current LCOS tech (like in JVC projectors), can't quite keep up during certain types of high contrast scenes.
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post #24 of 30 Old 01-11-2012, 10:28 AM
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Video cross talk can be caused by the TV display(except DLP models) or by the slow response time of the glasses or in some cases by the source content.
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post #25 of 30 Old 01-16-2012, 09:02 AM
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Quote:
Originally Posted by chaosemerald View Post

If it is the ability to block light, it may be that one projector is brighter than the other and thus light gets through in the dark shutter blocked state.

Light penetration should be a linear phenomina, IIRC. That means that the lens will block some percentage (say 99%) of light. On a brighter display, the ghosts will be brighter, but so is the display, and your eyes will adjust to that, so the ghosting should look the same on otherwise equivalent displays that differ only in brightness.

As an aside, it is often recommended to play with the screen brightness to reduce crosstalk. This is probably useless advice from people who are just imagining an improvement, but might work in some cases. The only way for tuning brightness to make a difference is if there is some aspect of the display technology that changes the timing (an amplitude-dependent pixel response time, for example) or the brightness changes the gamma curve in a way that is less easily processed cognitively. Most backlit displays adjust brightness merely by tuning the backlight, so in those cases, it will do nothing.
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post #26 of 30 Old 01-16-2012, 09:19 AM
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Holy old thread! So. Any better glasses out there?
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post #27 of 30 Old 01-16-2012, 10:02 AM
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Quote:
Originally Posted by chaosemerald View Post

If it is the ability to block light, it may be that one projector is brighter than the other and thus light gets through in the dark shutter blocked state.

Yeah the brighter projector (DLP) has no ghosting that I notice! I bet there is some there if I were to test it with test screens but I can't see it in use.

Using the Bit Cauldron RF glasses. 100% duty cycle in the glasses looks perfect on the DLP. Even a low 60% duty cycle on the glasses with the JVC I have ghosting. Its the LCOS panels that are too slow to change enough to eliminate it.

I can understand that glasses don't completely block the other eye in some designs but the Monster Vision glasses are quite good so after what I have witnessed its not all glasses causing this.

DLP is fabulous for 3D viewing but I prefer the JVC for 2D viewing. better blacks.
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post #28 of 30 Old 01-16-2012, 11:28 AM
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Originally Posted by Ronomy View Post

Yeah the brighter projector (DLP) has no ghosting that I notice! I bet there is some there if I were to test it with test screens but I can't see it in use.

Using the Bit Cauldron RF glasses. 100% duty cycle in the glasses looks perfect on the DLP. Even a low 60% duty cycle on the glasses with the JVC I have ghosting. Its the LCOS panels that are too slow to change enough to eliminate it.

I can understand that glasses don't completely block the other eye in some designs but the Monster Vision glasses are quite good so after what I have witnessed its not all glasses causing this.

DLP is fabulous for 3D viewing but I prefer the JVC for 2D viewing. better blacks.

The black level is not a function of whether it is DLP or Lcos but the fact the Higher lumens output of the 3D pj will suffer in black level. A comparable lower lumen 2D DLP pj can have very good black level as well.
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post #29 of 30 Old 01-16-2012, 01:30 PM
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Quote:
Originally Posted by mkoss View Post

The black level is not a function of whether it is DLP or Lcos but the fact the Higher lumens output of the 3D pj will suffer in black level. A comparable lower lumen 2D DLP pj can have very good black level as well.

Big difference is native contrast ratio between the two. The JVC in my long throw setup is giving me over 15k:1 real measured contrast ratio where the Acer is around 3.8k:1(spec).

I can bring the light output down with ND filters to match them pretty closely in peak output but the Acer never comes close to the JVC with overall black. Don't get me wrong it is still very watchable. I like the Acer and it doesn't cost a lot of money.

Depth in dark scenes is much better on the JVC watching 2D movies. The Acer lacks only on the very dark scenes with not much light in the image and while watching 3D which is dim. 84% loss in light with the glasses on and shutters active. Use an ND8 filter on a 2D image and its basically the same loss in light compared to a 3D image with glasses on. Do the math. ND8 is a drop of 87.5%. Measurements of 3D glasses online are measuring about 84% loss.

I have measured my JVC in the past but never ran an actual measurement on the Acer. I just got the new i1 D3 pro meter for use with Chromapure so will have to give it a measure.

Also what I like on the Acer is the Degamma which can flush out shadow detail on dark fims in 3D like the latest PotC movie. It looked quite good except for when a bright scene came it really didn't get brighter because I was using the gamma setting that boosted the range in dark scenes so higher peaks were flat looking. Dynamic IRIS whould have been nice to have in that movie.

Other than that the little DLP rocks! Great for gaming too.

You are correct that when there is sufficient brightness in the image where 30% of the display is bright...the blacks look pretty good. Like in 3D Hubble which is in space but the image of the hubble is very bright because of the bright sun. Thats because our pupils close up due to the bright part of the image. 4k:1 isn't that bad in most scenes plus 3D needs strong peak light output and the JVC doesn't come close to the light output from the Acer on a 120 inch screen. When I got the Acer I measure up around 40ft-L off the screen in best mode and 90+ in bright mode. My JVC is about 14ft-L with a few hundred hours on the bulb. Just doesn't cut it in 3D.

Ron
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post #30 of 30 Old 01-16-2012, 02:28 PM
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DLP has the best 3D I've ever seem. And almost best bang for buck. (not anymore IMO)

To bad I can't sand SSE and see no point in having a huge picture if it looks like crap.
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