4 of 5
4
Ideas for my next DSI project / Object Recognition + LCD (LED) TV
Posted: 09 September 2010 10:38 AM   [ Ignore ]   [ # 46 ]
Avatar
RankRankRank
Joined  2010-01-15
Total Posts:  419
Sr. Member

Okay, so I was running my EndLighten backlight last night for testing (was taking a few days off after PAX and demoing tables).  It is not as diffuser-esk as I remembered. 
The LCD screen I’m using works really well without an additional diffuser and the endlighten layer looks great with the original backlight dropped to the floor, but this is not
the solution we’re looking for to enable an LCD system to both have Fid’s and prevent the user from seeing below the surface.

I’ll keep plugging at it and see if I can’t come up with a viable solution.

Regarding video’s of the Fid tracking in use, right now the fid tracking is spotty.  the camera I’m using for testing is a ps3 cam and only one of them.  So the result is a poor
image which 1.4a of CCV can track the fid on, but only intermittently. 

If the Firefly MVU-13SC (1328x1048) can handle the fid’s for my screen I’ll start looking to arrange for a bulk order to lower cost if anyone is interested.  I’ll start a post to
that effect after I’ve tested the cameras.

 Signature 

Personal MT Blog
Mesa Mundi Inc. and Online Store

Profile
 
 
Posted: 09 September 2010 04:57 PM   [ Ignore ]   [ # 47 ]
RankRank
Joined  2009-01-30
Total Posts:  201
Member

okay, so the endlighten seams to be not the solution =(

I can also run my setup without any diffuser at all and get a nice picture but as you said i can look inside the box.
With the weak diffuser i can only see some really tiny spots where the backlight seems to be not as strong as the rest (this is where the cameras are located).
But you can only see these spots if you look on a image with very bright colors (eg. an all white background).

Fiducial tracking is the same here, not very satisfying with a single cam.
Four cams work very nicely, although it would be better with no diffuser cause the markers appear a bit blurry.
For my 32” Setup 4 cams with 640x480 are enough to track the fiducials quite reliable but i think that the blurring on bigger screens would be too much for this resolution.

So I,m quite satisfied with my setup at the Moment.
Only thing I’m trying to make better is to put some more white leds in to make the image of the lcd a bit brighter.
Although it is bright enough to see everything clearly but compared to my macbook here the brightness seams quite a lot weaker.

Profile
 
 
Posted: 10 September 2010 03:11 AM   [ Ignore ]   [ # 48 ]
Avatar
RankRank
Joined  2010-05-31
Total Posts:  181
Member

So i have thought about a solution with other material for the Fiducials.
Maybe 2 components, one reflect IR, the other absorb it, to get higher contrast.
So black & wihte does that too but not as good as spcial materials.

what do you think about this? could it work?

greez

JonnyB

 Signature 

There are only 10 types of people in the world:
Those who understand binary, and those who don’t.

Profile
 
 
Posted: 10 September 2010 09:40 AM   [ Ignore ]   [ # 49 ]
Avatar
RankRankRank
Joined  2010-01-15
Total Posts:  419
Sr. Member

Yeah the reflect and absorb method is the same one that MS uses to make their byte code object appear.  I’ll be testing with a 7d512 layer for a diffuser this weekend.  I used it in my original build for an RP setup and it worked well for fid tracking.  Finally, I am also preparing to test a 2 way mylar mirror which I’ve got setup from yet a different build, which I’m going to add to the bottom of the system.  The final layering would be as follows:

======= EndLighten (IR)
------------ LCD HDTV
======= EndLighten (White LED)
------------ 2-way Mirror’d Mylar
======= (possibly a clear support layer)

I should mention that the dual sheets of XL are very heavy but very strong. 

Alternately I’m looking into various low-cost acrylics for creating tokens with printed or insertable fid’s.  I hope to have a sample pack from the vendor I’ve got in mind in the next few days.

 Signature 

Personal MT Blog
Mesa Mundi Inc. and Online Store

Profile
 
 
Posted: 14 September 2010 07:38 PM   [ Ignore ]   [ # 50 ]
RankRankRank
Joined  2009-05-05
Total Posts:  461
Sr. Member

Payne so in the end you got rid of the Edge lit Endlighten as the backlight? what did you end up with?

i see a few posts ago you listed “trueLED Plexiglass” wat is that? was this what u used for the backlight plastic instead of Endlighten?

