Accurate illumination system predictions using measured spatial luminance distributions

Source modeling is one of the key elements that enables software simulations to predict the output of an illumination system. A successful method to model a source is to use measured spatial luminance distributions over a range of view angles to synthesize rays that are then used in a Monte Carlo illumination simulation. The measurements are typically performed using a camera at numerous discrete view angles. Important issues arise when synthesizing rays at angles between the measured angles, especially when the source being measured incorporates optical elements such as a reflector.