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Ideas for my next DSI project / Object Recognition + LCD (LED) TV
Posted: 24 April 2010 08:37 PM   [ Ignore ]
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ill be finished with my ongoing DSI project by end of may and i was looking for a new LCD TV with Local (LED) Dimming like LG 42LH9000

It costs ~ 1000€ and according to the Lumenlab LCD database most of the (smaller) LG monitors are easy to disassemble and only very few have FFC issues. i would love to get some ideas about DSI LCD (with object recognition) or any other method that can be build with PS3 cams and LCD(LED) TVs ?

Is it possible to use a LCD with LED backlight (FullLED /Local Dimming not edge-lit) for a DSI table with object recognition?

The LCD matrix has to be seperated from the LED backlight but is the LCD matrix layer transparent enough to allow the cameras to track blobs from the endlighten sheet placed above the LCD or is the endl. under the LCD ?

Is there any other method for object recognition with a LCD ?

e.g. LG 42LH9000 or Sharp 40LE705 both with FullLED Local Dimming

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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: 24 April 2010 10:49 PM   [ Ignore ]   [ # 1 ]
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I have tried this method, it does not seem to be transparent enough, from my experience with my DSI table i have found that you cannot get past the diffuser which u need right below the LCD matrix.  I have not tried it with just the matrix and no diffuser, but this would be pointless because if you dont place the diffuser below the Matrix then from the top you will see the entire inside of the box and it wont look good.

in my opinion i dont believe it will even see it through just the LCD matrix but like i mentioned you must use the diffuser or you will see the outlines of the camera, the backlight, etc all from the top without the diffuser.

I was considering some method of object recognition by Blob size, but its just not accurate enough.

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Posted: 25 April 2010 04:39 AM   [ Ignore ]   [ # 2 ]
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ok, i forgot the diffuser...but im sure thats not the main problem.

how did they realize object tracking ?

http://multitouch.fi/why-multitouch/

it must be very dependant on the LCD model i guess… isnt there some1 who already built a DSI LCD with OR ?

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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: 25 April 2010 01:33 PM   [ Ignore ]   [ # 3 ]
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hi,

i am currently testing my ftir lcd setup with other diffusers and also testing dsi an some other illumination.
I foud some Rosco eColor Foil wich i used for Diffusion.
I have light Frost,full atlantic frost and heavy frost.
with the heavy frost one u get the best diffusion for the image (image quality)
with the weakest one u get better results than without but the lightsource is visible.
the light forst has also one attribute that makes it perfect for objekt traking. it diffuses the light but it stays transparent for the camera.
i mean the image is nearly not blurry.

so altogether you can track fiducals quite easy but you alway see the lightsource if u dont put it out of your line of sight.

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Posted: 25 April 2010 01:43 PM   [ Ignore ]   [ # 4 ]
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well with http://multitouch.fi/why-multitouch/ you dont see the light source, so it is a good question as to how they are doing this.

Maybe they use Edge lit LED LCD, i never dissected one below but basically instead of a backlight panel its all around the sides

In theory if the diffuser is removed and its edge lit then maybe thats how they pull this off.

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Posted: 25 April 2010 01:54 PM   [ Ignore ]   [ # 5 ]
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@ cityguru

i also tried to make the backlight with endlighten. i put the led strip around the sides of the endlighten, this schould be the same as with edge lit lcds.
you need to have something white behind the lcd and the endlighten or a diffuser.
as long as the endlighten is transparent you can see inside the box if the lcd displays bright colors (e.g. white)

if you use the light frost foil then its evenly illuminated with a acceptable contrast on the image and the camera can see the fiducials very well.
And you can’t see the lightsource (leds) becasue they are on the sides of the endlighten and therefore out of the line of sight.

But the guys in the video have a much better contrast as i got in my test.
I think the poor contrast in my setup comes from the endlighten. It spreads the light up to the lcd and down in the box. so a lot of light is lost

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Posted: 25 April 2010 02:00 PM   [ Ignore ]   [ # 6 ]
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right, i know i just came back online because i realized even looking at my Edge Lit LED LCD panel in my Dell (it was broken so i tore it open).  I saw you still have to have a diffuser, so still i have no idea how they are doing this unless of course they are lying and this is really a projector in that box smile

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Posted: 25 April 2010 02:32 PM   [ Ignore ]   [ # 7 ]
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did some quick photos

001: from bottom to top: fiducial marker, endlighten 8mm, diffuser foil
the fiducial marker is clearly visible (not to blurry)

002: one white led behind the diffusion foil pointing at the foil, you can see the lightsource as a small spot on the left and the light from it which hits the foil on the right.