The other thing I wanted to confirm, in your Camera Settings, what were the camera values you adjusted?
You mentioned you set Gain to minimum of 20 and you mentioned the Exposure should be turned as high as possible, is this correct?

Also may i ask what LCD 32” model you are using?

Profile
 
 
Posted: 15 September 2010 02:46 AM   [ Ignore ]   [ # 51 ]
RankRank
Joined  2009-01-30
Total Posts:  201
Member

@cityguru:

I used about 5m white led strip which i sticked to the bottom of my table, above is this trueLED Plexiglass which spreads the Light evenly like a diffuser.
It is said to be the very good for LED Backlighting and comes from RÖHM PLEXIGLAS®

I adjusted gain and exposure. Gain should be as low as possibly cause it makes the picture grainy if set to high.
Exposure should be set as high as needed to give a good contrast between blobs and background.
Currently my value for gain is set to 23 and exposure at 186 with led strips from the community order which are similar to the environmental led strips

You can see the model in the beginning of the video i posted in this thread (sadly its only 720p because of my budget)

Profile
 
 
Posted: 17 September 2010 10:44 AM   [ Ignore ]   [ # 52 ]
Avatar
RankRankRank
Joined  2010-01-15
Total Posts:  419
Sr. Member

Okay, finally got a chance to do some more testing on this. 

I applied the Mylar in a couple of different configurations and found that it creates a very undesired, but not unexpected, effect.

The two way mirror was too reflective when the back light was lit.  Additionally, because of the semi-transparent nature of the material, the lighting of the back light negated most of the upward facing reflectiveness.  So also not a solution.

This led me to grab a sheet of Acrylite 7D512 RP which I was using for a rear projection setup and attached it as follows:

===== EndLighten (IR)
--------- LCD
===== EndLighten (Support)
--------- 7D512RP

The 7D512 works great for Fid’s as it is not a frosted glass but an actual floated medium in the acrylic.  The above layout does not work however.  As soon as I’ve got time, I’ll pay around with swapping layers.  The 7D512 is rather thin, so I do not think it is a good bottom support layer for the LCD even though that may be the ideal location for the material.  In the end I’ll probably end up with one of the following configurations:

===== EndLighten (IR)
--------- LCD
--------- 7D512RP
===== Rigid acrylic or EndLighten

or

--------- 7D512RP
===== EndLighten (IR)
--------- LCD
===== Rigid acrylic or EndLighten

Also worth noting.  I’ve been testing the EndLighten back light option.  With the White LED’s I have, I am not getting enough light to be additive to the light generated from the existing back light.  I have tested the LCD with just the White LED’s for back light and it is usable, but barely.  It may be possible to create a back light using EndLighten supplying that the LED’s are significantly strong then what I have.  I am using a strip of daylight white (~266 lumens/meter).  Environmental Lighting has some brighter stuff that might work though (~592 lumens/meter).  I’ll try to take some photos of the LCD with the LED/EndLighten BL as well as the the standard BL.

Finally, the reason to keep the diffuser/RP material near the top of the stack is to minimize distortion of the object placed on the surface.  I think a lot of the diffuser + Fid’s problems are a direct result of the distance between diffuser and object.  I’m hoping that my LCD is bright enough that the 7D512RP on top will be the ideal stack.  Alternately I’m looking to order some IceAV to test with since it is a significantly thin medium.  I’d love to know if anyone has a US distributor for IceAV.

 Signature 

Personal MT Blog
Mesa Mundi Inc. and Online Store

Profile
 
 
Posted: 17 September 2010 12:37 PM   [ Ignore ]   [ # 53 ]
RankRank
Joined  2009-01-30
Total Posts:  201
Member

wouldn’t the 7D512RP blur the LCD image if placed on TOP ?
I also messed around with the ideal layering a lot.
Diffuser above the LCD never worked for me…

Profile
 
 
Posted: 17 September 2010 03:03 PM   [ Ignore ]   [ # 54 ]
Avatar
RankRankRank
Joined  2010-01-15
Total Posts:  419
Sr. Member

Well, yes, there is the chance that it will blur it too much.  Now, here’s an idea wink

7D512RP
LCD
EndLighten (IR)

We would loose the full range of FTIR and have to rely solely on the DSI aspect, but that’s kind of the point right?
The 7D512RP looks good when abutted to a fid or the LCD.  So it stands to reason that if the layering above were possible, then we’d get a solid setup.  The only real problem I foresee is that the 7D512 is thin enough that it may not protect the screen when pushed on by a gang of kids (which has been my test case for solidity of design thus far).  Still this is worth attempting.

