[DIY] Auto-Stereo with Parallax Barriers

Post by **luthor70** » Tue Oct 04, 2011 3:42 pm

Thx for the answere cyber. I just made an interleaved image with 2 different images for the left and right eyes. I think it's a good test, because with a good barrier I may be able to see just one image at a time. I just bought one picture frame and I put the glass between the LCD screen and the barrier, it helps a lot. It seems the more the barrier is set far from the LCD, the less the viewing angle is wide.
I'll let you know when I get better results.

Post by **cybereality** » Tue Oct 04, 2011 9:01 pm

Ok, awesome!

Post by **luthor70** » Tue Oct 04, 2011 9:55 pm

I did play with that stuff all the night. Am I wright to assume that there can be many working barriers and not only one ? I mean different barriers working for different distance between the sheet and the LCD, or between the sheet and the spectator ?
The last print I did, it looked good but only with a very (very very) limited viewing angle. Is it that way it is suppose to be ?

BTW : Does your barrier work equaly from the left to the right of the screen ? I read someone wrote it couldn't work on the sides , is this true ? Thx

Post by **Likay** » Tue Oct 04, 2011 10:16 pm

Different barriers for different monitors = true.
A relatively fixed viewing distance = true.
Very limited horisontal viewing angle = true but there can also be more than one hotspots where stereo is possible. Usually the "centered" viewing hotspot is the best using this method.

Post by **cybereality** » Tue Oct 04, 2011 10:28 pm

Yes, there is not just one pattern. Each monitor can have a different pattern, and even on the same monitor there can be different ones that work. This depends on the thickness of the glass of the monitor and your viewing distance from the screen. So you need to experiment with it to kind something that's comfortable.

Post by **qingdao11** » Wed Oct 05, 2011 6:12 am

Nice work Cybereality

My Resolution is 1280 * 800,Diagonal Size is 15.4 So Dot Pitch is 0.2591mm = 0.0102007874015748 inch
pbb for 1440 = 14.6891
i am using A4 size paper so can any one help me to make the perfect pattern ?

1) Click "File" -> "New"
2) Set the following options:
Width: 32px (or double whatever your ballpark ppb is),
Height: 1px
Resolution: 72 ppi
Color Mode: Grayscale 8-bit
Background Contents: White
3) Press "M" to select the Rectangular Marquee Tool.
4) Press "Control"+"R" so show the rulers. Then right-click the ruler and select "Pixels".
5) Select a 16px x 1px area on the left side of the image.
6) Press "Alt"+"Delete" to fill it with black.
7) Press "Control"+"D" to deselect the area.
8) Click "Image" -> "Define Pattern...".
9) Name it something sensible like "16px barrier".
eg
Can i change Width to 1 px and Height to 32px ?

Post by **luthor70** » Wed Oct 05, 2011 9:55 am

Last night I made 2 barriers with similar results but working with different distance of viewing even though the distance between the sheet and lcd was the same. This make the work quite more complicated.
Could you please confirm that perfect barrier should work as well on the center than on the sides (on the 22" monitor screen) ?

Post by **Fredz** » Wed Oct 05, 2011 2:08 pm

Yes :
http://www.mtbs3d.com/phpBB/viewtopic.p ... 687#p60687" onclick="window.open(this.href);return false;

Post by **cybereality** » Wed Oct 05, 2011 6:02 pm

@qingdao11: Depending on your monitor, you may have to adjust the numbers. So just experiment with it.

@luthor70: Yes, ideally you can get the center and sides of the monitor to work the same.

Post by **luthor70** » Wed Oct 05, 2011 6:20 pm

Thx Fredz, evrything you wrote in this thread is very interesting. As you mentionned the same issue with every 3D technics, it reminded me that I get this issue with my anaglyph glasses, but only if I move my body. If I don't move, the depht at the sides of the screen don't look different from the center, or at least I don't notice it.
I could test the LG optimus 3D last month in a store, and I remember I told myself that the depht didn't work well on the sides. I haven't noticed this on the Nintendo 3Ds, probably because of the smaller size of the screen ?

Post by **luthor70** » Wed Oct 05, 2011 6:41 pm

qingdao11 wrote:Nice work Cybereality

My Resolution is 1280 * 800,Diagonal Size is 15.4 So Dot Pitch is 0.2591mm = 0.0102007874015748 inch
pbb for 1440 = 14.6891
i am using A4 size paper so can any one help me to make the perfect pattern ?

1) Click "File" -> "New"
2) Set the following options:
Width: 32px (or double whatever your ballpark ppb is),
Height: 1px
Resolution: 72 ppi
Color Mode: Grayscale 8-bit
Background Contents: White
3) Press "M" to select the Rectangular Marquee Tool.
4) Press "Control"+"R" so show the rulers. Then right-click the ruler and select "Pixels".
5) Select a 16px x 1px area on the left side of the image.
6) Press "Alt"+"Delete" to fill it with black.
7) Press "Control"+"D" to deselect the area.
8) Click "Image" -> "Define Pattern...".
9) Name it something sensible like "16px barrier".
eg
Can i change Width to 1 px and Height to 32px ?

