3D Vision Blog

A normal user's look into the world of 3D Stereo Technologies

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Reducing The Ghosting On Acer GD245HQ / GD235HZ 120Hz Monitors

June 6th, 2010 · 63 Comments · GeForce 3D Vision

The crosstalk or ghosting of images (leaking of part of the image for the left eye into the right eye and vice versa) is a common problem with the current generation of 3D-capable 120Hz LCD monitors with different factors influencing it. One of the common issues is that the LCD panels are still not fast enough in terms of response time and because of that the monitor manufacturers resort to the so called Overdrive function (using more voltage to drive the pixel change state faster) in order to increase the pixel response rate. This works to some extent, but may as well lead to other issues like burnt colors resulting in colored ghosting visible in stereo 3D mode for example. Another common cause for ghosting is having brighter colors on darker backgrounds or vice versa, especially if the separation between the left and the right eye is higher. And then again there is the so called top and bottom ghosting that represents more ghosting on the top and at the bottom of the screen that is usually caused by not so good timing with the image on the screen and the shutter glasses. And since I’ve been trying different methods of reducing ghosting lately, here comes another effective solution that can help you reduce the ghosting when playing in stereo 3D mode with an Acer GD245HQ or Acer GD235HZ 120Hz LCD monitors. The solution is based on custom modifying the color temperature levels of the monitor from the Service Menu that is usually not available to the normal user, but you can call it if you know how to do it. The good news is that the same method might also work with the ViewSonic VX2268WM (I’m already working on that, so stay tuned), but will unfortunately not help the owners of the Samsung 2233RZ as the Service Menu of that model is not so good in terms of additional controls available.

Lets get back on the Acer. For the following examples I’ll be using a short demo video shot by the user 3D Frank shared over at Nvidia’s 3D Vision forums that is a great example for ghosting, you can find a download link at the bottom of the post if you wish to try it on your monitor. Have in mind that the following ghost reduction method works not only when watching stereo 3D videos, but also with 3D photos and when playing games in stereo 3D.

And here is how you can call the Service Menu on the Acer GD245HQ / GD235HZ:

– Turn off the monitor
– Press and hold the first menu key (the leftmost one)
– Press the power button while still holding the 1st menu key
– When you see the image on the screen you can release the menu key
– Press the third menu key (the middle one) to call up the Service Menu
– Navigate in the service menu just like in the normal one, but now all options are changeable
– To return back to the normal mode just turn off the monitor and turn it back on the normal way

Lets me start with how the display looks by default when showing a stereo 3D image and you are not looking through the shutter glasses. The blue menu in the top left corner is the service menu that is showing the default options for the display, as you can see the Overdrive (OD) function is active and on the screen you can practically see doubled images of the boats and burnt out colors of the most bright white on the sailboats.

When you put on the glasses instead of doubled sailboats you’ll start seeing ghosting which looks like shadows as you can see on the picture above taken through the right lens of the shutter glasses. Again here we still have the Overdrive function of the display active.

Now lets see how the things look when the Overdrive function is disabled. Without the shutter glasses on the image still looks doubled, but there are no burnt colors. Other than that no significant difference can be noticed with the named eye…

Overdrive is still disabled, but now looking through the glasses you can see significant difference in the image as compared to looking through the shutter glasses with the Overdrive function enabled. Instead of just some shadows the ghosting here is so severe that you still see doubled objects, although a bit more faint than when looking without the glasses. This is just to give you an idea of what can happen when the response time of the pixels is not good enough and why monitor manufacturers are using Overdrive on the LCD panels.

Now comes the fun part. I’ve decided to use the Cool temperature preset available in the Service Menu to modify in order to reduce the ghosting. So the new settings that I’ve defined for it are 100 for Red, 90 for Green and 85 for Blue. Although I’m using the Cool preset my settings are warmer because the Red color is higher (you can decrease it to about 85-90 to get cooler temperature), but I prefer the Warm color temperature and this makes it easier to compare it with the default Warm preset.

After doing the tweaking of the Cool preset from the Service Menu of the monitor you need to turn off the monitor and then turn it back on normally to get to the normal monitor menu, where you need to select the Cool preset in the Colour Temp settings in order for the things to work and you to have less ghosting. You can cycle between the Cool and Warm color presets to see the difference, the Warm preset should have easily noticeable color ghosting while the custom Cool preset should have hardly any visible ghosting.

And so how does the tweaked settings look like in terms of ghosting, you can see in the picture above taken through the right lens of the shutter glasses. There is hardly any visible ghosting left, although if you look up close and carefully you may still notice some very faint traces, but that should not bother you when using the monitor normally as it is hardly visible anymore.

Before and after this tweak you can try a game like Tomb Raider: Underworld with a separation of lest say 50%-100% (depending on how much you can handle) in order to have high separation and to compare the ghosting. You will however see that there is still some top monitor ghosting, it seems unaffected as it is probably caused by synchronization timing issue whit the shutter glasses and that is why the above tweak does not affect it. Still the end result where you don’t have burnt colors, color ghosting and almost no ghosting at all is completely worth it if you ask me, so if you own an Acer GD245HQ or Acer GD235HZ monitor I recommend you try my tweak and report your results in the comments below.

