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3D Multi-touch Table - GSoC Idea
Posted: 30 March 2010 03:39 PM   [ Ignore ]
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Hello everyone smile To start I would like to introduce myself. My name is John-Nicholas Furst, I am an engineering student at Boston University. I wanted to get some feedback on my project idea before submitting the official proposal later.

Note this is just a first draft of the project, I will be adding the more nitty gritty deals to the proposal at a latter date (probably tomorrow) I am just so excited and interested in feedback that I wanted get something down in the forums to get started.

The first part of this project is to replicate a setup somewhat similar to a Microsoft Secondlight.

If you are not familiar with this research project, I will quickly describe it here. Think of a Microsoft Surface, now add the feature of the table being able to project images onto opaque objects held above it. Now this is hard to picture until you see it, but basically this allows for layers of information.

There is the display on the surface of the table, and this invisible secondary display above the surface that only becomes visible when there is something there to diffuse the light enough to capture the image instead of letting it just go up into the air.

Now if that was not already enough of a challenge hardware and software wise, I want to up the ante and make the entire thing 3D.

So this basically would involve having a second set of projectors calibrated on the surface, and having all of the projectors have the proper polarizing filters to make it pump out beautiful 3D.

So that is the very simplified idea. Again I will add the tech specs later but just to give early responders an idea of proposed materials, I am looking at a DSI setup with Endlighten, four projectors (running at 60hz), 2 for the regular surface and above surface projecting, and the other two to make 3D possible on both the surface and above surface displays, a sheet of Polymer Stabilized Cholesteric Textured (PSCT) liquid crystal to control surface transparency (this is basically the material you see in privacy areas or sometimes interrogation rooms, it is diffused under normal situations, but when a current is applied to it, the molecules align themselves and cause the material to become transparent), two webcams for tracking,four shutters(capable of 60 hz) for the projectors, and of course some computing power to bring it all together.

It would also be possible to add in rfid and Bluetooth connections to make it more Surface-esk but that is not really the point, the point is to develop code to deal with 3d multi-touch, deal with multiple layers of multi-touch, and provide documentation as to how to make this elaborate beast.

So what do you think?

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Posted: 24 March 2010 04:02 AM   [ Ignore ]   [ # 1 ]
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What I think is you have a very great idea when it will become reality as you have the technical planning also. Sorry pals, I can’t give technical suggestion but Good Luck. Waiting for the progress of your project. Stay up to date in this forum :D

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Posted: 24 March 2010 04:03 AM   [ Ignore ]   [ # 2 ]
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Well thank you for your support smile

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Posted: 24 March 2010 04:03 AM   [ Ignore ]   [ # 3 ]
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First off I think your nuts. Second, I think your crazy amazing. The idea is great but definitely has plenty of pitfalls if something goes wrong. I can’t wait to see your spec sheet on this. How would you make the table 3D with polarizing filters? Would it put out an anaglyphic image that you’d use 3D (ex: red/blue) glasses to see? I don’t know much about polarization to fathom how it could be used for 3D imagery but I’m sure your spec sheet will enlighten me. Good luck!

Also for anyone who doesn’t know the Microsoft Second Light, here is a cool video that does a quick example of what Furst is describing.
http://www.youtube.com/watch?v=XfzplPIrzjY

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Posted: 24 March 2010 04:32 AM   [ Ignore ]   [ # 4 ]
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that video is exactly what I am describing. To create the 3D effect there are many possibilities. You mentioned the anaglyphic method (red, cyan), that is the easiest however it limits the color range of applications. So I will not be using that method.  Next we are into the world of polarized lenses. There are a couple basic options here, two common ones are linearly polarized lenses or circularly polarized lenses. The current spec is polarizing will be done with circularly polarized light. 

