I just got my Fire-i with a non-IR filter coated lens in a few days ago. Before I was using an Xbox Live camera. My Xbox camera does an excellent job, but the Fire-i not so much. I am using a cover for a remote control terminal from my projector as filter material. I cannot explain why the Xbox cam produces more vibrant results. My only guess is that the lower quality CCD will produced a worse quality image, but better for our application. My setup is FTIR. I am curious to hear some opinions on this situation. Below is a picture from the Xbox camera. I do not not one from the Fire-i readily available.

Are you using the DVSL-driver or the CMU-driver?

Neither.....I am using a Mac. I think that this is less of a driver issue and more of a hardware issue.

My personal experience .....  My spc900nc gets really good results (somewhat IR sensitive and high framerate)
but my xbox360 live vision cam is much more sensitive(brighter blobs) and minimum of 30+ frames a sec.
**so sensitive that at this point all i have on my screen is rosco on top and getting nearly zero force ....

FTIR using 104 940nm LEDs

Unibrain Fire-i

xbox360 vision cam

The unibrain has much better lens options but even without the IR blocking it is nearly dead to 940nm IR.

Well that’s probably because the unibrain is more sensitive in the 800nm range and 940nm is high for it. LEDs should really be catered to the camera spec. If you used a 850nm LED, you may see your results flipped.

cerupcat - 25 June 2008 12:21 PM

Well that’s probably because the unibrain is more sensitive in the 800nm range and 940nm is high for it. LEDs should really be catered to the camera spec. If you used a 850nm LED, you may see your results flipped.

Quite possible!

I’d love to see if someone with the 850nm LEDs can prove that point.

I’m stuck with the 940s because I spent money on a Thorlabs IR filter for that range.

Paul - 25 June 2008 12:44 PM

cerupcat - 25 June 2008 12:21 PM

Well that’s probably because the unibrain is more sensitive in the 800nm range and 940nm is high for it. LEDs should really be catered to the camera spec. If you used a 850nm LED, you may see your results flipped.

Quite possible!

I’d love to see if someone with the 850nm LEDs can prove that point.

I’m stuck with the 940s because I spent money on a Thorlabs IR filter for that range.

Paul,

There is no need in proving anything. The Unibrain Fire-I camera uses the Sony ICX-098BQ CCD sensor.
I attached the spectral sensitivity curve for this sensor. As you can see from the chart, the light response clearly drops as the wavelength increases.
So while at 850nm the response is around 0.2 (1/5th of the total range), at 940nm this drops to about 0.75 which is more than 2 times smaller!
This is why you get low brightness blobs. Keep in mind that these camera CCDs are ‘tuned’ for a color spectrum of the visible light. Therefore deviating much from this in terms of the light wavelength will not only result in lower light response but also a higher noise.
The whole point of having the IR light in MT setups is so that it is not visible by human eye and so that there is no intereference with the image projected to the screen. Therefore using near IR is completely fine, and there is no need to go as high as 940nm (unless you are using more expensive specialized cameras sensitive in this wavelength range).

~Alex

Here’s a link fron CNET. It’s a list of webcams with CMOS sensors.
They’re faster, cheaper and from what I could find on the web, a bit more sensitive to IR than a CCD.

http://shopper.cnet.com/4566-6502_9-0.html?filter=500551_5005572_

Tinkerman - 25 June 2008 09:20 PM

Here’s a link fron CNET. It’s a list of webcams with CMOS sensors.
They’re faster, cheaper and from what I could find on the web, a bit more sensitive to IR than a CCD.

http://shopper.cnet.com/4566-6502_9-0.html?filter=500551_5005572_

Tinkerman,

That is a great find!
Maybe we should have a new thread comparing CCD and CMOS cameras for IR sensing applications.
And maybe we should create a list of top quality cameras (both CCD and CMOS) as well as the cheapest ones.

~Alex

Thanks to both Tinkerman and Alex… great information.

Looks like I might be investing in some 850nm LEDs and another Thorlabs filter.