Hi, very cool! Would you be willing to open source your patch by sharing it in this note? I love Max/MSP and also Pure Data/PD!

If it's easier, there is already a live video version of Infragram at Infragram.org -- you can connect directly to the webcam and run NRG, NDVI, etc etc in the browser. Does that help?

OH, i see - you have NDVI running, but want to do NRG. Well, NRG is typically showing red and green in the green and blue channels, and in the current blue filter version of the webcam, you don't have a visible red channel. But you can kind of fake it by using your infrared as red, then blue as green and green as blue. @cfastie has demonstrated this here: http://publiclab.org/notes/cfastie/11-12-2013/red-filter-rising but I think there was another more clear explanation he did of how simulating NRG could be achieved with a blue-filtered camera. Chris, can you help?

Great lead image, btw, it's so clear to see!

i tried and failed to make a max patch like this last year. The issue I was facing was that the calculations need to 1) allow for negative numbers, and 2) perform floating point operations. The standard matrix objects are 8-bit CHAR (integer) matrixes that only allow values from 0-255. Jitter can definitely do this calculation I just couldn't figure out how to successfully build a floating point matrix, do the math, and then convert it back. I was playing around with using the jit.expr option and am pretty sure that it has to be used for all the math operations rather than the integer-only standard objects.

warren, I will most absolutely share whatever I come up with. I was actually having trouble using the browser version with my mac. Also, in Max, you can do some live analysis on the image as it comes in, where as the browser can only provide a static image to analyze.

mathew, I had not considered that. That may be part of why it never seemed to process properly. I'm still just trying to figure out how to layer the channels to satisfy the formula. Did you work with (Near IR - Red) / (Near IR + Red) in your go at it?

lucenk - hmm, maybe you're not using the live video version of the browser version? You should definitely be able to remix channels on live video; what browser are you using, and what issues are you seeing?

I was using the (Near IR - Red) / (Near IR + Red) in my try. I was also using Max 4.5, because I bought a license ~11 years ago and haven't grabbed a new one since Max 5 came out, so it might be different.