And just one more thing I’ve noticed about the Acer while playing with the “ghostbusing” settings in the Service Menu of the monitor. When you turn on the monitor and immediately display a stereo 3D image you’ll most likely see more ghosting, but after 2-3 minutes the visible ghosting gets reduced a bit. This means that it probably takes a few minutes for the electronics in the monitor to start working at its best with the Overdrive function performing optimally…

Download the Sailboats Ghosting Testmirror 1

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3D Vision Discover Anaglyph Glasses Quick Test

September 27th, 2009 · 1 Comment · Anaglyph Glasses


I’ve finally managed to get a hold of a pair of 3D Vision Discover anaglyph glasses to do a quick test and of course to compare them with a normal pair of paper anaglyph glasses to see if there is any difference. According to Nvidia the 3D Vision Discover glasses are with optimized color filters which should generally improve what you see and minimize color ghosting, although even with normal glasses the result is very good.


Normally you can get the 3D Vision Discover glasses bundled with some games as a promotion, for instance World of Warcraft or Batman: Arkham Asylum, bundled with some new video cards and of course from different trade shows where Nvidia is participating. Unfortunately these are still not available everywhere, so you may have some hard time finding the glasses just to try them out… actually it might be even easier to try the 3D Vision shutter glasses easier that the anaglyph ones as was the case in my country, but anyway. If you can’t get a hold of 3D Vision Discover glasses, just try to get a pair of normal paper anaglyph ones… the results are pretty close.


What you can notice even before putting the glasses on is that they are a bit bigger than the normal anaglyph paper ones and this is realized with the idea to be more comfortable and suitable for different size and aspect of displays. The red and cyan color filters are quite bigger on the 3D Vision Discover and if you take a closer look you’ll be able to find a bit of difference in the tint of the cyan filter, which is actually a bit more bluish here. There is also a very slight difference in the red color filter, but it is much harder to distinguish with a naked eye compared to the normal white paper anaglyph glasses. How this affects things when using the 3D Vision Discover glasses compared to the plain normal ones is a different story, but you should know there is some difference…


If you try the two types of anaglyph glasses one after another quickly you’ll barely notice any difference or not notice anything at all. This is because generally both pairs of glasses do provide quite good results, especially considering they are free or very cheap to get and do not require too much from the user like in the case with the better shutter glasses alternative. You need to take a bit more attention adn then you’ll start to notice where the 3D Vision Discover glasses do provide better results as the difference is actually in the small details. Still these small details are the things that can improve significantly the experience you get form the 3D Vision Discover, so it is important to have an idea what to look for if you are really interested. In general what the 3D Vision Discover glasses do is to decrease the color ghosting you see through the red and cyan filters or at least make it less apparent and annoying to the user. The color ghosting here refers to seeing some sort of red or bluish “shadow” or a “double image” of some objects. So with the 3D Vision Discover you see less color ghosting and if there is a place with some ghosting around a certain object the colors is less brighter and the ghosting is harder to notice… and easier to be ignored.


If you have already tried normal anaglyph glasses you should not expect that much of a difference if you obtain a pair of 3D Vision Discover and the issues caused by the anaglyph technology are still there. I mean that with every pair of anaglyph glasses you will kind of lose most of the color reproduction of the screen and the image you see with have some depth and pop-out effect, but it will seem almost as it is black and white. Still you’ll be able to perceive some colors, but not all of them and although you’ll be able to take advantage of the Stereoscopic 3D technology it is just something to try and then to get your interested in better solutions that of course have their price. You should also be aware of the fact that the anaglyph glasses do tire the eyes more and are not suitable to be work for hours non-stop without taking some break from time to time. And there is some after effect after you take them off, for a few minutes after that one of your eyes will be seeing in a bit colder tones and the other one in a bit warmer tones. So just try closing one of your eyes and then switching to the other to see this effect of the eye actually adapting to the color filter it has in front for some time. Of course after a few minutes without wearing the glasses everything is back to normal and you should not worry about some possible negative effects of that. Just don’t wear the glasses for too long, especially if it is your first time, because this is tiring for the eyes and the brain. After all this is a kind of new sensation that your body has not experienced so far so you need some time to get used to it and then you should be able to get even better results.

Don’t forget that anaglyph technology and the free 3D Vision Discover mode in Nvidia’s driver do not requite special hardware like a 120Hz monitor so you can pretty much try them on your current gaming PC or even laptop. The only requirement would be to have an up to date video card that is Nvidia based and for good enough performance it is best to have a VGA that can provide higher framerates. So still it is good to have a middle or high-end class video card for playing comfortably in more heavy on hardware requirements games…

Here is how you can use the free 3D Vision Discover mode on Nvidia-based VGA…

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