Thermal imaging is widespread, but it is extremely difficult to do quantitatively due to poor knowledge of the target surface emissivity, reflections and thermal imager non-uniformity. The aim of this work package is to develop techniques for traceable quantitative thermal imaging, for the low-to-medium temperature range of 100 °C to 500 °C with uncertainty less than 5 °C, by using objects with known temperature (e.g. phosphors) in the field of view of the thermal imager, including the emissivity characterisation (e.g. of the surface or of the phosphor itself) and in-situ correction for imager non-uniformity.

• The first task identifies suitable phosphors and methodologies for using them in the field of view of thermal imagers.
• The second task is concerned with measuring the emissivity of the target surface and of the phosphor itself using the various methodologies developed.
• The third task develops methods for thermal imager non-uniformity and thermal imager calibration in conjunction with WP4.
• The fourth task brings these methods together for direct comparison and validation.