003: led placed on the side of the endlighten with the diffuser on top

004: same as 003 but with broken lcd form a laptop on top of the diffusion foil (you can’t see it well on the picture but the lcd is illuminated as if you look on an all black image on your pc monitor or lcd tv)

the diffusion foil was Rosco eColor 220 white frost.
wanted to make photos of my test setup but as long as it is a test setup it doesn’t stay the same for a long time wink

hope you understand my bad english, i’m from austria ^^

Image Attachments
001.JPG002.JPG003.JPG004.JPG
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Posted: 25 April 2010 06:10 PM   [ Ignore ]   [ # 8 ]
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So what your saying here is that its not the diffuser causing the issue but the LCD Matrix itself which is blocking the Fiducial recognition, is that correct?

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Posted: 25 April 2010 09:03 PM   [ Ignore ]   [ # 9 ]
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No i don’t think so that the lcd is the problem.
I made some test with only the lcd and fiducial markers and there is nearly zero distortion.
I think the diffuser is causing the problems in most setups because normal diffusing foil distorts the image to much so there is no recognition of fiducials possible.
Also the height of the acryllic glas and the distance to the diffuser is causing problems. the farer you put the diffuser away from your fiducials, the more blurry they get.
With a weaker diffuser it is possible but you lose contrast of the lcd image and in the worst case you can see the lightsource behind the lcd.
no diffuser would be the best for fiducials but the lcd image looks like crap.

the rosco foil which i used is the best i found so far. it doesn’t blur the fiducial markers to much and you get an acceptable contrast for the lcd image and if u use some kind of edge-light technique u don’t have the problem of seeing the light source.

i hope that explanation helped

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Posted: 26 April 2010 08:33 AM   [ Ignore ]   [ # 10 ]
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check out this post: http://nuigroup.com/forums/viewthread/3728/

might be the solution for your problem.

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23’’ DI projection embedded into my desk
Celine: 21’’ LCD DSI Multi-Touch
Cyclon: 42’’ Multi-Touch Device
http://www.thirtyOneFPS.com

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Posted: 26 April 2010 11:10 AM   [ Ignore ]   [ # 11 ]
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@kame

tried that a while ago but its difficult to get an even illumination of the lcd with this.
diffuser between an edgelit endligten and the lcd works best for me.
maybe if i paint the inside of the box white it helps to get a better contrast.

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Posted: 26 April 2010 11:14 AM   [ Ignore ]   [ # 12 ]
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@payne
can you post a video from your setup “in action” plz?

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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: 26 April 2010 01:42 PM   [ Ignore ]   [ # 13 ]
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if i can find enough time this week i will post a video.
what is the point of interest ? that i know what you want to see =)

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Posted: 27 April 2010 12:35 AM   [ Ignore ]   [ # 14 ]
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so payne86, it sounds like u got success then using the rosco is that correct?

Btw what kinda foil do you mean, can u post a link to the rosco material you are referring to?

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Posted: 27 April 2010 05:48 AM   [ Ignore ]   [ # 15 ]
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yes i got a little succes with the rosco. it’s not perfect because the contrast of the lcd image is not that good as with a better diffuser or the original backlight from the lcd.
i have a 30” lcd an i used a ps3eye for testing. with a wide angle lens the resolution is not enough to see the fiducials on top of the acryllic. but with a lens similar to the original one i could track the fiducials with reactivision.
so now i am trying to get a 4 cam setup to work to get a high resolution for the fiducials (bigger fiducials would also be possible but i want to stay with the original size).
Also the recognition of blobs and less ditortion of camera image would be better with 4 cams.

but lets get back to the foil.
as i mentioned in an earlier post it is Rosco eColor 220 white frost.
i bought it in a german shop, don’t know if that helps but her is the link: http://www.modulor.de/shop/oxid.php/sid/x/shp/oxbaseshop/cl/details/cnid/AAX/anid/AAXC

btw has someone a good idea for a low friction surface? cause dragging the finger over bare acryllic is far from perfect and you loose blob quality while dragging.
i already tried it with silicone and an OHP foil. the silicone was very clear and had nearly no distortion but it sticks to the acryllic to much.

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