Differential Raytracing for Single and Mutiple Scattering Simulations

In differential raytracing ray bundles with an infinitesimal angular spread are propagated through an optical system. This method implicates two major benefits compared to conventional geometrical ray tracing. First, radiometric calculations can be performed much more efficiently and accurately. The second advantage is that the differential information contained in each ray bundle can be used for ray variation. For instance the end position of a ray is varied by changing its start direction while its start position is kept fixed. In our talk we concentrate on two applications in modeling light scattering. First we show a simulation of a light scattering device, which is orders of magnitude faster than conventional raytracing. Second we work out a novel solution of the radiative transfer equation which can be used to compute the scattering from turbid liquids, where multiple scattering is dominant.