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Josh

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Posted on Saturday, June 22, 2002 - 2:17 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Hi all,

I first tried shutter glasses in the mid-'90s, at a friend's house. Back then I was a bit disappointed by the ghosting. So I never ended up buying any. I figured maybe they'd refine the glasses and fix the problem over time (with higher refresh rates, maybe?)

Well recently I was given a set of relatively new H3D glasses by i-O Display Systems - the ones specifically intended to go with NVIDIA cards (I have a GeForce3). Setup was pretty painless. Gaming with the glasses is fun, but unfortunately, I still see a considerable amount of ghost images (crosstalk between left-right).

So here's my question(s): Am I doing something wrong, or is that *just the way it is*? Are my expectations (for no ghosting) too high? Is it a persistence issue, which could be helped by a lower persistence monitor? (Not that I want to give up my Trinitron!)

Answers and thoughts appreciated. Thanks!

Josh
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M.H.

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Posted on Sunday, June 23, 2002 - 9:33 am:   Edit PostDelete PostView Post/Check IPPrint Post

There is no solution ofr ghosting on monitor - the phospors on the screen are simply to slow ...
There is only one "NO GOSTING" solution - DLP projector optimized for stereoscopy (Christe Digital Mirage 2000, price 40 000$).
A bit expensive but the result is realy fantastic :-)
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Anonymous

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Posted on Sunday, June 23, 2002 - 11:15 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Lets point out that Barco also can play the same game as Christie with same quality and price.
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Anonymous

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Posted on Sunday, June 23, 2002 - 11:16 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Dont forget the glasses that dont turn 100% black and the minimal sync misalignments that the eyes might register.
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Marvio

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Posted on Monday, June 24, 2002 - 5:42 pm:   Edit PostDelete PostView Post/Check IPPrint Post

JOSH,
To summarize...
Yes, unfortunately, it just the way it is, though higher refersh rates and the "new" ajustments on the det. drivers greatly reduce ghosting it is still a problem.
Have you tried the point of convergence ajustment? You can do it by holing ctrl and tapping either f6 or f5, while in game, that helps a lot....
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Josh

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Posted on Thursday, July 04, 2002 - 5:54 am:   Edit PostDelete PostView Post/Check IPPrint Post

I'll try that Marvio. Thanx for the help, to all you guys!
Josh
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Scotty

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Posted on Monday, August 05, 2002 - 6:17 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Er, I thought higher refresh rate made the problem worse (slow phosphor response) ??
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Tommi Korhone

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Posted on Wednesday, October 22, 2003 - 11:35 pm:   Edit PostDelete PostView Post/Check IPPrint Post

I don't believe it is the refresh rate at all.
I have eDimensional glasses, GF4 4800 and a regular Samsung SyncMaster 900 monitor. The ghosting is ever -existing and very much the same with _all_ the refresh rates from 60 to 150Hz.

I believe it is the LCD shutter element long step-up and step-down times. What I searched for commercial elements, the times seem to be in orders of several ms for 90% response... together being as long as 20ms. To my understanding this can only be compesated with changing the pre-close time. Even if the eDimensional glasses may have very good quality LCD element, it still must be some milliseconds, and that makes the ghosting hard to avoid. Unless there is changeable timing formula for shutter pre-time change.

Current monitors do have decent phosphore life, and looks like the shutter response time is longer.
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DOKWORM

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Posted on Saturday, November 01, 2003 - 5:47 am:   Edit PostDelete PostView Post/Check IPPrint Post

Or you could do what I did, make some 'glasses' out of stepper motors and a piece of card on each, the card rotates over each eye in sequence, no ghosting on a low persistence screen, but heavy noisy glasses :)
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TKorho

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Posted on Saturday, January 10, 2004 - 12:21 am:   Edit PostDelete PostView Post/Check IPPrint Post

Then again Dokworm, you might want to spill out some more information, if you will? I mean: yes I have the glasses, monitor, all the driver setups and all. And I do get annoying ghosting. :(

I am willing to spend some EURO for a fix. :-J
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David C. Qualman

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Posted on Sunday, January 11, 2004 - 6:19 pm:   Edit PostDelete PostView Post/Check IPPrint Post

Ghosting caused by the persistence of the phosphor in the monitor is affected by the refresh rate. If the monitor has a very high refresh rate, the phosphor is still glowing with the prior image when the next field is displayed. Lower refresh rates give the phosphor more time to decay, providing less of the prior image as ghost.

Ghosting is also caused by the switch-off time of the LCD shutters, as well as their contrast ratio. The contrast ratio gives a lower limit to the ghost elimination. With a 300:1 contrast ratio, we will always get 1/300th of the light leaking through - guaranteed ghosting. None of the LCD's have infinite:1, like the pieces of card that DOKWORM uses.

The switch-on (go to full dark) of most LCD's is on the order of microseconds. But the switch-off (switch to clear) time is basically about 2 milliseconds (it is a non-linear curve, and in about 2 milliseconds is effectively clear). Ideally, this would be in the vertical blanking period. If the pre-close time is adjusted, you get extreme ghosting at the top or bottom of the image. Because, the glasses will be switching in a region where the image is currently being drawn.

The best solution, but least likely, is to have the scenes constructed to minimize ghosting. Reduce the regions of contrast, so that any crosstalk that occurs is not noticed.

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