Thats already taken care of. I'm using the IZ3D driver in vertical interlace mode. So I was actually playing Mirror's Edge for like a half hour with the parallax barrier and when I found a good part I would just stop and take a snapshot.

Sweet. How did you find the experience? Would you recommend this over say anaglyph? Im getting keen to print up a big sheet for my 28inch

I thought it looked decent for what was basically a 25 cent piece of transparency paper. Still a lot of issues I need to work out, so don't think I am finished just because I have something playable. It certainly looked better than anaglyph when it was working, but due to a variety of issues its not yet at the point where I could recommend it to anyone. Its still a work in progress.

Found this:
[youtube]http://www.youtube.com/watch?v=A11_M4LqL_8&feature=sub[/youtube]
looks good when he moves the film with his fingers.
How nice it would be if You could just buy some film to stick on Your monitor...

Wow! Nice find. Would be hard to sell lenticular kits since each panel has a different dot pitch it would be insane to support all the different displays. But if people could find a cheap monitor that works well with existing lenticular sheets (like that guy apparently did) then it wouldn't be too crazy to simply buy the monitor that worked with the lens.

I've posted a new video. Finally got that tripod so now I can record and play at the same time.

Still not complete yet but playable:

http://www.youtube.com/watch?v=goPFfIBb9aI

Well done Cyber!!!
Just a couple of questions (interested in a very big project for 52inch TV):
1. Are you still using the monitor in portrait mode, or did you get it working in landscape?
2. is the interlacing on the screen just every second column of pixels, or is it using multiple columns of pixels?
3. Is the barrier layer sitting flat against the screen glass, or is there another layer to make it further from the screen?
4. Have you considered using wider lines for the black to get better viewing angle? I'm aware this will make the image darker, but it might make it better to use.
so have the columns you are printing:
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
5. I'm considering doing a checkerboard so that I can play Avatar on xbox360 as:
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
BWWBBBBBWWBBBBBWWBBBB
BWWBBBBBWWBBBBBWWBBBB
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
BWWBBBBBWWBBBBBWWBBBB
BWWBBBBBWWBBBBBWWBBBB
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
BBBBBWWBBBBBWWBBBBBWW
What are your thoughts?

Yeah, I am using the monitor in portrait mode. Landscape cause some pretty bad sub-pixel ghosting. There may be a way to fix this but it would limit the type of content that could be viewed. The interlace pattern I am using blocks every other pixel, so it is a 1 pixel barrier. I have it taped directly to the monitor. It seems the glass itself generates enough parallax for it to work. I have considered making the lines thicker to increase viewing angles. I haven't explored this idea much, but it should work in theory. I still want to work on this project more but I keep getting distracted. Doing a checkerboard pattern would be a lot more difficult but I guess it could be possible.

I have managed to create a parallax barrier for the sony PSP (3000, not Go).
I'm not sure if the scaling of the printer I've been using is out, or if there is some other issue, but I couldn't just set the resolution as I expected. What I found worked is using GIMP and set the resolution to 128.8 pixels per inch (for anyone not using photoshop, I recommend this application as it's one of the best open source applications out there). This creates a barrier that is almost perfect for the psp when held at arms length.
I printed on cheap transparency paper on a laser printer at work, and there was a little smudging of the toner, but good blockout from the printed lines.
There are some issues though:
1. There is about 2mm between the LCD and the plastic in front of the screen on the psp. This means that for optimal viewing, you need to hold it at about 2 feet from your face.
2. The psp screen is a bit too dark for this to work effectively. I converted one of the screen shots from avatar that Neil had uploaded, and had to make the brightness 150% before it was really viewable.
3. Obviously of no fault of the psp or this solution, but a general fault with parallax barrier solution with only two images, but you must hold your head very steady as shifting more then a couple of cm either way will cause ghosting. More then about 3 cm (half way between your eyes) will reverse the image causing headaches. One thing that I will try is with a 2/3rds barrier and 3 images when I get a chance. my calculation indicates that this should work well on the psp at about 12 inches from the screen, so long as it isn't just too dark to see anything.

All in all though, I'm pretty pleased. I would love to see a game to implemented vertical striped L/R stereoscopic views on the PSP.

