Fig. 3From: The impact of variable illumination on vegetation indices and evaluation of illumination correction methods on chlorophyll content estimation using UAV imageryEmpirical line method illumination correction curve based on reference panels. The left-hand figure is for a sunny day (14th, August) and the right-hand figure is for an overcast day (18th, August). The X-axis represents the image raw DNs of panels captured under each scenario, and the y-axis is the reflectance of reference panelsBack to article page