TTRG integration of light transport equations: Azymuthally integrated   radiances inside a Lambertian foliage
  A method for numerically integrating transport equations, combining transfer matrices, transmission-reflection matrices, and Green's matrices (TTRG), was recently proposed. The present paper deals specifically with azymuthally integrated radiances inside a horizontally homogeneous canopy of Lambertian leaves. Its main purpose is to test the accuracy of TTRG by applying it to non-trivial models possessing analytical solutions, that were given in another paper. Comparison is made with the widely used iterative integration (or 'relaxation' method). Cases of extreme light trapping are given for which iterative integration is hardly practical, while TTRG remains as accurate and rapid. 
Sophie Royer and Antoine Royer