Effects of Multiple Photon Scattering in Deciduous Tree Canopies

摘要

Detecting objects hidden beneath forest canopies has proven to be a difficult task for optical remote sensing systems. Rather than relying upon the existence of gaps between the leaves, our goal was to use the light that is scattered from the leaves to image through dense foliage. We developed a Monte Carlo canopy propagation model to simulate the scattering of light through a maple tree canopy. We measured several forest parameters, including the gap fraction and maximum leaf area density of a real test canopy and applied them to the model. We ran the simulation for 80 deg illumination and reported on the results in the ground and receiver planes. We then authenticated the validity of the model by illuminating a test forest at an 80 deg angle, collecting data both on the canopy floor and in a monostatic receiver, and comparing the results to the simulation. Additionally, we examined the accuracy of the model in accounting for seasonal canopy variations and verify the simulation with experimental results. Lastly, we investigated methods for boosting the signal- to-noise ratio (SNR) of detected photons and make SNR calculations for various illumination angles.