Hello there. The width value on the tutorial only works in cybereality's case and it must be read as an example. Your should especialy pay attention to the "interpolation" part of the tutorial.

Post by **Fredz** » Wed Oct 05, 2011 6:45 pm

In the case of the LG Optimus 3D, the problem of depth at the sides may come from the content itself. Some years (decades?) ago people at Stereographics (Lenny Lipton) said that for autostereoscopic displays it was better to push the convergence plane out of the screen for best effect, which generates window violations at the edges.

I've experimented this myself with most of the content available for the 3DeeSlide (lenticular lens for the iPhone). I'm not sure it was such a wise decision to do this, I didn't find any justification to this rule.

Post by **cybereality** » Wed Oct 05, 2011 8:01 pm

I have the Nintendo 3DS, and I have tested the HTC Evo 3D, there is no issue with the side of the screen.

Post by **qingdao11** » Thu Oct 06, 2011 7:42 am

I mean that its ok to print horizontal lines instead of vertical lines on A4 paper ? bec it will help me to cover more area of screen

In A4 8.2*11.6 inch paper i can print horizontal 8.2 inch sized lines with 14 pixels?

Post by **qingdao11** » Thu Oct 06, 2011 11:46 am

Thanks Luthor70 and Cyberreality

i tried to understand the Interpolation part
my ppb is 14.6891
so i need to make pattern something like 1 black line and 1 white line with 15px and then 1 black like with 14 px ?
i am really confused ple someone help me..........

Post by **luthor70** » Thu Oct 06, 2011 1:58 pm

qingdao11 : The lines must be vertical at the screen, but you can print them horizontal, then rotate your sheet at 90°.
If you print using a resolution of 1440 your ppb is actualy 14.6891 (assuming your printer can do 1440 in b&w. Read well the doc of your printer). This number only works for your LCD grid itself, but your barrier will not lay exactly on the LCD (it must be set a few mm in front of the LCD (I personnaly put a picture frame glass between them)), the right number is a little bit smaller .. maybe around 14.5 or 14.6. As you can't directly enter complicated numbers( just whole numbers), you have to use interpolation. One 14 and one 15 gives a 14.5. One 14, one 14, one 14 and one 15 give : (14+14+14+15)/4 = 14,25. In this example this would give :
- one black line made by 14 pixels
- one white line made by 14 pixes
- one black line made by 14 pixels
- one white line made by 15 pixels.
Now you have the source pattern, you just have to save it as a motif, then finaly fill your sheet with it. Also the right number may be more complicated, maybe 14.552 or 14.621, so you have to create more complicated series of numbers for the interpolation.
I hope this will help you, but I advice you to read again and again the tutorial, it's well done, thanks to cybereality. Good luck.

Post by **cybereality** » Thu Oct 06, 2011 5:30 pm

14.5px might be close enough, meaning one blank line with 14px width, and a black line of 15px width. However you may need to tweak this further depending on your setup.

Post by **qingdao11** » Fri Oct 07, 2011 12:54 am

Thanks again....i just have 6 papers so i have to be careful...ok today i am gonna print it,very excited...i am going to use Epson Stylus Photo R290 - 5760 x 1440 optimised dpi with 3pl minimum droplet size and other printer is Canon PIXMA iX4000 with 4800* x 1200dpi but i will use R290...

Post by **qingdao11** » Fri Oct 07, 2011 1:25 am

you can go to near by print shop in your city....they will have some better printer...you can print there....very cheap

Post by **Likay** » Fri Oct 07, 2011 5:05 am

True, but it's a pita if you don't know the exact measures for the barrier. In my experience this practically has to be tested several times before you hit right.

Post by **luthor70** » Fri Oct 07, 2011 7:32 am

Just a few questions :
- Do you notice more ghosting with this paralax method than with simple anaglyph glasses ? For me, the answere is absolutly yes.
- Is tere any solution to make a more opaque barrier with a printer ?
- Would you use this more than 5 min, I mean have you ever tried to watch a full movie ??

Post by **cybereality** » Fri Oct 07, 2011 5:35 pm

luthor70 wrote: - Do you notice more ghosting with this paralax method than with simple anaglyph glasses ? For me, the answere is absolutly yes.

There is some ghosting with this method, particularly because its DIY, but its not horrible. I also get ghosting with Nvidia 3D Vision. You can't avoid it unless you use HMDs.

luthor70 wrote: - Is tere any solution to make a more opaque barrier with a printer ?

Make sure when you print, you go into the printer settings and choose "black & white" and the "best quality". That will make thicker lines.

luthor70 wrote: - Would you use this more than 5 min, I mean have you ever tried to watch a full movie ??

I have played games with this, for as long as 30-45 minutes. Not sure I would want to sit and watch Avatar with it, but I guess you could do it. The issue isn't the picture quality so much as that you have to sit in a fixed position. The quality itself is actually not bad.

Post by **luthor70** » Sat Oct 08, 2011 3:24 am

Thx for the answeres cyber. I'll try to play with my driver's printer to see if it can send deeper blacks.
That's such a pitty that the viewing angle is so small because the 3D is really impressive. I would say the main issue is the horrible viewing angle, then the low resolution of the image. I can't imagine what would give this diy with a real HD resolution !