Where to from here:
1. See if I can implement 2/3 barrier with 3 images.
2. See if I can create barrier for something bigger... checkerboard for 52" screen

I've recently become interested in the parallax barrier way of creating a cheap, simple (ish) 3D display. I stumbled across this forum in my research and figured I'd share with you what I have so far. I hope you'll forgive me for resurrecting such an old topic, but I thought this post belonged here. I've created a small C program that generates a parallax barrier for you, based on the equipment you have at hand. This includes the DPI of the printer you're using, the pixel width of your screen, the width in pixels of your display, and the height of your display. My program will then generate the optimal barrier for your display.

This method isn't perfect, it doesn't incorporate the possible stretch of your transparency sheet, nor the minor imperfections in your printer. After toying around with it for a while, I found a 0.2295mm dot pitch to be the closest to my MacBook Pro 15" screen, which at 1440x900 has a .231mm dot pitch. It still isn't perfect (I can make an image of about 12cm wide appear in 3D), which I'm attributing to the fact that this dot pitch just happens to be very incompatible with 300, 600 and 1200DPI printers. For this reason, my program also outputs some statistical information, to help you assess the quality of the produced image.

I'm still working out a good way to determine what you should do to modify your barrier to be pixel perfect. I'm currently working on the math of alternating-pixel-images, which show more or less banding when viewed with one eye depending on the quality of your barrier (more banding means a more incompatible barrier).

The code uses libpng to create the output image (which can become quite large, in the range of 10k pixels x 10k pixels). You must print this at the DPI you specified when generating, otherwise it won't work. Because it uses libpng, you must also link to it when compiling. On my Mac, this boils down to something like:



Then run ./parallax and read the instructions. (Example commandline, for my Mac: ./parallax 1200 0.2295 180 1000 macbook-example) This should work fine under both MacOSX and Linux. If anyone is willing to put up binaries, or make a port to Windows, that's fine and would be welcomed. The code is under a do-whatever-you-want-with-it license.

Any feedback, and most certainly improvements, are highly welcomed!

Ok cool. Nice work. I have pretty much abandoned the project but I still want to come back to it some days. Its fun stuff. If I get bored maybe I will port the source to Windows.

Just a quick thought ... what if one would manufacture a parallax barrier for each color, R, G & B and overlay them ... wouldn' this give better results ?

EDIT: I've made a little slide show to make my idea more clear. I think you would loose less light and maybe improve the color ghosting ?

It's an interesting idea, but it would require even more alignment. Getting a barrier to align is hard enough as it is. Also, you'd need a color laserprinter for that idea to work, and those usually don't go much above 600dpi. I've found that for certain pixel pitches, 1200DPI is a must (in fact, all the ones I've tried were horrid at anything less than 1200DPI).

It's unfortunate that these barriers are so hard to get right, because they yield very decent autostereoscopic results once you do get them right. I've managed to get some good results out of my barriers anyway. But when looking at your screen right-way-up, the bounding box wherein you get good results without ghosting or color bleed is about 2-3cm wide, and maybe 15cm deep.

I have a cheap chinese tablet coming in, with an 800x480 screen and I'll be trying the barrier technique on that one as well. Not sure when I'll get around to it, as I've also just purchased some Elsa Revelator glasses to fool around with.

Hi guys, I thought I would give this a try myself and since I dont have a quality printer I thought (could this be tried using a transparent photoshop gif with the barrier printed?). I Used a interlaced picture someone put up here, loaded the barrier in a second layer and something is going on but not wuite 3D. I can see two positions for the Image basically if I move the barrier sideways, but can only see one position at a time. Am I dong something wrong? I read at the beginning of the post that it is "Opaque" my lines are all black, so do I just need to give the lines a bit more transparency to see both positions at the same time?

You need a good quality printer, at least 1200dpi and preferably laser, in order to do this.

Thanks for the quick reply. What I meant was CAN I see the 3D effect on an interlaced image if I just put the Parallax barrier in front of it by doing it in Photoshop. I have done it and I don't get the 3D effect, it works in that it shows 2 positions angles for the image if I move the barrier one side or the other, but the Interleved image only looks 3d if I use shutters, I think the point is to do it without them.

I want to know if anyone has tried it since I would be able to come up with the barrier match beforehand in Photoshop and then just print the one I know will work.

If you are asking if this effect can be simulated in Photoshop, then no. You have to physically print out the barrier pattern and place it upon the screen for it to work.

No wonder it didnt wok lol. Thank you for your patience

Will give it a go with printing then.

