I've been working with UAV imagery (NIR and VIS) for monitoring sugarcane's post-harvest behavior in Guatemala. The images are uncalibrated and I'm using raw DN numbers for extracting NDVI and other VIs. The main purpose of the flights and analysis is count (or estimate, at least) the number of plants per row in the field. At this post-harvest stage, grass-type weeds and broad-leaf weeds are growing too, which makes the use of uncalibrated images a little bit tricky.
Anyone else working with this kind of stuff and having some experience dealing with crops and weeds during early stages of the plant?