Infrared camera will be use in this installation. It will only detect infrared light(in this case blob from the surface). I have to modified the camera in order to make the camera detect only the infrared light and ignore the rest. There are few method to modified the camera.
Some camera has infrared-block filter. I need to remove the filter first. Once the camera is modified to being able to see normal light as well as IR-light, I need to apply
an IR-pass filter. This IR-pass filter, lets all the IR through, but blocks out most of the visible light.
There are different materials that can use for this purpose:
- IR-pass filter
Image via here.
An IR-pass filter is a special filter that only passes through IR on a certain frequency (760 nm to for example 1000 nm). So it basically blocks out all other light, that’s not within that region, that would be most of the visible light.
- IR-band pass filter
Image via here.
The IR-band pass filter only passes through IR on a specific frequency.
For example: 880 (nm). So if I use 880 (nm) IR-LEDs and I use an IR-band pass filter of 880 (nm) as well, I will get the best optical performance, because all the light is blocked out, except for the specific IR from the LEDs.
- Black photo negatives
Image via here.
Another option is to use negative film. Just use several layers of entirely black photo negatives on the lens.
Conclusion
I probably going to use negative film as IR filter because of a low budget scenario and usability. I serious need a sponsorship.
vi) Infrared light.
Infrared is a portion of the light spectrum that lies just beyond what
can be seen by the human eye. It is a range of wavelengths longer than visible light, but shorter than microwaves. In this project infrared light will be use to detect finger touch on the surface.
Image via here. IR LED kit.
Reference.
http://nuigroup.com/forums/viewthread/3117/
http://nuigroup.com/forums/viewthread/4459/
http://wiki.nuigroup.com/How_to_Modify_Cam
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