Interreflections in Rooms by a Network Method

A network method for the prediction of the luminous-emittance distribution after interreflections in rooms with specified geometry, initial division of light flux to the room surfaces, and luminous reflectances of the room surfaces is presented. Potentials in the network are initial and total (i.e., after interreflections) luminous emittances while the surface reflectances and shape factors define the resistances. Uniform illumination of all surfaces and diffuse light-flux emission and reflection are postulated. Algebraic solutions to the networks describing infinite and cubical rooms are presented. The average illumination of any plane of arbitrary orientation, such as the working plane, can be computed by a floating potential node technique. Luminous-emittance distributions in a cubical room as obtained by Moon’s integral-equation solutions are compared with data obtained by the network method.