Characterization of Three Drone-mountable Multispectral Cameras Using a Canopy Radiative Transfer Model to Observe Paddy Fields

Abstract

We used a canopy radiative transfer model, PROSAIL, with simulated paddy canopy reflectance and vegetation indices (VIs) to investigate the characteristics of three drone-mountable multispectral cameras. The leaf area index (LAI), diffuse light ratio, and solar zenith angle were varied to create differences in reflectance and VIs due to changes in the growth stage and light environment. Different wavelength regions of each camera caused significant differences in both reflectance and VIs in the red edge band. Changes in the diffuse light ratio and solar zenith angle changed the values even at the same LAI; therefore, to obtain reliable results, appropriate observation conditions must be set for aerial photography by drones with multispectral cameras. The VIs that use the red edge band were the least affected by the observation conditions, and were less likely to be saturated at high LAI. However, drone-mountable cameras can be effectively used to observe paddy fields because the differences in the values of reflectance and VIs among cameras can be corrected.