Modeling the Spatial Energy Distribution of Complex Light Sources for Lighting Engineering

Abstract

In lighting engineering the precise simulation of a lighting project requires a light source model which has the ability to reproduce real light sources. The models which assume the spatial energy is diffused over the light source, are not sufficiently precise, since real light sources do not have uniform spatial energy distributions. Other models based upon gonio-photometric diagrams provided by manufacturers have been developed, but they introduce an important error in the computation of the illumination of surfaces close to the light sources. We propose a new method which considers a light source as a domain giving off energy in the scene using an interface zone. Thus, the spatial energy distribution is computed over the interface using a projection method. This model can be used to help designers. Moreover, as the spatial energy distribution is pre-calculate, our light source model can be used as a sub-domain of the scene in a radiosity global illumination simulation.