I use UAS to survey vegetation at subcentimeter resolution for my research and have found that bidirectional reflectance (BR) is a huge issue that impacts the reliability of estimates across subsequent flights. (https://www.sciencedirect.com/science/article/abs/pii/S1161030115300733)
There are solutions for this in the world of remote sensing, specifically the bidirectional reflectance distribution function (BRDF). (https://www.mdpi.com/2072-4292/10/9/1348/pdf)
Is there any existing package that facilitates the use of BRDF on raster files in R?