Aerial thermography for energy efficiency of buildings: the ChoT project

The ChoT project aims at analysing the potential of aerial thermal imagery to produce large scale datasets for energetic eciency analyses and policies in urban environments. It is funded by the Italian Ministry of Education, University and Research (MIUR) in the framework of the SIR 2014 (Scienti c Independence of young Researchers) programme. The city of Bologna (Italy) was chosen as the case study. The acquisition of thermal infrared images at di erent times by multiple aerial ights is one of the main tasks of the project. The present paper provides an overview of the ChoT project, but it delves into some speci c aspects of the data processing chain: the computing of the radiometric quantities of the atmosphere, the estimation of surface emissivity (through an object-oriented classi cation applied on a very high resolution multispectral image, to distinguish among the major roo ng materials) and sky-view factor (by means of a digital surface model). To collect ground truth data, the surface temperature of roofs and road pavings was measured at several locations at the same time as the aircraft acquired the thermal images. Furthermore, the emissivity of some roo ng materials was estimated by means of a thermal camera and a contact probe. All the surveys were georeferenced by GPS. The results of the rst surveying campaign demonstrate the high sensitivity of the model to the variability of the surface emissivity and the atmospheric parameters.