Thanks!

The print also needs to match the displays pixels perfectly to have stereoscopy through the whole screen. On onepixel basis i managed to have about 7 centimetres of good stereoscopy before the image doubled/switched. It was just luck that my printers native res was so close to the screens. Another way is of course increasing the pixelbase which of course will give more visible lines.

Thanks guys. I actually have two 8" LCD's:

Pixels: 800(W) x 600(H) pixels
Active area: 170.4(W)x127.8(H)
Pixel Pitch: 0.213(W)x0.213(H)

I opened one up and put it in front of the other, can I make the second one show a barrier and have it work? I know printout is easier but was trying to have something like a 3d 2d monitor thing going on.

Can it work? Or maybe I just screwed up that second monitor lol.

If the front monitor is translucent enough to show the back one, then I guess it could work. I know some prototype monitors have been shown using this method so it clearly works (at least using the right type of LCDs). This would also make alignment a little easier since its a 1:1 ratio. Although you will probably still experience the sub-pixel ghosting issues that I spoke about. The only way to fix that was the turn the monitor into portrait mode. Not sure if that would work using an LCD as the barrier.

Hello everybody!

I've been reading this full thread and I'm very interested in beeing able to convert my lcd into auto3d. My main interest is on lenticular sheets, but at first I would try with parallax barrier. So browsing the web I found someone that was succesfull on a 42" lcd with 9 views barrier, so how is this possible?

I would say that he is using a bitmap mask that has one clear pixel column followed by 8 black:
BBBBBBBBWBBBBBBBBWBBBBBBBBWBBBBBBBBW
BBBBBBBBWBBBBBBBBWBBBBBBBBWBBBBBBBBW
BBBBBBBBWBBBBBBBBWBBBBBBBBWBBBBBBBBW
BBBBBBBBWBBBBBBBBWBBBBBBBBWBBBBBBBBW
BBBBBBBBWBBBBBBBBWBBBBBBBBWBBBBBBBBW
BBBBBBBBWBBBBBBBBWBBBBBBBBWBBBBBBBBW

The trouble is getting the 9 images required and generating the composite of these. I recently found the following which is a gif with 10 frames (well, it's more then that to get the complete cycle, but 10 unique images) which could be used:
http://www.gbeye.com/images/b2bproducts ... -480px.gif
If you get that image, increase the size by a factor of 9, overlay the above, and then splice the frames 1-9 with an offset of 1-9 pixels (depending on frame), it will create the picture to be displayed on the monitor.

This will, however, create a very dark picture and it may be better to use every 2nd frame and only a 5 view image (stereo viewable from 3 positions).

So this is limited to specially composed images, isn't it? Cause stereo rigs only record from two different views.

Anyway, he also mentions something about converting a lcd to 3d for use with polarized glasses, and I also read something about that in a study paper. Where could I find some more info to do that?

The way to convert an existing lcd-monitor into 3d is using a quarterwave retarder (the result is circular polarization and the technology is called x-pol or u-pol). It's best done on industrial level though. Imagine yourself cutting all those stripes by hand and then manually attach them to the screen.....

As for android78 i'm also uncertain what software the author uses to make it work....

One way to make autostereo with parallaxbarriers would be just making one without matching the screen (which is very difficult if you don't have a very good laserprinter) and then make a calibrationsoftware on subpixellevel for the screen+barrier. Coloranomalies could also to some degree be adjusted away in the algorithm i think.

What I've seen about polarization is as simple as putting a piece of cellophane covering one half of the screen. But the screen has to have polarization filter and also the glasses have to be adequate to the polarization angle that is output from the screen.

About parallax barriers, well, it's something I'll try if I find the exact values that have to be printed, then I'll go to a professional printing store to assure a precision printing.

Lcd-monitors are already linear polarized. Applying a piece of cellophane (substitute for qw-retarder) doesn't make the screen 3d. If you cover one half of the screen with a retarder the light from the retarder will be circular polarized and the other linear. Linear polarized light easily goes through a circular polarizer and vice versa (means neither circular, linear or a combination of glasses will work). However if you apply two retarders on each half of the screen you can use circular glasses like real-d but in this matter you'd do just as well freeviewing crosseyed. I might misunderstood though.

I may not have explained myself well, this is what I was talking about.

