New approaches in multi-angular proximal sensing of vegetation: Accounting for spatial heterogeneity and diffuse radiation in directional reflectance distribution models
AMSPEC-MED automated multi-angular hyperspectral system set in tree-grass ecosystem Ecosystem 3-D and FOV ray casting models simulate heterogeneous sensor's observations. Diffuse radiation included in Reflectance Distribution Functions (RDF) improves model. The model achieves the unmixing of tree and grass hemispherical-directional RDFs. Comparison to MODIS BRDF product and hand held spectral data cast r2 ∈ [0.74, 0.88].