Light pollution assessment using photographical methods

Abstract

Light pollution is a phenomenon that has been reported since a long time, but the specialist's reaction is still modest. There are some attempts for specific regulations. Using photographic tools can be a solution, especially because of the possibilities to achieve global measurements of the lighting field. The purpose of this paper is to substantiate a work in which the general public aware of the phenomenon, based on qualitative evaluations and quantitative assessments. Moving from photography at night, for which there are sufficient quantitative information, towards the assessing of light pollution (not even benefit from an operational definition) is another important goal. And this is not only about street lighting (for which there is a description of the specific efficiency) but also for architectural lighting and advertising. The outcome sought by the author is finding a way to better observe early forms of light pollution and also to promptly report the serious situations or the exaggerate levels of the phenomenon. The method is based on low level aerial photography, and data processing to make the difference between useful light (on the street, on the facades etc.) and light pollution. Computing the global fields of light, received at different altitudes, it is possible to identify the pollution, even the source of it. In other case, there is no feedback mechanism to perform the self-limitation of the negative effects of light pollution. This could represent a main contribution to the designing of lighting systems.