1. INTRODUC 
In the past. 
assessment * 
88% for est: 
cultivated | 
resolutions 
various res 
which consi: 
Digital Mul: 
Color-Film | 
experiences 
sufficient 
sensing stu 
materials ai 
operation, ° 
path, and r 
thus import: 
characteriz 
the BRDF ex 
followed to 
under diffe 
Three Band | 
for taking 
growing sta 
reflectance