A ray tracing model for leaf bidirectional scattering studiesA leaf is modeled as a deterministic two-dimensional structure consisting of a network of circular arcs designed to represent the internal morphology of major species. The path of an individual ray through the leaf is computed using geometric optics. At each intersection of the ray with an arc, the specular reflected and transmitted rays are calculated according to the Snell and Fresnel equations. Diffuse scattering is treated according to Lambert's law. Absorption is also permitted but requires a detailed knowledge of the spectral attenuation coefficients. An ensemble of initial rays are chosen for each incident direction with the initial intersection points on the leaf surface selected randomly. The final equilibrium state after all interactions then yields the leaf bidirectional reflectance and transmittance distributions. The model also yields the internal two dimensional light gradient profile of the leaf.
Document ID
19870065903
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Brakke, T. W. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Smith, J. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)