If I get a chance I’ll mess with this weekend.  I may rebuild my frame to support rapid switching of layers without touching the IR Frame.
Hrmm.  I’ll have to think about that one.

It is also “Fall Cleaning” at my house/shop this weekend, so a rebuild might languish a couple more days.

 Signature 

Personal MT Blog
Mesa Mundi Inc. and Online Store

Profile
 
 
Posted: 17 September 2010 04:44 PM   [ Ignore ]   [ # 55 ]
RankRank
Joined  2009-01-30
Total Posts:  201
Member

how thin is the 7D512RP ?
I tried a protective top layer on over the LCD some time ago, it was about 4mm and it bended under its own weight - so pretty useless as top layer over the LCD

Profile
 
 
Posted: 05 October 2010 09:20 PM   [ Ignore ]   [ # 56 ]
Avatar
RankRank
Joined  2009-09-12
Total Posts:  121
Member

Got an idea...sorry but i still have faith in the enlightened backlight.

=================[enlightened IR]
=================[LCD]
=================[englightened WHITE]
=================[cold mirror]

This might work cause when you use enlightened with any light it diffuses it throughout the glass, the thing with the cold mirror is that it will reflect all light upward and allow IR to pass. reflecting all the light upward should allow less illumnication to escape out the back. This is similar to edgelit LED TV setups but cold mirrors make this unique

Profile
 
 
Posted: 06 October 2010 02:05 AM   [ Ignore ]   [ # 57 ]
Avatar
RankRank
Joined  2010-05-31
Total Posts:  181
Member

Sounds good!

I want to test this.
But first i have a maybe stupid question.

read this on “Wiki”

cold mirrors can be designed for an incidence angle ranging between zero and 45 degrees

So I can´t explain that well so i painted it in a few seconds.

does that mean picture one or two?

Image Attachments
01.png02.png
 Signature 

There are only 10 types of people in the world:
Those who understand binary, and those who don’t.

Profile
 
 
Posted: 06 October 2010 06:27 PM   [ Ignore ]   [ # 58 ]
Avatar
RankRankRank
Joined  2010-01-15
Total Posts:  419
Sr. Member

A rigid cold mirror might work were as my mylar failed.  Do you know where to get a cold mirror large enough?  Edmund Scientific seems to only have 4"x5" as a max size.

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productid=1900

Also, cold mirrors look pretty darn expensive.

 Signature 

Personal MT Blog
Mesa Mundi Inc. and Online Store

Profile
 
 
Posted: 06 October 2010 06:33 PM   [ Ignore ]   [ # 59 ]
Avatar
RankRankRank
Joined  2010-01-15
Total Posts:  419
Sr. Member
grimjack2600 - 06 October 2010 06:27 PM

A rigid cold mirror might work were as my mylar failed.  Do you know where to get a cold mirror large enough?  Edmund Scientific seems to only have 4"x5" as a max size.

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productid=1900

Also, cold mirrors look pretty darn expensive.

Okay, to answer my own question, I’ve found a handful of manufacturers of “thin film coatings” which act as cold mirrors.  I’ll see if I can’t get some samples.

 Signature 

Personal MT Blog
Mesa Mundi Inc. and Online Store

Profile
 
 
Posted: 06 October 2010 09:31 PM   [ Ignore ]   [ # 60 ]
Avatar
RankRank
Joined  2009-09-12
Total Posts:  121
Member

yeah i think you need 0 degree AOI, but i think if light shines evenly and perpendicular it should reflect back either way it will reflect alot upward. Only thing is what happened when you have alot of ambient light the screen might a become real reflective...just something to think about

i would try the film, any cold mirror real big would cost a lot of money and need custom fabrication

why would you need a rigid one it may distort a FID more?

picture two btw

Profile
 
 
   
4 of 5
4