The majority of you now know that thanks to AlexP’s work we can use lasers for blob tracking.
After TouchWall came into existance to the public , MS presented LaserTouch. -> http://www.youtube.com/watch?v=ne_QgTKjnMg
They are using a normal modified webcam over a tilted LCD panel and capture blobs formed from two lasers.
I think some of us should try it, just imagine what benefits this would give: ease of construction , portability prototyping.
A dispaly like this could be made with no modifications to the actual LCD or touchlib and asociated software.
You’d just place the camera , capture the background and off you go.
There are a few members on NUI who have bought lasers and line lenses. Alex , Fairlane , Justin.
So please , if one of you could test this baby out make a few videos , show how it performs , I think it could really help our community and jumpstart the building of more multitouch related technologies.
What really impress me is how easy the camera could see the laser reflections at fingers. Obviously, this method has some disadvantages… if you block the laser reflection to be see it by the camera, there wouldn’t be any detection and this should be very often, when you pass one hand over the other or in a lot of moments at a normal screen manipulation.
Well the obvious screen blockage would be an issue , but I’ve been making some calculations and schematics the last few days , been also experimenting with my wiimote whiteboard.
I think that a dual camera based setup from two sides could make any hd-tv into a multitouch display with no shadowing or nothing.
And a decent c2d or c2q procesor should be enough for dual camera action.I’ll post my findings tomorrow.
Nice info Vlado, I’m gonna start hunting for a webcam and those 2 lasers have to try this. I actually have 2 dvd-rom units at home. Will they do?
The laser diodes from dvd-rom might do. Make sure they are the same brand. What kind of IR filter are you using? You will need to know the laser light wavelength. Be careful since the laser diodes from cd/dvd-rom burners are way more powerful than 5-10mW.
Cd-rom based lasers are about 3.1-5 mW , that should actualy be safer than what your are using alex .And why would he need to know the wavelenght?
All cd-rom lasers are in the IR spectrum , 740nm if I recall corectly.
Cd-rom based lasers are about 3.1-5 mW , that should actualy be safer than what your are using alex .And why would he need to know the wavelenght?
All cd-rom lasers are in the IR spectrum , 740nm if I recall corectly.
Hey Vlado,
I was referring to CD\DVD burners since I saw that more and more people are experimenting with these. Remember the faster the burn speed, the more powerful the laser diode is.
The reason why I asked about the laser wavelength is because of the IR bandpass filter. If you are just using a simple film negative this is not an issue.
I actually recently experimented with lasers that are in the ~780nm range. I had some pre-fabbed for me and besides the fact that they are much cheaper, I can tell you that camera is more sensitive in this range. You can also see that by looking at the ccd sensor sensitivity graph. As a result of this I’m getting even brighter blobs than before!!!
Cd-rom based lasers are about 3.1-5 mW , that should actualy be safer than what your are using alex .And why would he need to know the wavelenght?
All cd-rom lasers are in the IR spectrum , 740nm if I recall corectly.
Hey Vlado,
I was referring to CD\DVD burners since I saw that more and more people are experimenting with these. Remember the faster the burn speed, the more powerful the laser diode is.
The reason why I asked about the laser wavelength is because of the IR bandpass filter. If you are just using a simple film negative this is not an issue.
I actually recently experimented with lasers that are in the ~780nm range. I had some pre-fabbed for me and besides the fact that they are much cheaper, I can tell you that camera is more sensitive in this range. You can also see that by looking at the ccd sensor sensitivity graph. As a result of this I’m getting even brighter blobs than before!!!
~Alex
Alex, I’m about to buy a pair of IR laser modules and reading your post make me think that the best wavelenght we should try is 780nm, isn’t?
Do you think that’s the same range for most commercial cameras (webcams)?
Probo , whatever wavelenght you buy , as long as it’s IR it’ll be fine , with the filter removed webcams are sensitive to every kind of infrared.
There’s a few people on this forums experimenting with 840nm lasers , and getting great results.
As long as your laser is IR and between 5-10 mW it should be fine.
Cd-rom based lasers are about 3.1-5 mW , that should actualy be safer than what your are using alex .And why would he need to know the wavelenght?
All cd-rom lasers are in the IR spectrum , 740nm if I recall corectly.
Hey Vlado,
I was referring to CD\DVD burners since I saw that more and more people are experimenting with these. Remember the faster the burn speed, the more powerful the laser diode is.
The reason why I asked about the laser wavelength is because of the IR bandpass filter. If you are just using a simple film negative this is not an issue.
I actually recently experimented with lasers that are in the ~780nm range. I had some pre-fabbed for me and besides the fact that they are much cheaper, I can tell you that camera is more sensitive in this range. You can also see that by looking at the ccd sensor sensitivity graph. As a result of this I’m getting even brighter blobs than before!!!
~Alex
Alex, I’m about to buy a pair of IR laser modules and reading your post make me think that the best wavelenght we should try is 780nm, isn’t?
Do you think that’s the same range for most commercial cameras (webcams)?
Cheers!
Either 850nm or 780nm will work. If you are talking about the inexpensive camera it will probably work the same.
Now once you start moving towards the high capture frame rates with shutter times <10ms you’ll see that things like good ir bandpass filter, laser placement and wavelength will play very important role in the performance of your setup.
Probo , whatever wavelenght you buy , as long as it’s IR it’ll be fine , with the filter removed webcams are sensitive to every kind of infrared.
There’s a few people on this forums experimenting with 840nm lasers , and getting great results.
As long as your laser is IR and between 5-10 mW it should be fine.
AlexP - 08 July 2008 05:55 PM
Either 850nm or 780nm will work. If you are talking about the inexpensive camera it will probably work the same.
Now once you start moving towards the high capture frame rates with shutter times <10ms you'll see that things like good ir bandpass filter, laser placement and wavelength will play very important role in the performance of your setup.
~Alex
Thanks Vlado and AlexP!
That’s exactly what I need to hear. I will buy my modules at 808nm, so when I try to make it work whit cheap webcams or more sophisticated cameras, could be as close as I can to the best posible range.
.And why would he need to know the wavelenght?