Lol! and yes: This is simply a more complicated way of seeing crosseyed.
Many people would find it helpful though since each eye only sees the correct corresponding view. The polarizers and glasses simply helps blacking out the image that's not needed for each eye. Still you need to consider that the brain has to learn a new way of focusing, just like when trying to view crosseyed.
In my experience the cellophanes i've tried had more quarterwaveretarder-properties but practically worked out pretty bad. It's quite cool they found a fabric which have almost perfect halfwaveretarder characteristics.
I assumed that cellophane is closest to qw and that's why i promted two was needed (shifted 45° to the left resp 45° to the right). The final result using qw's is viewed with circular polarized glasses instead of linear.

I put the math for this up here:
http://www.mtbs3d.com/phpBB/viewtopic.php?f=26&t=1467&start=42

Hope this works out for you. Let me know if you need help with the math.

I've just read you guys' great approaches, and wonder if any manufacturers develop parallax barriers film for specific device (e.g. iphone 4) and attach device that helps adjusting vertical pixels to match with film's LR position and an app that calibrates screen and demonstrate auto-stereos.

I don't know about parallax barriers, but there is a lenticular sheet for the iPhone which is called 3DeeSlide which comes with a stereo image viewer available on the App Store (3DeeView).
See there : http://www.spatialview.com/product/3deeslide/

This is great! Thanks Fredz! I need to buy it.

You’re welcome.
And don't hesitate to post a review if you happen to buy one...

Ok, I have revived this project yet again. Now I have finally gotten the full-screen implemented in standard landscape mode. Previously I was just using the monitor in portrait mode with windowed games. Now full-screen, full-resolution 3D gaming is a reality. I was able to play about 2-3 hours of Half-Life 2 with this setup, its is actually working. Yes, you heard me right. Glasses-free 3D gaming for under $1 dollar!!! I will be honest, I did get a little queasy by the end and I had to stop playing. That just shows how well it works. Now, it is not perfect. There is a significant, but acceptable, amount of ghosting going on. This is due to the way the LCD sub-pixels are arranged. If I use the monitor in portrait mode there is nearly no ghosting, but this is not really a viable solution for playing games. So ghosting is inevitable with this setup, but its probably not that much worse than, say, anaglyph. And no, it still doesn't match a real 3D monitor with 3D glasses, but it comes pretty darn close. Resolution-wise its about on par with the Zalman solution, although there is some graininess of the image you don't get on the Zalman. However in terms of brightness/color-reproduction it is actually better than Zalman (or maybe even shutter glasses). This is because you are not wearing any polarized glasses, which inherently tint the image (even the "transparent" side). So in terms of brightness/color quality, I found it to be brighter and have more natural color than even the Zalman 3D monitor. That is not to say the picture quality itself was better. With the parallax barrier it suffered from this graininess and increased ghosting, so it was still worse overall. Something like the Panasonic 3D plasma with 120Hz shutters will blow this away in terms of picture quality. However as a cheap DIY mod, this thing does wonders. The 3D effect itself looks pretty convincing and, if it weren't for the ghosting issues, grainy picture quality, and the pieces of tape in the middle of the screen, it could probably rival solutions costing $500 or more. I don't think I am going to get the quality much better than this. The problems I am facing are more of technical limitations rather than anything I am in control over. If I worked really hard I could probably get the ghosting down a little bit, but it is in a playable condition. The only thing I am trying to figure out at this point is some convenient way to attach and detach the barrier quickly (as of right now I have it taped at like 20 different points, it takes a while to put on or take off). If anyone has suggestions, please let me know. I am planning on putting together a full tutorial in the next couple of days, but let me just leave you with an image now so you guys can see the quality. Keep in mind that this image does not come close to the actual experience, but it is the best thing I could come up with. This is because the optimum viewing point is too close to the monitor to take a picture (although the video does a better job of representing the effect).

Cross-eye 3D image (can save as jps if you want):


Here is a video of my testing image, just to illustrate the ghosting and viewing angles:


EDIT: Ok, so I tried to take some better stereo photos. Again, the ghosting is bad, but its not *that* bad. It looks way worse in the photos, not sure how I am going to document this. But these images should give you guys at least an idea of the quality.







Also, the more I play with this setup, then more I am liking it. For some strange reason, the 3D effect almost seems more immersive than the Zalman 3D. I know that doesn't make sense, it should (at best) look the same. However something about it just looks really impressive. Maybe the dimming effect of the polarized glasses really makes that big a difference. I don't know. But its almost as if it looks more 3D. I'm not making this up.

