Portable Emissivity/Reflectometer for Measurements on Curved Surfaces

The goal of this project is the development of a sophisticated hand held inspection device for evaluation of protective coatings on NAVY air vehicles. The signature of an aircraft is defined by its angular emitted energy (emissivity) and by BRDF(bi-directional reflectance distribution function) of the reflected energy. Both of these characteristics should be known for full coating characterization. However, the purpose of the measurements discussed here is not to model or predict opticalproperties of coatings, but to perform an inspection of degradation of a coating as compared to the undegraded coating. In this case a limited measurement may be sufficient. The proposed device will measure directional reflectance and calculate emittanceat two angles: 20 and 65 degrees. Both the diffuse reflectance and the specular component will be included in the measurement of the total reflectance. A modified integrating sphere will be the main part of the optical system. The instrument willmeasure reflectance in four different IR bands specified by the NAVY in Task 1 of this effort. The project will produce a modular device ready for future upgrades and expansions. Development of a commercial directional reflectance measurement andemissivity prediction device will provide a tool for field assessment of optical properties of paints and coatings. This universal tool will work on flat and curved surfaces. Further commercialized devices will be directly applicable in the field ofenergy conservation, radiative process optimization, and for corrections in spectral imaging related to remote sensing in military, geological and environmental work.