Florian Fournier, William Cassarly and Jannick P. Rolland published a paper, ‘Fast freeform reflector generation using source-target maps,’ in Optics Express 18(5), 5295-5304 (2010)
Abstract: We propose a freeform reflector design method based on the mapping of equi-flux grids between a point source and a target. This method imposes no restriction on the target distribution, the reflector collection angle or the source intensity pattern. Source-target maps are generated from a small number of target points using the Oliker algorithm. Such maps satisfy the surface integrability condition and can thus be used to quickly generate reflectors that produce continuous illuminance distributions.
March 2010