Relationship between photon flow and the perception of light field under simple lighting environments

Abstract

In our previous study we proposed a new method, “photon flow”, to visualise the light propagation in space. Theoretically the photon flow depicts the physically correct light distribution, however, it was yet unclear whether people could correctly read the physical light field in actual spaces by observing the photon flow. Therefore, in this study we verified the relationship between the light field perceived in the real space (visual light field) and the one estimated by observing the photon flow. The experiment was conducted using the method of a white sphere, on which shade represents the light field at that point. We clarified the characteristics of the perceived light field in a simple rectangular space with one spotlight or two. The perceived light field when observing the photon flow was basically similar to the physical light field when there is one spotlight in the space. However, under the more complex scene, the subjects sometimes could not predict the physical light field well when seeing the photon flow. Basically, the perceived light field when observing the photon flow was close to the visual light field than expected. In future work we would like to clarify under which conditions people can estimate the correct physical light field by observing the photon flow and compare the difference between experienced and naïve observers.