Very cool. Maybe once you get the formula down you can a print shop to make a big one?

Yeah, I am looking into that now. Seems the biggest common size is 11"x17", which would almost fit my 22" monitor, but might be a little small for anything bigger. There are also large format transparency rolls, I just have to figure out if any local printers have them available. Even so, I am not entirely sure the pattern I have will work larger than 6" width. I seem to get ghosting along the edges, which is somewhat helped by having 3 sheets side-by-side (so I can adjust the phase manually). I have been trying to get a more accurate print, but I may have reached the limitation of 1200dpi, unfortunately. A print shop could have a higher-res printer but it will be difficult to go back and forth testing this to get the right pattern. Not sure if there is a better solution, though.

@cybereality

hi, i'm closely watching your work and i'm totally in love with it. i think the reason you've used 2 separate sheets at the left and right sides is to manually adjust them independent of the center piece to reduce ghosting, am i right? Well how about changing the pattern to reduce ghosting? the distance between the vertical lines of the barrier may be narrow in the middle and it may slightly grow when going to the edges. That may solve the ghosting problem but i think the driver must support this too. i don't think the vertical interlaced mode of iz3d presents any settings to compensate the new pattern layout but if it does somehow, maybe they add it as a feature in the future or even a parallax barrier mode which you can set the details, that maybe the way to go.

What do you think about my idea?

pattern example (think of it on a bigger scale with correct calculations):

@vpamir: Well, the reason I am using multiple sheets is because I do not own a large format printer. 8.5" x 11" is about the largest I can print, so multiple sheets are unavoidable. I initially thought the pattern had to change as it reached the edges (similar to your sample), but people here told me that is not the case. Supposedly the parallax barrier should have a fixed width for each line (ideally about the width of one physical pixel on the screen, or just slightly smaller). Anyway, I need this to be compatible with existing software, namely the iz3D driver but also the Stereoscopic Player, YouTube3D, etc. Its pretty useless if it only works with specially made content.

@Okta: I found that my local Kinkos will print on transparency, however they don't supply the sheets. I would need to buy them separately. The largest their printer supports is 11"x17", which could work for a 22" monitor. I can get those size sheets for about $1 a piece in a 10 pack (cheaper if I buy more). However the Kinkos printer is only 600dpi, which may not be detailed enough for this project. When I print at home at 600dpi, even with a working pattern (the same one used in the video/pics) it comes out weird and doesn't work. So I might have to find somewhere online that can do this at good quality (preferably better than what I have at home).

Ok, I have made a breakthrough. With this new method I have reduced ghosting to about 5% or less. After reading some whitepapers I realize the ghosting effect I was getting wasn't due to the pattern going out of phase, but rather sub-pixel bleeding at off-angles. If you are directly in front of the pixel everything is fine, but as you look toward the edge of the screen you start to see bleeding from adjacent sub-pixels. To fix this I am using 2 identical barriers layered one on top another. This has the effect of collimating the light coming off the screen and thus ensuring that light is emanating mostly perpendicular from the screen. This greatly reduces the sub-pixel bleeding I was seeing. Now it is not without some drawbacks. Because I am using 2 transparency sheets, the image is darkened somewhat (even just using 2 blank sheets does this, irrespective of the barrier printout). In addition, since light is being blocked at off-angles, this reduces the overall brightness of the image somewhat (although it was bad, ghosting brightness anyway). All in all, it is a marked improvement from the single sheet method. I still have some optimizations to do, and I think I can reduce the ghosting even further. However, where it is now in terms of ghosting is comparable to professional solutions.

You can see this illustrated in my latest video. The red/blue sample image I was using for testing was actually the worst possible thing I could have done, as it masks the sub-pixel bleeding issue (since red and blue are on the outside of the RGB pixel components). I still used it for the video, so you guys can compare to my earlier videos, but I am now using a simple black/white striped pattern which is way better for testing (you will see at the end of the video). Ideally the left image should be all black except the words "left" in white. The right image should be all white, except for "right" in black. You will see it comes pretty close, with barely any cross-talk on the text. It is very difficult to get pure white with this setup (its sort of tinted between yellow and cyan) but with a full-color image this is not so bad. Black is also not pure black, but fairly close. Hopefully I will be able to improve this somewhat.