On canopy spectral invariants and hyperspectral ray tracing

In this paper we present a method for the efficient simulation of canopy hyperspectral reflectance using Monte Carlo Ray Tracing. The method essentially describes the scattered radiation in terms of spectral invariants that gives an expression as a series of powers of leaf single scattering albedo. This can then be post-processed to describe the scattering regime for arbitrary leaf spectral functions. The spectral invariant expression is explored to interpret some of its features. Some practical uses of this include the use of truncated ray tracing methods that can be adjusted for unsampled scattering orders by consideration of energy conservation.