I've been using the red filter purchased from Public Lab, and modified my Logitech c920 webcam to be able to capture NIR wavelength. I've attached some of the results taken raw and processed using infragram.
I've done white balance using the red card that has been sent to me too, but the result is not as good as it should be. What should I do to this pictures to improve the NDVI calculation? How am I supposed to do the white balance with the red card?
Is it true that by using the red filter there are some contamination of NIR in the red channel? is that why the NDVI calculation is not accurate?