Here are some diagrams about polarization for use in 3d stolen from wikipedia and other sites:

basic linear polarization: 3-d-glasses-polarization-new.gif

difference in types of polarization (linear vs circular): Linear_polarization_schematic.pngCircular_polarization_schematic.png

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3-d-glasses-polarization-new.gifCircular_polarization_schematic.png
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Posted: 24 March 2010 04:35 AM   [ Ignore ]   [ # 5 ]
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from wikipedia:

Linearly polarized glasses

To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through orthogonal polarizing filters. It is best to use a silver screen so that polarization is preserved. The projectors can receive their outputs from a computer with a dual-head graphics card. The viewer wears low-cost eyeglasses which also contain a pair of orthogonal polarizing filters. As each filter only passes light which is similarly polarized and blocks the orthogonally polarized light, each eye only sees one of the images, and the effect is achieved. Linearly polarized glasses require the viewer to keep his head level, as tilting of the viewing filters will cause the images of the left and right channels to bleed over to the opposite channel – therefore, viewers learn very quickly not to tilt their heads. In addition, since no head tracking is involved, several people can view the stereoscopic images at the same time.

Circularly polarized glasses

To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through circular polarizing filters of opposite handedness. The viewer wears low-cost eyeglasses which contain a pair of analyzing filters (circular polarizers mounted in reverse) of opposite handedness. Light that is left-circularly polarized is extinguished by the right-handed analyzer, while right-circularly polarized light is extinguished by the left-handed analyzer. The result is similar to that of steroscopic viewing using linearly polarized glasses, except the viewer can tilt his or her head and still maintain left/right separation.

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Posted: 24 March 2010 11:11 AM   [ Ignore ]   [ # 6 ]
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Hi John Nicholas,

From a technological perspective I think it’s a great idea, for it is combining two commercially growing concepts into one. However, the effect described by you and shown in the video can be achieved with software on a normal M$ surface. (placing a piece of acryllic on the surface, letting the software identify the position and projecting a different image an that location). So unless you have a great application in mind to actually use the multiple layers and added depth it is not something a lot of people are going to build/buy, for the simple reason that it would become too expensive. (or I’ve completely misunderstood your idea, and you’re actually trying to build a fully 3D screen with 3D touch and finger tracking :D, allowing real time 3D modeling. which of course would be awsome). So the question would be: what are you planning on using it for?

regards,

Marcel

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Posted: 24 March 2010 11:25 AM   [ Ignore ]   [ # 7 ]
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The idea would be for full 3d Screen and 3d touch. The most expensive components of this setup is obviously the four projectors required for the setup. However some people do have this available to them, and to my knowledge no on has done this with full 3D on the screen and above it so I believe that this could be a new innovative way for multi-touch to go, and like always we will find more economic approaches to this solution down the road. I really feel this is a way for the open source = multi-touch community to start leading in innovative designs.

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Posted: 24 March 2010 11:34 AM   [ Ignore ]   [ # 8 ]
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This sounds like it would be a very difficult project, do you have any prototypes or previous research you are building off of for this or are you planning on doing it all from scratch? I wish I had your funding! rasberry

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Posted: 24 March 2010 11:41 AM   [ Ignore ]   [ # 9 ]
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I have background in 3d research and computer vision and have a multi-touch wall setup here in my lab. I also have about 6+ years of experience with c/c++. I have been using ccv since last summer and have rebuilt and recompiled it myself to fit my own research needs. I hope to find a cheaper way to do this also after I perfect it.

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Posted: 24 March 2010 12:11 PM   [ Ignore ]   [ # 10 ]
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so the general idea/setup would be something like this: (excuse my crude ms paint drawing, i’m at work right now and it’s the only thing i have)

Normal P1: your normal surface projector
Normal P2: projector focussed above the surface
3D PL and 3D PR: two projectors with polarized filters focussed on the surface to achieve the 3D effect above the surface.

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Posted: 24 March 2010 12:40 PM   [ Ignore ]   [ # 11 ]
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yes that is a great basic setup photo however both the normals will have polarizing filters on them to get 3D on the surface as well

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Posted: 24 March 2010 06:26 PM   [ Ignore ]   [ # 12 ]
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hello, ambitious and interesting proposal, I have been working for some time 3D projection with passive glasses and tried to play with mirrors and 1 single projector to give the angular difference and reduce costs (of course this requires that the projection is made divided into 2, calibrated and perform the shift by software to control the depth), is also the possibility to perform it with an active filter on the projector which is simply a filter q changes polarity to induce an electrical current.

