Can I use OpenCV to detect weeds in a paddock?

edit

I am reasonably new to OpenCV and am looking to start a new project, and just wanted get some expert guidance and to know if I am barking up the right tree.

I want to build a system that can detect the colour of the actively growing green weeds on either a red road, or in a paddock with white/silver stubble background. So I just need to check for green on a video input, and trigger a solenoid to spray the weed with herbicide when green is detected. Currently on the farm I work on (about 20,000 acres) we just blanket spray the whole paddock for weeds, so just spraying the actual weeds could yield significant chemical savings (cost and environmental)

Can anyone tell me if this possible with current OpenCV algorithms? Is it possible at a fast enough rate to make it worthwhile (20km/h ish at 50-100cm above the ground)? Is it possible on cheapish hardware ie, a raspberryPi/Odroid XU4/Nvidia TX2 and camera?

I was thinking of having a stand alone computer, camera and solenoid for each spray nozzles or maybe 3 nozzles/solenoids per module, and detect which third of the image the weed is in and trigger the corresponding solenoid+spray nozzle.

Currently there is a system for sale (http://www.weed-it.com/) which I believes uses infrared/NDVI to detect the chlorophyll in the weeds. This system would cost us about $320,000 for a 36 meter wide setup, so it aint cheap. I was thinking each spray module could be built for a few hundred dollars at most. With a module retrofitted to a 36 meter spray boom, that would still end up a bit cheaper.

I plan on making this completely open source, and modular. I just wanted to check with the experts to see if this is a feasible project before I dive in too deep. I planned on doing simple colour detection to begin with, and build on the system or add features from there.

I hope that makes sense, and I hope I'm asking in the right place. I really just want to know if its possible for now, and if it would be worthwhile pursuing. Any input/questions, yes/no, criticism/encouragement is welcome.

Thanks Adam