The FLIGHT model is based on Monte Carlo simulation of photon transport (North (1996); Disney et al. (2000); Barton and North (2002)), and has been developed to simulate the observed reflectance and LiDAR response of three-dimensional vegetation canopies. Evaluation of bidirectional reflectance is achieved by simulation of the photon free-path within a canopy representation, and simulation of the chain of scattering events incurred by a photon in its path from the source to the receiver or to its ab- sorption. Multiple scattering between different foliage elements and with the ground is thus modelled. LiDAR waveform response is simulated by including a time variable in the calculation. Foliage is ap- proximated by structural parameters of area density, angular distribution, and size, and optical proper- ties of reflectance and transmittance. Leaves are approximated as bi-Lambertian scatters, and the an- gular distribution of incident diffuse light may be modelled explicitly.
Below is a representation of a coniferous forest as used by FLIGHT
- North, P. R. J., Three-dimensional forest light interaction model using a Monte Carlo method, IEEE Transactions on Geoscience and Remote Sensing, 34, 946.956, 1996.