Rear DI, 45 x 60 cm screen (29 ‘) , a simple and cheap setup. fiducials and blobs, with plans! 
Posted: 23 March 2011 07:28 AM   [ Ignore ]
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So following my previous thread,
rear Di setup, issues and advices ,
I decided to make some plans and show them to you.

I am currently living in Denmark.
This setup was meant to be the simplest and cheapest one could do to use fiducials and blobs.
It is also meant to be very stable (kids could play with it...).

screen: 45 x 60 cm. height: 85 cm .

These are the items I used:

Screen: (from top to bottom)

- transparency sheet (that protects the drafting paper)
- drafting paper
- normal acrylic 5 mm, 50 x 63 cm. (used screen size: 45 x 60 cm ).  Total : ------- 20 euros.

Table top:  3 mm hard smooth wood to be easily painted
MDF 1cm .

Table structure:

4 MDF panels, 67 x 85 x 1 cm .
1 MDF panel, 65 x 65 x 1 cm .  ------ 10 euros

Screws, etc.  ------------------------------ 20 euros

Projector:  any one you have or you can buy second hand. Mine, benq DSP,very good, but really not short throw: 200 euros
Mirror: any not too thick one. 
Leds: 850 mn infrared leds.  could get 200 for 37 euros. used 100 :  ------------- 19 euros.
some resistors 1 euro.
Power supply : ATX from old computer: free or say, ------------- 20 euros.

PS3 eye, extracting the ir filter and installing 2 exposed photo negatives.
Keeping the original lens mount (that makes the height of the table to be 85 cm, since i did not want to use
mirror with the camera (simplest setup… grin ).  ------------------- 30 euros

i do not include the computer, as i am using the one i had.

Total amount is :  30 + 20 + 20 + 20 + 10 + 20 + 200 = 320 euros ( 450 USD )

I attached some plans of the setup, see the thread link above to get some pictures of the “draft” setup.

Thank you to all of you, this forum was THE reason I could do this.

Of course it is not the best setup, but it looks and perfoms really good.
Hope this helps somebody as I was helped here.

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tangibleX-01.jpgtangibleX-02.jpg23032011.jpg
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Posted: 15 June 2011 05:56 AM   [ Ignore ]   [ # 1 ]
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Hi Miguel.

I am currently building a table and try to combine LLP with Fiducial recognition. I use a 8mm glass as touch surface. Since I want to have Fiducial support, I have to put the diffuser on top of the glass. Unfortunately, I did not find any diffusing foil/material that is sturdy enough for touch input and marker movement on top. Seems, that you used a transparency sheet to protect the drafting paper/diffuser. Can you tell me some more about that?

Regards,
Adrian.

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Posted: 10 July 2011 09:47 AM   [ Ignore ]   [ # 2 ]
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that’s cool Miguel,

How your IR led strip brightness quality when placing 45cm away from the top, did you get good blob? is there any issues when placing overthere? does it need to avoid the angle that reflecting to the camera?

 Signature 

MY GEARS........

Rear DI Table:
Acrylic 10mm
Rear Projection Film
Benq515Shortthrow
PS3EYE
IR Illuminators
CCV1.3MOD
HIDDriver

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Posted: 10 July 2011 07:53 PM   [ Ignore ]   [ # 3 ]
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Hi Adrian and Splash,

LLP and fiducials i think can be very tricky bacause of all the shasowing happening when fiducials are placed in the table. For this setup i made, i use only the diffuser, as diffuser and as projection surface. There is a transparent plastic sheet on top to avoid scratches over the diffuser. It is as those transparency sheets that were used with those old projectors that could project what we were writing over those sheets. Thin, transparent and quite hard.

@splash: my blobs quility was very good, 45cm was by trial and error the best place to put them. The issues you will find is that you do no have exactly even illumination. And, yes, i really had to avoid those led reflections on the camera. This is a main problem when you have the diffuser on top and an acrylic or glass that has some reflection.

Still looking for some anti.glare material.

i just made a new setup and sofware, check:  http://www.tangiblex.net

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Posted: 11 July 2011 03:03 AM   [ Ignore ]   [ # 4 ]
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Hi Miguel.

Thank you for your reply. Meanwhile I found a good diffusion foil which is pretty sturdy and cannot be easily scratched. I tested about 20 different kinds of foil. This one is the best.
I glued this projection foil on top of my sheet of glass and it worked pretty well.

It can be found here (do not take the contrast model, it is NOT sturdy): http://www.ifoha-klebefolien.com/en/special-films/projection-films/projection-film-digiline-white/

Right now I am working on passive (not electrified) Fiducial recognition in my LLP setup, which is pretty hard. Thank you for mentioning the shadowing problem - I use 4 lasers to avoid occlusion of fingers but since fiducials are a lot bigger, this could be a bigger problem.
Maybe I have to switch to active fiducials…

Bye the way: your tangible objects look good! What kind of material is this? Did you just glued printed fiducials under these objects?

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Posted: 11 August 2011 02:22 AM   [ Ignore ]   [ # 5 ]
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Hi Adrian,

my tangible objects are simple acrylic with a diffuser glued on top. And the fiducials are glued under.
Did you make improvements in your setup?

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