I have met the same problem as follows:
First, Although I have tried several places,I can’t make the IR-light in a equality state.
Second, I don’t know what is frosted lee filter refer to,I can’t buy it here, I used aluminum foil replace it, but no effect, does someone give me a another better solution?
Third, the image of IR on the acrylic always appears in the corner of the cam, and the image disturb me to touch the acrylic.
Forth, No matter how I adjust the contrast, when my figure move on the screen, part of screen will sensitive,and part of it will none response.
Thanks a lot!

Feel lucky, I cant even get DI to work…

hi denghuaqin,

could you post some pics of your setup, and camera capture..
maybe i can help you, i have build several DI setups..

thanks ,Tim Roth
I have four IR illuminant in the four corner ,see with a IR-pass camera ,the middle is more bright. than corner.
I use 30 angle Led.

I thingk that take the IR even must have nice skill,can you send more picture to me so I can see how do you make IR even for your DI table?My email is

Finaly, I also have another problem. my DI multitouch table not work in the daylight. because the daylight is bright than IR illuminant.
Does your DI multitouch table can work in the daylight?
Thanks.

sorry took a while to answer… sorry
Well you could check my blog, i have detailed specs of my DI setup..
I tried aluminum foil as well, did´t really work for me though.. the lee reflector worked a lot better.
I also tried painting the inside of the box with white paint, which worked to some extend.. but not really to well.
maybe you could post a screenshot of your camera capture?

Daylight issues can be solved by using a IR Bandpass filter… (doesn´t help if your table
is next to a windows though)