RoboRealm Forum

No Title

Tue, 30 Nov 1999 00:11:00 EST

Nope, IR is read like the RGB image, i.e. IR signal just makes the pixel higher intensity when the IR filter is removed so it is not subtractable from the image. Because in an RGB image there are literally 3 sensors per pixel you can subtract Red from Green, etc. but unless you have a RGBI camera (where I is for IR), i.e. 4 sensors per pixel, you can't do what you are asking. You need an extra camera to act as that 4th sensor.

STeven.

No Title

Tue, 30 Nov 1999 00:11:00 EST

Steven
Thanks! Is there any way we can filter RGB only then subtract it from raw image which has both IR + RGB, which mean we got only IR only. Then use math of NDVI. Do you think it should work?
Thanks
Aman

No Title

Tue, 30 Nov 1999 00:11:00 EST

Aman,

Yes, that should be possible assuming you have the right filters. The RGB red is not a problem, the issue is that with the IR filter removed from your webcam you will need a visible light filter (you can get them from Edmund Optics) to remove all but the IR signal. Apparently, here is someone else who has done this:

http://publiclaboratory.org/tool/stereo-camera

STeven.

Converting webcam into NDVI camera using VBScript

Tue, 30 Nov 1999 00:11:00 EST

Hello There
I am wondering if there is any way to convert a webcam into NDVI camera. I removed the filter from webcam. So now camera is able to sense all spectrum of light beyond visible. Is there any way I can block RGB from image to get NIR image and generate another clone of same webcam and apply red filter. This way we can have both NIR and red image Now apply NDVI math (NIR-Red)/NIR+Red) to get NDVI number using vbscript. I tried but didn't succeed. Let me know anybody tried it earlier. All kind of help will be appreciated.