I've recently bought a better webcam in order to improve optical tracking.
It's a Philips SPC900NC. I found it at a good price in a on-line store in Italy. For sure it will be better than the first webcam I used (a Logitech QuickCam, wich at least was quite easy to mod for IR :).
The SPC9000NC has a good sensitivity in low light conditions (CCD sensor) and it can run at a decent frame rate (~30 fps) if used at 320x240 on an usb 1.1 connection. Of course the camera can work at full frame rate (60 or 90 fps, interpolated) and resolution (640x480) on an usb 2.0 connection.
The SPC900NC with a nice flexi-tripod :)
I choosed the clean way, the only problem was to find a reseller of the needed kind of optics. In the end I found it here.
The 4.3mm S-mount objective without the IR coating
You can find some nice hints on SPC900NC IR modding here.
Another important aspect is optical insulation from the ambient lighting in order to allow for a flawless IR detection from the camera. Of course you can also avoid using optical insulation, but only if you're working in absence of ambient IR light (low light conditions or with i.e. neon lights).
For this purpose i will be using an obscuring cloth that will be cut in order to follow the perimeter of the table structure.
The Light-blocking sheet
Later on I'll dig into the realization details of the interaction surface.
It's a Philips SPC900NC. I found it at a good price in a on-line store in Italy. For sure it will be better than the first webcam I used (a Logitech QuickCam, wich at least was quite easy to mod for IR :).
The SPC9000NC has a good sensitivity in low light conditions (CCD sensor) and it can run at a decent frame rate (~30 fps) if used at 320x240 on an usb 1.1 connection. Of course the camera can work at full frame rate (60 or 90 fps, interpolated) and resolution (640x480) on an usb 2.0 connection.
The SPC900NC with a nice flexi-tripod :)
One of the issues with SPC900NC is that the IR-block filter is incorporated over the optics in the form of a thin coating. Since we need exactly the opposite (having an IR-pass) the possible roads are two:
- If you know what you're doing you can try with mechanical methods
- Just buy new optics without the IR filter (clean/safe way)
I choosed the clean way, the only problem was to find a reseller of the needed kind of optics. In the end I found it here.
The 4.3mm S-mount objective without the IR coating
You can find some nice hints on SPC900NC IR modding here.
Another important aspect is optical insulation from the ambient lighting in order to allow for a flawless IR detection from the camera. Of course you can also avoid using optical insulation, but only if you're working in absence of ambient IR light (low light conditions or with i.e. neon lights).
For this purpose i will be using an obscuring cloth that will be cut in order to follow the perimeter of the table structure.
The Light-blocking sheet
Later on I'll dig into the realization details of the interaction surface.
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