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Posted: 24 March 2010 07:02 PM   [ Ignore ]   [ # 13 ]
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I am always interested in hearing how others are doing 3D projection. How are your results? Do you feel that your method with one projector works better than my proposed method involving two for each layer of information

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Posted: 26 March 2010 08:46 AM   [ Ignore ]   [ # 14 ]
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Hi,

I’ve been thinking about your idea, and I really like it. I made an other drawing (again using the amazingly versatile Ms Paint) of the basic setup I think you want to use.
if I had the money to build one I would, but I’ll be stuck with my FTIR LCD for now :p. on the matter of software, you would need 3D finger tracking (maybe CCV could be modified to do that, but I’ve seen other software capable of doing that) sending the 3D blob information to a 3D SDK (unity3D or something like it) right? Building the hardware and developing the software is a enormous task. With how many people are you working on this project and how long do you have to develop it?

About Daniels idea to use one projector to project a 3D surface, wouldn’t it be possible to use only 2 projectors, each using some kind of Dual Polarisation filter, or 2 liquid-crystal polarizing filters (alternating the polarisation of the projector, or blocking the image when both are on) it would eliminate two projectors and the shutters, cutting the cost, while maintaining image quality. (assuming you are using >100 Hz projectors).

regards,

Marcel

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Posted: 26 March 2010 09:43 AM   [ Ignore ]   [ # 15 ]
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I love your drawing!!! I will comment on it more when I have a second ... (I am currently teaching high school chem classes, and just checking the forums in-between periods...) but I will comment on it more when I am finished

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Posted: 26 March 2010 01:53 PM   [ Ignore ]   [ # 16 ]
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Sounds really interresting.  Very big project idea for a single person in one summer though! 

Do you have funding and vendors to get all the required hardware and materials (like where to you get the PSCT LC)?

My other concern would be about the 3D on tabletop.  I’ve worked with passive stereo projectors using polarization quite a bit before, and I think the viewing angle might be problematic.  Even with a vertical display and polarized glasses, the 3D effect quickly becomes distorted and funny looking if you look at it from too wide an angle.  With tabletop displays we have a much wider viewing angle by default. Even regular (non stereo) “3D” perspective projections look wrong on a tabletop display.  There is a great paper by Nacenta et. al. in the proceedings of tabletops and interactive surfaces 2009, about this, and why orthographic projection is really a better option for tabletop displays.  So I’m worried stereo 3D wont look correct either or even worse.  (Try just running a simple OpenGL app with a teapot model or something on a tabeltop/horizontal display and walk around it while looking at it, you’ll see what i mean).

I’m not tying to say this is a bad idea, it sounds really cool!  Just wanted to give some constructive feedback.

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Posted: 26 March 2010 03:11 PM   [ Ignore ]   [ # 17 ]
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Of course, constructive feedback is what I am looking for here. Thank you! I will setup a some sort of tabletop 3D setup here this weekend / early next week and take a look at the effect your noting. Do you have a link to this paper, I am interested in reading more about it. This project is all about creativity in its design and use of creativity to overcome obstacles. So I may have to research more how to get a better 3D effect.

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Posted: 26 March 2010 03:57 PM   [ Ignore ]   [ # 18 ]
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Actually the first author is mark hanckock, my mistake, miguel was the one who presented it though.

http://hci.usask.ca/uploads/163-projection-camera-ready.pdf

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Posted: 30 March 2010 10:13 PM   [ Ignore ]   [ # 19 ]
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im also looking for new methods to get 3D - i found this article from THG very interesting:

Build Your Own: Wall-Sized 3D Gaming,
http://www.tomshardware.com/reviews/3d-polarized-projector,2589.html

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My DSI Project:

DSI Table
Proj.Surface: 7D006 on top
2x PS3 Camera from Peau with 850BF & 3.6mm lense
Endlightend XXL (10mm)with 850nm LED strip

Projector: SANYO DWL100 ~ 950€

PC:
Core i5, 8GB Ram, HD5850

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Posted: 09 April 2010 01:19 AM   [ Ignore ]   [ # 20 ]
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Almost done writing up my proposal! I will post it here when it is submitted smile

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