ABSTRACT
The goal of rendering algorithms is to create images that accurately represent the appearance of objects in scenes. For every pixel in an image, these algorithms must find the objects that are visible at that pixel and then display their “appearance” to the user. The models of light used in simulations try to capture the different behaviours of light that arise from its dual nature: certain phenomena, for example, diffraction and interference, can be explained by assuming that light is a wave; other behaviour, such as the photoelectric effect, can be better explained by assuming that light consists of a stream of particles. This section uses concepts from transport theory to intuitively explain the relations between different radiometric terms. Transport theory deals with the transport or flow of physical quantities such as energy, charge, and mass. In this section, we use transport theory to formulate radiometric quantities in terms of the flow of “light particles” or “photons.”.