Post by **djemergency** » Sun Oct 09, 2011 9:40 am

I have a macbook pro 13' mid 2010 and would love to get this working. I really don't understand the method of doing this. The screen resolution 1280x800, PPI 113, 13.3 Inch screen. If you can help me out it would be greatly appreciated.

Post by **cybereality** » Sun Oct 09, 2011 10:07 am

You are basically just printing out black lines that will block every other column of pixels. The tricky part is getting it to match your screen exactly. Takes some experimentation.

Post by **djemergency** » Sun Oct 09, 2011 4:51 pm

This is what i got so far. I'm not too sure how much thickness it is for the glass in front of the LCD screen.

Post by **cybereality** » Sun Oct 09, 2011 5:29 pm

That means the lines and the spacing are too small. You have to widen it out a bit:

Post by **qingdao11** » Sat Oct 15, 2011 7:34 am

Hi Cybereality what is your screen pbb ? and which pattern you are using ?

Post by **cybereality** » Sat Oct 15, 2011 10:17 am

Its all explained in the tutorial:
http://www.mtbs3d.com/phpBB/viewtopic.p ... 961#p55961" onclick="window.open(this.href);return false;

Post by **qingdao11** » Sat Oct 15, 2011 12:58 pm

ppb is 15.987401568 so you used 11 lines at 16px and then 1 line at 15px ? last perfect pattern for you ?

Post by **cybereality** » Sat Oct 15, 2011 1:51 pm

qingdao11 wrote:ppb is 15.987401568 so you used 11 lines at 16px and then 1 line at 15px ? last perfect pattern for you ?

Yes, that's correct.

Post by **qingdao11** » Sun Oct 16, 2011 8:33 am

ok
My screen ppb is 14.6891
so i tried 14.5 px but its to small and 15px is too big
then i tried 3 line with 15 and one with 14 = 14.75 still too big
so now what to do ?
can i use 4 line of 15px and 2 line of 14px ? 14.6666 very close

Post by **cybereality** » Sun Oct 16, 2011 11:07 am

Well that would be the same as 2 lines at 15px and 1 line at 14px. If that doesn't work you can try 5x 15px and 3x 14px or something like that.

Post by **qingdao11** » Mon Oct 17, 2011 5:35 am

so can i use 2 lines at 15px and 1 line at 14px ? but its not even....you said that we have to use even number
just one paper left so i want to make a final print....

ya i tried 5x 15px and 3x 14p...its the best so far...almost half screen with blue and red color so i think just have to widen a little bit

Post by **cybereality** » Mon Oct 17, 2011 5:43 pm

Yeah, you're right. It has to be even in order to tile correctly. Forgot about that.

Sounds like you are getting close. Maybe 15 x4 + 14 x2 will work better for you.

Post by **qingdao11** » Mon Oct 24, 2011 10:54 am

i tried 15 x4 + 14 x2 but its not working...bit bigger...when i go back from screen then it turn white but cant see 3d but can see two different image from different points...i am so sad...what to do now ?

Post by **cybereality** » Mon Oct 24, 2011 6:06 pm

Well if you can see two different images, then it can be 3D. You just have to get the position correct so each eye sees a different image (one for left, one for right). Then if you play 3D content, like with the Stereoscopic Player or IZ3D driver, it will be in 3D. If the viewing distance seems wrong you can try flipping the sheet over (so the printed side faces the monitor), or adding a blank sheet in between.

Post by **hlmasterchief93** » Mon Nov 07, 2011 3:13 am

Hey cybereality
Can I watch 3d movie with this setup ?

Post by **jon08** » Mon Nov 07, 2011 10:34 am

Hi! I'm french guy and I saw your video (Cybereality) on YouTube. I read the entire tutorial but I have some questions:

First:
My screen is an Asus VW220D 22" which has a dot pitch of 0.277mm so 0.0109055118 inches. My printer can do 1440dpi so my result is: 0.0109055118 X 1440 = 15.703936992

If I do a patterin of 16px X 1px, it's too big. I have read the part about interpolation, but I'm french and I don't really understand what I must do in order to have a better pattern.

Second:
In France, a piece of paper isn't = to 8.5 X 11 inches but 21cm X 29.7cm (so 8.26771651 X 11.6929133739 inches). Can I do a barrier with this size? Is that the result will not be distorted?

Thank you for your understanding!

Post by **cybereality** » Mon Nov 07, 2011 5:14 pm

@hlmasterchief93: You can watch 3D movies, as long as they can be played with the Stereoscopic Player. So NOT Blu-Ray 3D, but basically anything else.

@jon08: The interpolation means you sort of "fake" a higher resolution. In your case, 16 pixels is too much. So what you want to do is make something like 3 lines at 16 pixels and then 1 line at 15 pixels. So the pattern will look like

| 16px | 16px | 16px | 15px | ...

This will end up being close to 15.75 pixels, which is almost what you need. That actually might work, but you will probably have to tweak it further. But that should give you an idea.