This test is nowhere near as comprehensive as the big one we did at LEAFFEST a few years ago, but I wanted to know if we could switch Infragram Webcams to red filters as we've begun to do with other Infragram conversions. I set up one of each and ran it through a couple test scenarios, but I'd like to ask folks input on if this seems to be working.
The first is of a bed of weeds in a nearby park. Running with the preset for blue filters, colorized NDVI:
And same but with the red filtered camera, with the red filter preset:
The original image is:
- Blue: http://infragram.org/i/55661b5ffed547da29000064
- Red: http://infragram.org/i/55661b3cfed547da29000063
I did a second test of a potted houseplant on my back porch:
Infragram links here:
One thing I immediately notice is that for areas with low dynamic range data, in dark regions like shadows, the blue filter technique returns lots of artificially inflated values (red artifacts) which likely aren't really high productivity zones, but just noise. The red filter technique does not cause this effect.
It does seem like the red filter version can work with this webcam. But I'd like to hear from others to get consensus.